11th Vienna Conference on Instrumentation - VCI 2007

15 Feb 2007, 15:40 → 24 Feb 2007, 15:00 Europe/Zurich

HS1 (Univ. of Technology)

Gerald Badurek (TU Vienna), Josef Hrubec (HEPHY), Manfred Jeitler (HEPHY), Manfred Krammer (HEPHY), Meinhard Regler (HEPHY), Winfried Mitaroff (HEPHY)

VCI 2007

Conference Bulletin VCI 2007 Bulletin

Conference Poster VCI 2007 Poster

Monday 19 February

09:00 → 10:40 Opening Session

09:00 Coffee & Registration

10:00 Welcome Address

Speaker: Prof. Peter Skalicky (Rektor magnificus TU Vienna)

10:15 Word of Greeting

Speaker: Dr Hanslik (Federal Minstry of Science and Research)

10:30 Opening

Speaker: Prof. P. Schuster (President of the Austrian Academy of Sciences)

10:40 → 12:20 Session 1

10:40 Spin-off from particle detectors in the field of medicine and biology

Since the discovery of X-Rays by Roentgen in 1895 physicists have played a major role in the development of medical imaging instrumentation. More recently the technological developments in several areas of applied physics, the new generation of particle physics detectors and the development of an information based society all combine to enhance the performance of presently available imaging devices. This talk will explain the critical parameters of modern medical imaging in the context of the spectacular development of in-vivo molecular imaging, which will soon allow to bridge post-genomics research activities with new diagnostics and therapeutic strategies for major diseases. In particular the molecular profiling of tumours and gene expression open the way to tailored therapies and therapeutic monitoring of major diseases like cancer and degenerative and genetic disorders. Moreover, the repeatability of non-invasive approaches allows an evaluation of drug targeting and pharmacokinetics studies on small animals, as well as a precise screening and follow-up treatment of patients. The technical requirements on imaging devices are very challenging but are rather similar in many respects to the ones of modern particle detectors on highluminosity accelerators. Examples will be given of active technology transfer areas from High Energy Physics detectors, which can significantly improve the performance of future medical imaging devices. Special emphasis will be put on the need for a globalisation of technology research and development as modern instrumentation in a vast range of applications has similar requirements and spin-off should be more and more understood as cross-fertilization between different disciplines.

Speaker: Paul Lecoq (CERN)

Paper Spinoff-Physics-Medicine.pdf (Protected)

Slides Vienna-Feb07.pdf Vienna-Feb07.ppt

11:35 Multigap Resistive Plate Chambers for EAS study in the EEE Project

The EEE (Extreme Energy Events) Project is an experiment to study very highenergy air showers through the detection of the muon component using a network of tracking detectors, installed inside Italian High Schools. The EEE project is supported by INFN, CERN, Ministero dell’Universit `a e della Ricerca (MIUR), Centro Fermi and conceived by its leader Antonino Zichichi. The single tracking telescope is composed by 3 Multi-gap Resistive Plate Chambers (MRPCs), a large (2 m 2) and cheap version of the detector designed for TOF measurements in the ALICE experiment at LHC. The multiple small gas gaps, combined with the use of a high gain (α large, λ small) and a fast gas mixture (Freon and SF6 based), provide a time resolution < 100 ps. The particle tracking is performed equipping the MRPC with 24 copper strips read at both ends by front-end electronic cards based on the fast NINO Asic and using commercial multi-hit TDCs. The detectors are built at CERN by High Schools students and teachers, shipped to Italy, tested at INFN laboratories and finally installed in the schools. In the first phase of the project the telescopes will be installed in 21 High Schools in 7 cities all over Italy. The network will soon be heavily upgraded. The first telescope, recently installed in the Liceo B. Touschek in Grottaferrata (Rome), is successfully running, opening the way for the first search of far away coincidences over a total area of ∼ 10 6km2.

Speaker: Marco Garbini (INFN Bologna)

Paper garbini.pdf (Protected)

Slides 2_Garbini.ppt

12:00 Cryogenic detectors for the EDELWEISS Dark Matter Search

EDELWEISS is a direct dark matter search looking for Weakly Interacting Massive Particles (WIMPs). In order to measure the low energies of nuclear recoils coming from the scattering of WIMPs from the galactic halo, EDELWEISS uses very sensitive Ge cryogenic detectors in a low radioactivity environment. During its first stage, up to 3 Ge 320 g detectors have been used simultaneously. The second stage, started in January 2006 with an increased detection mass and improved detectors, aims to gain two orders of magnitude in sensitivity.

Speaker: Melisa Luca (Uni Claude Bernard Lyon)

Paper luca.pdf (Protected)

Slides Vienna2007_MLuca.pdf

12:20 → 14:00 Lunch Break

14:00 → 18:30 Session 2

14:00 Satellite-borne and cosmic-ray detectors

The origin of cosmic rays has been a great mystery since they were discovered by Victor Hess in 1912. The AGASA observation of ultra-high- energy cosmic rays (UHECR) possibly beyond the GZK cutoff stimulated the field a great deal. In addition, the Kamiokande detection of neutrinos from SN1987A and the H.E.S.S. detection of TeV gamma-rays from supernova remnants demonstrated the viability of neutrino and TeV gamma-ray astronomy for cosmic-ray research. The new generation of currently- operating or soon-to-be-operating detectors for charged particles, gamma- rays and neutrinos from cosmos will get us even closer to understanding the nature and origin of cosmic rays. Detectors for UHECRs, gamma rays and neutrinos are of particular importance in order to study the origins of cosmic rays since these particles are free from the deflection due to magnetic fields. Detectors for antiparticles and gamma rays would be useful to detect cosmic rays originating from the decay of the dark matter in the Universe. I will review these cosmic-ray detectors with particular attention on the differences of ground-based, balloon-borne and satellite-borne detectors.

Speaker: Hiroyasu TAJIMA (SLAC)

Paper tajima.pdf (Protected)

Slides 1_Tajima.pdf 1_Tajima.ppt

tar ball of paper source EPS/PNG figures tajima-submission.tgz (Protected)

14:50 The Antares readout front end electronics and DAQ

The ANTARES telescope is a device of a 0.1 km size to detect high energy neutrinos. It is located in the Mediterranean Sea at a depth of 2500 meters. It consists of a three-dimensional matrix of optical modules (OM) containing photomultiplier tubes. As of September 2006 two complete lines and an instrumentation line, called MILOM, are deployed and fully operational for data taking. Three additional lines will be connected by the end of February 2007 allowing the first up-going muon track reconstruction. At the end of 2007, the full Antares telescope will be operational with twelve lines. All technical aspects are under control from the mechanical architecture to the constant improvement of the all-data-to-shore concept. This talk will focus on the photon signal processing that allows the neutrino track reconstruction. After a first review of the line architecture, we will present the signal processing and transport from the OM detector to the on-shore storage. During the R&D phases, the ANTARES collaboration has developed new concepts in terms of detector integration, front-end electronics architecture, cables, DAQ hardware architecture and software management. Finally, preliminary results of the performances of the detector will be shown.

Speaker: Frédéric Druillole (Saclay)

Paper druillole.pdf (Protected)

Slides VCI07_session2FD.ppt.ppt

15:15 The neutrino oscillation OPERA experiment Target Tracker

The main task of the Target Tracker of the long baseline neutrino oscillation OPERA experiment, is to locate in which of the target elementary constituents, the lead/emulsion bricks, the neutrino interactions have occurred and also give calorimetric information about each event. The technology used consists in walls of two planes of long plastic scintillator strips, one per transverse direction. Wavelength shifting fibres collect the light signal emitted by the scintillator strips and guide it to both ends where it is read by multi–anode photomultiplier tubes. The Target Tracker is composed of 62 scintillating walls of a total surface of about 6000 m 2. Each wall is made by assembling 4 horizontal and 4 vertical modules of 64, 7 m long, scintillating strips. This detector has observed the first neutrino interactions during August 2006. In this paper we will describe all elements used for the construction and operation of this detector and we will also give its main characteristics.

Speaker: Marcos Dracos (CNRS/IN2P3 Université Louis Pasteur)

Paper dracos.pdf (Protected)

Slides Dracos_VCI2007.pdf Dracos_VCI2007.ppt

15:40 Coffee break

16:10 A scintillator tile hadron calorimeter prototype with novel SiPM readout for the ILC

The CALICE collaboration is presently constructing a test hadron calorimeter (HCAL) with 8000 scintillator tiles read out by novel Geiger mode semicon- ductor photo detectors - Silicon Photomultipliers (SiPMs). This prototype is the first device which uses SiPMs on a large scale. We present the design of the HCAL including scintillator tile - WLS fiber - SiPM systems, mechan- ics, electronics and calibration systems. We report on measured properties of more than 10 thousand SiPMs and more than 6.5 thousand tile-SiPM systems. We present a detailed discussion of the SiPM efficiency, gain, cross-talk, and noise rate dependence on bias voltage and temperature including the spread in these parameters. We analyze the reasons for SiPM rejection and present the results of the long term stability studies of more than 5000 SiPMs. The first measurements of the SiPM radiation hardness are presented. We com- pare properties of SiPM with the properties of similar devices MRS APD and MPPC and discuss their advantages for the more than a million channel ILC calorimeter. Preliminary results of the Calorimeter beam tests at CERN are presented which represent the first operational experience with a large system based on such novel photo-detectors. A scintillator strip with SiPM readout TCMT prototype is also being con- structed within the CALICE collaboration to complement the combined ECAL and HCAL test beam program. The properties of this device are pre- sented. A possibility to make the tiles thinner or to read them without WLS fiber has been studied, and the time resolution of scintillator counters with WLS fiber and SiPM readout has been measured.

Speaker: Mikhail Danilov (ITEP)

Paper danilov.pdf (Protected)

Slides 4_danilov.pdf 4_danilov.ppt

16:35 Single photon timing resolution and detection efficiency of the DASIPM silicon photo-multipliers

Silicon photo-multipliers (SiPM) consist in matrices of tiny, passive quenched avalanche photo-diodes connected in parallel and operated in Geiger mode. Their capability to detect low optical photon fluxes with unprecedented amplitude resolution and their extreme single photon timing resolution make SiPM’s suitable for many applications. The DASIPM 1 collaboration between the Italian institutes of INFN and ITC-irst is developing, since two years, novel types of SiPM prototypes, which have a classical shallow junction non-p structure but are unique in their enhanced photon detection efficiency (PDE) for short-wavelengths and in their low cross-talk. In this report, after discussing the relevant physics of SiPM and the measurement of PDE, we publish for the first time the measurement of single photon timing resolution of the DASIPM devices. The timing resolution is studied by illuminating a single SiPM with ultra-short (∼ 70fs) and low intensity laser pulses with fixed repetition rate and measuring the time difference between next pulses. Low noise and ultra-fast electronics is used to amplify the SiPM signal and sample its waveform at high rate. Optimum timing digital filtering is adopted in order to minimize the effects of noise. Intrinsic resolution better than 40ps is measured for typical operating conditions, with λ ∼ 400nm light. The dependencies of single photon timing resolution as a function of λ and of the bias voltage are also discussed. The measurements are in agreement with our numerical simulations of the device.

Speaker: Gianmaria Collazuol (Scuola Normale Superiore, Pisa)

Paper collazuol.pdf (Protected)

Slides collazuol.vci07.pdf

17:00 Development and Study of the Multi Pixel Photon Counter

The Multi Pixel Photon Counter is a novel semiconducting photon counting device made by Hamamatsu Photonics K.K. based on concept of Silicon Pho- tomultiplier. The MPPC consists of 100-1600 APD (avalanche photo-diode) pixels, and each pixel works in limited Geiger mode with inverse bias voltage around 80 volts, which is a few volts above breakdown voltage. The MPPC has excellent features such as high gain (105 -106 ), Excellent photon detection efficiency (25-60%), low cost and torelance for magnetic field. On the other hand, the MPPC has some points which are still necessary to be improved to use at actual high energy physics experiments. In this talk I will show recent development of the MPPC and its performance. Some basic properties, such as gain, dark noise rate, inter-pixel cross-talk, photon detection efficiency will be presented. as well as results of microscopic laser scan. We will also discuss about practical application of the MPPC in various fields.

Speaker: Satoru Uozumi (Shinshu University)

Paper uozumi.pdf (Protected)

Slides VCI2007_MPPC_up.pdf VCI2007_MPPC_up.ppt

17:25 The X-HPD: Development of a large spherical hybrid photodetector

The X-HPD concept is a modern implementation of the Dumand and Lake Baikal approach to large area photon detectors, primarily aimed for water based Cherenkov detectors. The main components are an almost spherical vacuum tube of 8-inch diameter and a LYSO scintillation crystal mounted in the centre of the tube. The scintillation light produced after the impact of a photoelectron which was accelerated to about 20 keV energy is read out by a small standard PMT. In addition to the attractive characteristics already established with its historic predecessors, namely high gain, large collection efficiency and immunity to the earth magnetic field, the X-HPD concept leads to very high effective Q.E. values, an extended viewing angle and marginal transit time spread. We present recent results obtained with 2 prototype tubes built at CERN in collaboration with the company Photonis.

Speaker: Christian Joram (CERN)

Paper joram.pdf (Protected)

Slides Joram_XHPD.ppt.ppt

17:50 Scintillation detectors for operation in high magnetic fields: recent developments based on arrays of avalanche microchannel photodiodes

The development of scintillation detectors to be used in a high magnetic field environment requires novel photodetectors to substitute photomultiplier tubes (PMTs). Avalanche microchannel photodiodes (AMPDs) are competitive to PMTs in terms of gain and photon detection efficiency and insensitive to magnetic fields. In this work we use AMPD arrays to build fast timing and large area detectors with promising characteristics.

Speaker: Robert Scheuermann (PSI)

Paper scheuermann.pdf (Protected)

Slides Presentation_VCI2007_Scheuermann.pdf Presentation_VCI2007_Scheuermann.ppt

18:30 → 20:00 Welcome Cocktail Party

Tuesday 20 February

09:00 → 12:35 Session 3

09:00 New developments in gaseous detectors

Almost one century after its origin, and thirty years after the invention of the Multi-Wire Proportional Chamber, the field of gaseous detectors is far from being fully exploited. With the increasingly stringent constraints of modern experiments, particularly concerning high rate capability and radiation resistance, spatial resolution and homogeneity of large sensitive area detection, a large research effort is devoted to the improvement and optimization of existing devices and the development of new more powerful concepts for radiation detection. The recent results in the field of gaseous detectors - used for particle physics and astrophysics research, space instrumentation, synchrotron radiation, biology and medical applications, with focus on design principles, performance, reliability and limitations - will be discussed. Novel structures where micropattern detectors are directly coupled to pixelized readout electronics may open novel detection possibilities in high energy physics and medical imaging. Finally, this talk will also highlight the main achievements in the field of gas detectors and will review the most promising directions in future developments and applications.

Speaker: Maxim TITOV (Freiburg University)

Paper titov.pdf (Protected)

Slides 1_Titov.pdf 1_Titov.ppt

09:55 First experience with the ATLAS Muon Spectrometer

The ATLAS experiment at the Large Hadron Collider (LHC) at CERN is currently being assembled to be ready to take first data in fall 2007. Its muon spectrometer is designed to achieve a momentum resolution of better than 10% at pμ = 1 TeV. The spectrometer consists of one barrel and two endcap superconducting air-core toroid magnets and is instrumented with three layers of Monitored Drift Tube chambers (Cathode Strip Chambers in the extreme forward region) as precision detectors. Resistive Plate Chambers in the barrel and Thin Gap Chambers in the endcap regions form a dedicated trigger system. We report on our experience with the commissioning and installation of the precision and trigger chambers. First results of the cosmic ray test of the barrel muon spectrometer with and without magnetic field are presented, including results of the calibration of the MDT chambers and the spectrometer alignment.

Speaker: Joerg Dubbert (MP-Inst. f. Physik, Munich)

Paper dubbert.pdf (Protected)

Slides vci_2007_jdubbert.pdf

10:20 First results of the CMS muon system using the 2006 cosmic runs of the magnet test

During summer 2006 the solenoid magnet of CMS was tested for the first time at its nominal field of 4T with a slice of each sub-detector operational. The first results and lessons learned with the cosmic runs taken in this configuration will be presented here with emphasis in the muon system. The magnet test has provided a unique opportunity to demonstrate the combined operation of CMS components from Magnet, Detector, Control Systems, Trigger, DAQ, Software and computing to allow early identification of problem areas and solutions one year before the actual LHC operation.

Speaker: Maria Chamizo Llatas (Cent.de Investigac.Energeticas Medioambientales y Tecnol. (CIEMAT))

Paper chamizo-llatas.pdf (Protected)

Slides 3_llatas.pdf

10:45 Coffee break

11:20 Commissioning of the ALICE TPC

The Time Projection Chamber (TPC) is the main tracking detector of the heavy ion Experiment ALICE at the CERN Large Hadron Collider (LHC). The field gage manufactured of carbon fiber composites has a total volume of 95 m 3, the readout chambers instrument the two end-plates of the TPC cylinder with an overall active area of 32.5 m 2. The detector covers the pseudorapidity range |η| < 0.9 and is optimized to be operated in a high multiplicity environment. The TPC has now been fully assembled and is undergoing commissioning with cosmic rays and tracks produced by a UV laser system. The system comprises a custom-designed electronic read-out based on a low noise preamplifier/shaper chip, and a digital circuit with a 10- bit 10-Msps ADC integrated into one chip for all 560000 read-out channels. We will report on the status of commissioning including analysis of the quality of track reconstruction and results on drift velocity, electron diffusion and position resolution of the tracking chambers as well as on the overall performance parameters of the detector.

Speaker: Ulrich Frankenfeld (GSI Darmstadt)

Paper frankenfeld.pdf (Protected)

Slides slides

11:45 RPC trigger counter cosmic ray tests in the ATLAS experiment

Extensive tests with cosmic rays have been performed with RPC trigger chambers installed in sector 13 of the ATLAS muon spectrometer. We illustrate the effort and report the results of this pre-commissioning phase, which rappresent a test bench to address the final commissioning of ATLAS RPC by cosmics rays. The tests done are mainly concentrated to establish a set of software and analysis tools necessary to debug and to understand the detector performance, mainly in term of noise, cluster size, and efficiency. Nevertheless, the data, taken with and without the toroidal magnetic field, have a quality high enough to allow a first detector characterization.

Speaker: Gabriele Chiodini (INFN Lecce)

Paper chiodini.pdf (Protected)

Slides 5_chiodini.pdf 5_chiodini.ppt

12:10 Ageing Phenomena in the LHCb Outer Tracker

The LHCb experiment is a single arm spectrometer, designed to study CP violation in B-decays at the Large Hadron Collider (LHC). It is crucial to accurately and efficiently detect the charged decay particles, in the high- density particle environment of the LHC. For this, the Outer Tracker (OT) is being constructed, consisting of ∼55,000 straw tubes, covering in total an area of 360 m 2 of double layers. The detector is foreseen to operate under large particle rates, up to 100 kHz/cm per straw in the region closest to the beam. Despite extensive ageing tests conducted earlier on with the aid of test-modules, a degradation of the gas gain has been found in the mass- production modules under a rather modest level of radiation. This paper presents the observed phenomenon, together with ongoing investigations to both prevent the effect, as well as to repair the gain loss.

Speaker: Tanja Haas (Phys. Institut Heidelberg)

Paper haas.pdf (Protected)

Slides wien2007_agingOTLHCb.pdf

12:35 → 14:00 Lunch Break

14:00 → 18:30 Session 4

14:00 Detectors for neutron scattering and synchrotron radiation

Neutrons and X-rays are two of the most important probes in studies of materials and physical phenomena. Throughout the world, major user facilities with beams of ever-increasing intensity of both types of radiation have been constructed or planned in recent years. This has created a need for neutron and Xray detectors with greater sophistication and higher counting rate capability. A few of these key developments will be discussed here. In neutron scattering, much of the demand is for larger area coverage, which has chiefly been provided by innovative 3He detectors or scintillator- based detectors. Some developments with 3He detectors operating in ionization mode are especially promising. For synchrotron studies, detectors utilizing conversion in noble gases are now less frequently used, but still have niche applications. There has been a significant increase in the routine use of silicon as an X-ray converter, particularly silicon detectors with high numbers of pixels. Some of these detector developments will be described, with examples from elemental microprobe instruments, Xray protein crystallography, and extended absorption fine structure studies.

Speaker: Graham Smith (BNL)

Slides IT4_VCI2007_GS.pdf IT4_VCI2007_GS.ppt

14:50 Micromegas TPC studies at high magnetic fields using the charge dispersion signal

The Time Pro jection Chamber (TPC) for the International Linear Collider (ILC) will measure about 200 track points with a resolution close to 100 μm. A Micro Pattern Gas Detector (MPGD) readout TPC may achieve the target resolution with existing techniques using 1 mm or narrower pads at the expense of increasing the detector cost and complexity. The new MPGD readout technique of charge dispersion has the potential to achieve good resolution without resorting to narrow pads. This has been demonstrated with 2 mm × 6 mm TPC readout pads for the GEMs and the Micromegas in cosmic ray tests and in a beam test at KEK in a 1 T magnetic field. The charge dispersion readout concept has been tested for the first time in a high field super-conducting magnet at DESY using a Micromegas-TPC. The measured Micromegas gain has been found to be constant within 0.5% for magnetic fields up to 5 T. The measurement results and the TPC resolution performance for cosmic rays at high magnetic fields will be presented.

Speaker: David Attie (CEA Saclay)

Paper attie.pdf (Protected)

Slides 070220_D.Atti?_VCI2007.ppt

15:15 Performance of MPGD-based TPC Prototypes for the Linear Collider Experiment

Time projection chamber (TPC) is considered as a strong candidate for the central tracker at the future linear collider experiment because of its large volume coverage and high three-dimensional granularity. Since the performance of TPC depends on its readout scheme we have conducted a series of experiments in order to compare the performance of prototype TPCs equipped with different readout planes: a conventional multi-wire proportional chamber (MWPC) or micro pattern gas detectors (GEM and MicroMEGAS), using common field cage and readout pad plane. The prototypes, filled with an argon-based gas mixture at the normal pressure, were subjected to a test beam at KEK under an axial magnetic field of up to 1 tesla. All the prototypes operated stably and provided us with valuable information. It was found that the obtained spatial resolution was reproduced both by an analytic formula and a MonteCarlo simulation with appropriate assumptions on the pad response function and the relative variance of avalanche fluctuation for a single drift electron. We report here the results obtained with MPGDs along with experimental details. Also included are the comparison between GEM and MicroMEGAS, interpretation of the results and extrapolation to the real TPC.

Speaker: Makoto Kobayashi (KEK)

Paper kobayashi.pdf (Protected)

Slides VCI2007_kobayashi_KEK.ppt

15:40 Coffee Break & Poster Session A

16:30 New GEM Detectors for Tracking and Triggering

Since its introduction in 1996 GEM (Gas Electron Multiplier) has attracted a lot of interest due to many promising features: good position accuracy and two track resolution, high rate capability, high radiation tolerance and time stability, large flexibility of the geometrical shapes and readout schemes. This has led to a wide range of applications from simple tracking and triggering through photon detection for fast RICH to GEMbased TPC. CERN was one of the main drivers behind these developments. In parallel to the success of GEM in physics experiments industrial partners became aware of their potential for applications in medicine, biology and safety technology. In this paper we show latest CERN developments of the new GEM detector configurations and readout structures. In particular we present detector developed for TOTEM using specific readout electrode allowing for precise tracking and fast triggering at the same time. As another example we present semi cylindrical detector developed for NA49-future experiment. Laboratory and beam test results illustrate detector performances.

Speaker: Leszek Ropelewski (CERN)

Slides 4_Ropelewski.ppt

16:55 A Triple-GEM Detector with Pixel Readout for High-Rate Beam Tracking

For its physics program with a high-intensity hadron beam of 2·10 7 particles/s, the COMPASS experiment at CERN requires tracking of charged particles scattered by very small angles with respect to the incident beam. While good resolution in time and space is mandatory, the challenge is imposed by the high beam intensity, requiring radiation hard detectors which add very little material to the beam path in order to minimize secondary interactions. To this end, a set of triple-GEM detectors with pixel readout in the beam region and 2-D strip readout in the periphery is being built. The pixel size has been chosen to be 1×1 mm 2, which constitutes a compromise between spatial resolution and number of readout channels. Peripheral to the pixel area, a 2-D strip readout with a pitch of 400 μm has been realized on the same printed circuit. In total an active area of 10×10 cm 2 is covered using 2048 readout channels. An analogue readout via the APV25-S1 ASIC has been chosen to profit from amplitude measurements on neighboring strips or pixels during clustering. A detector prototype has been tested successfully in the 5 · 10 7 μ/s COMPASS muon beam, as well as in a focused hadron beam. The design of the detector and first results concerning its performance as a beam tracker will be presented.

Speaker: Florian Haas (Technische Universitat Munchen)

Slides talk_vci_2007_fhaas.pdf

17:20 Two-phase avalanche detectors based on gas electron multipliers

The performances of two-phase Ar and Xe avalanche detectors were studied, aiming at their potential application in low-background experiments, such as those of coherent neutrino-nucleus scattering and dark matter search. The two-phase avalanche detector had a liquid Ar or Xe layer and a triple-GEM multiplier operated in the saturated vapour above the liquid phase. The suc- cessful operation of the two-phase Ar avalanche detector in a single electron counting mode, in the gain range of 6000-40000, has been demonstrated. The gain and stability characteristics were measured. The detector was shown to be sensitive to weak signals produced by nuclear recoils from neutron scat- tering and by 60 keV gamma-rays. The detection of the scintillation signal produced in the liquid by beta-particles and gamma-rays is provided in the two-phase Ar avalanche detector, the first GEM acting as a photocathode.

Speaker: Denis Pavlyuchenko (Budker Inst. Novosibirsk)

Paper pavluchenko.pdf (Protected)

Slides Pavlyuchenko_Vienna07_II.ppt

17:45 Three-dimensional reconstruction of single-electron clusters in a gaseous detector read out by the TimePix pixel circuit

In recent years the detection of minimum ionising particles in a gaseous detector by means of a CMOS pixel readout circuit as direct anode, has been demonstrated. Sofar the used pixel circuitry provided only a 2-dimensional projection of the position of the primary ionisation clusters. In the newly developed TimePix chip, based on the earlier used Medipix2 chip, each pixel also has the capability to record the arrival time of the detected single electrons. We present initial 3-dimensional reconstruction results from a small drift chamber, equipped with the TimePix chip as active anode. The readout chip is covered by a Micromegas foil to form a parallel-plate amplification gap.

Speaker: Jan Timmermans (NIKHEF Amsterdam)

Slides timmermans_vienna3.pdf timmermans_vienna3.ppt

18:10 Development of innovative micropattern gaseous detectors with resistive electrodes and first results of their applications

Recently developed micropattern gaseous detectors open new avenues in the detectors technology. However, due to the fine structure of their electrodes, these detectors are quite fragile and can be damaged by sparks. We have developed and successfully tested several prototypes of micropattern gaseous detectors based on a new design in which the cathode or the anode (in some case both of the electrodes) are coated by thin or thick resistive layers. These resistive coatings protect the detector and the front-end electronics in the case of sparks and thus make the detectors more robust and reliable. For example, an array of anode micropins each positioned in the centre of the microholes drilled in a thin resistive cathodes plate could operate either in proportional mode (at gains of up to 105 ) or in a streamer mode with an efficiency close to 100% for detection of x-ray photons. We also investigated the possible application of such detectors combined with CsI photocathodes to the detection of UV photons. The results of systematic studies of the characteristics of these detectors including rate capability and a long-term stability under the harsh conditions will be presented. Finally, we will present the first results of their applications to high energy physic and X-ray imaging.

Speaker: Vladimir Peskov (KTH Stockholm)

Paper peskov.pdf (Protected)

Slides Peskov-Vienna.pdf Peskov-Vienna.ppt

19:30 → 22:00 Soirée musicale

Wednesday 21 February

09:00 → 12:45 Session 5

09:00 Semiconductor detectors in high luminosity environment

As the final touches are being put to the LHC detectors, the race is on to per- fect technologies which could be used to confront the challenges of the ultra high luminosities at the SLHC and ILC. The achievements of the current de- tectors must be extended, with ever more hostile radiation environments, ever shorter signal shaping times and ever increasing emphasis on the highest possi- ble granularity combined with the lowest possible mass. In the semiconductor detector field, dedicated studies have identified many mechanisms behind ra- diation damage and pointed the way towards the use of new techniques such as MCz silicon and p-type sensors. In the most extreme environments, com- pletely new approaches, such as the use of diamond, or 3D sensor technologies will be essential. Pixel technology, which has been successfully employed to build large scale vertex detection systems for the LHC, will be pushed towards higher density, lower mass and greater integration, to satisfy in particular the ILC requirements. I will review the highlights of the current generation of semiconductor detectors and discuss some of the exciting prospects for future developments.

Speaker: Paula Collins (CERN)

Paper collins.pdf (Protected)

Slides 1_collins.ppt

09:50 The CMS Pixel Detector

The Compact Muon Solenoid Experiment (CMS) will start taking data at the Large Hadron Collider (LHC) in 2007 with the largest silicon tracking detector ever built. As a key component of this tracker, the collaboration is building a silicon pixel detector consisting of two forward/backward disks on each side of the interaction region and three barrel layers. The pixel detector will be crucial to pattern recognition and track reconstruction in the hadronic collisions of CMS and will play a key role in the physics program of the LHC. During the 2007 pilot physics run of the LHC, CMS will run with a subset of the final detector to be installed in 2008. The construction, testing and qualification of the pixel detector is an important aspect of the project and will be described in a separate contribution. In this report, the final design and results from test beam runs and expected performance of the detector are given. The expected radiation tolerance and projected lifetime of the pixel detector will be discussed as well its impact on the physics program of CMS.

Speaker: Aaron Dominguez (University of Nebraska)

Paper dominguez.pdf (Protected)

Slides CMS_Pixels.pdf

10:15 Status of the ALICE Silicon Pixel Detector

The Silicon Pixel Detector (SPD) forms the two innermost layers of the ALICE Inner Tracking System (ITS). The SPD consists of 120 detector modules (halfstaves) on two barrel layers at average radii of 3.9 cm and 7.6 cm, respectively. Each half-stave contains two ladders, each ladder consisting of a 200 μm thick p +n silicon sensor matrix flip-chip bonded to five 150 μm thick front-end chips. Each chip contains 8, 192 readout cells arranged in 256 rows and 32 columns with dimensions 50 μm (rφ) x 425 μm (z). The SPD contains nearly 10 7 pixel cells in total. The SPD provides the high spatial precision, efficiency and granularity required to reconstruct secondary vertices of charm and beauty meson decays in a region where the track density could reach 80 tracks/cm 2. The status of the construction and integration of the SPD will be overviewed. Results on the detector performance and its implementation in the ALICE simulation framework will be also discussed.

Speaker: Romualdo Santoro (INFN+Uni Bari)

Paper santoro_paper_figures.zip (Protected) santoro.pdf (Protected)

Slides Santoro_VCI07_full_ver.ppt

10:40 Coffee Break & Poster Session B

11:30 System test for the ATLAS Pixel Detector

The ATLAS Pixel Detector is an 80 M channels silicon tracking system designed to detect charged tracks and secondary vertices with very high precision. To verify that the integrated assembly will perform as expected subsequent to installation into the experimental area, a fraction (10%) of the detector and the requisite ancillary services has been assembled and operated in a laboratory setting. We refer to this as system testing, and results from these tests will be presented. The talk will illustrate all the aspects of the system test, including the detector control and safety system, the monitoring system and the DAQ system the data base technologies used to store the configuration and condition data, the techniques for calibrating the detector and the analysis of noise tests and cosmic data.

Speaker: Mauro Donega (Universite de Geneve)

Paper donega_paper_figures.zip (Protected) donega.pdf (Protected)

Slides 4_Donega.pdf

11:55 Design and Production of the LHCb Silicon Tracker

The LHCb Silicon Tracker covers a sensitive surface of about 14 m 2 with silicon micro-strip detectors. It uses up to 132 cm long detector modules with readout strips of up to 38 cm in length and up to 57 cm long Kapton interconnects in between sensors and readout chips. This results in large load capacitances for the front-end amplifiers and an extensive R&D programme was carried out to demonstrate that good S/N performance can be achieved despite the fast signal shaping times required for operation at the LHC. The production of detector modules is coming close to its completion. Special emphasis has been put on module quality assurance at all stages of the production. Various tests are performed after each production step and each module goes through several burn-in cycles lasting several days each. In my contribution, I will briefly describe the detector design, give a short overview of the main results from R&D and then concentrate on our experience from module production and quality assurance.

Speaker: Olaf Steinkamp (Uni Zurich)

Paper steinkamp.pdf

Slides VCI2007_Steinkamp.pdf

12:20 Status of the CMS Silicon Tracker and cosmic test results

With a total area of more than 200 square meters and about 15,000 silicon modules, the Tracker of the CMS experiment at the Large Hadron Collider will be the largest silicon strip detector ever built. Together with a Pixel detection system the CMS Silicon Strip Tracker will determine the charged particle momenta and will play a determinant role in lepton reconstruction and heavy flavor quark tagging. The Silicon Strip Tracker is at present being integrated and will be completed in spring 2007. In this paper, after a brief overview of the of the CMS Tracking System (Pixel and Strips Systems) we will describe the status of integration, the complex operations and tests that we are carrying out for the final commissioning of the detector. In the presentation results from the integration of the individual sub-detectors (Inner, Outer and Endcap) will be shown. Test results of such large structures will provide clear idea of the excellent system performance that can be achieved after the Tracker is installed and operated in CMS. In addition we will report on the recent CMS Magnet Test Cosmic Challenge (MTCC). Besides the very important commissioning of the Magnet System, this test has provided an ideal opportunity to test the global DAQ readout of a CMS slice under operating conditions, to test installation, operations and maintenance procedures. Approximately 25 million cosmic muon events were collected, of which 10 million events were collected with a magnetic field of up to 4 Tesla. Detailed Tracker performance, detector alignment and tracking studies are now being performed and will be shown.

Speaker: Gian Mario Bilei (INFN Perugia)

Slides 6_Bilei.ppt

12:45 → 14:00 Lunch Break

14:00 → 18:30 Session 6

14:00 Construction of the CMS silicon strip tracker

In the last year the CMS experiment has constructed and integrated the largest ever build full silicon strip tracker. Therefore the CMS tracker collaboration set up a unique scheme of quality control to ensure the necessary high quality of all of the 15,148 modules and their super structures. The applied scheme of quality control revealed several problems, which escaped the initial R&D phase, ranging from corrosion effects on the silicon, capton and via problems on the front end hybrids up to aging conductive glue. An overview of the construction and qualification experience is given, discussion the ma jor steps which result in the unique experimental device, which the CMS tracker is currently commissioning.

Speaker: Guido Heinrich Dirkes (Institut fuer Experimentelle Kernphysik)

Paper dirkes.pdf (Protected)

Slides VCI_GuidoDirkes.ppt

14:25 Commissioning of the ATLAS Semiconductor Tracker with Cosmic Rays

The Semiconductor Tracker(SCT) of the ATLAS detector enters the last phase of installation and commissioning at CERN. Prior to inserting into ATLAS, the barrel part of the SCT has been integrated with the Transition Radiation Tracker (TRT) barrel and tested with cosmic rays. A sector of 468 SCT modules has been powered and read simultaneously with TRT modules in physics mode. In total 500 thousand events were recorded during cosmic runs and processed with the ATLAS off-line reconstruction software. The SCT performance was measured in terms of the average noise occupancy per channel (4.5 ∗ 10 −5), the overall efficiency (> 99%). The tests with cosmic rays proved full functionality of the complex Detector Control System(DCS) which provides control, monitoring and safety functions for the detector electronics. The results of SCT barrel tests with cosmic rays will be presented as well as operational experience of running the fully integrated silicon detector during the commissioning of the completed SCT.

Speaker: Ewa Stanecka (Henryk Niewodniczanski Institute of Nuclear Physics PAN)

Paper stanecka.pdf (Protected)

Slides ESVienna.ppt

14:50 The CDF Silicon Detector: Performance and Longevity

The CDF silicon vertex detector is one of the largest operating silicon detectors in particle physics. Its silicon sensors have 722,432 channels read out by 5,456 chips and cover an area of 6 m 2. The detector is used for precision tracking and in the hardware trigger for events with a displaced vertex. It is very important for a success of the CDF physics program. The silicon detector has played a critical role in the first measurement of the B s mixing. This presentation includes a brief review of the detector performance and mainly focuses on issues of longevity and effects of radiation damage. This is of particular importance as the CDF experiment will be operating until the end of Tevatron Run II in 2009, with an expected integrated luminosity of 5–8 fb −1, which exceeds the initial design goal for the detector to be radiation hard for operation with a delivered luminosity of up to 3 fb −1. We present a detailed analysis of the time evolution of bias currents, depletion voltages, and signal-to-noise ratios, which indicate that the CDF silicon detector should outlast Run II without major degradation of performance.

Speaker: Alexandre Pronko (FNAL)

Paper pronko_paper_figures.zip (Protected) pronko.pdf (Protected)

Slides pronko_vci07_CDFsilicon.ppt.ppt

15:15 Development of Carbon Nanotube radiation detectors

Carbon Nanotubes are one-dimensional structures with diameters ranging between 2 and 100 nm and lengths up to hundreds of microns. They are characterized by a large variety of peculiar characteristics such as a semiconductive or metallic behaviour, a ballistic electrical conductivity and enhanced field emission capabilities. Among these characteristics their sensitivity to the radiation is very peculiar depending from their diameter and chirality. The energy gap varies from 0.4 to 6 eV leading to a sensitivity to the electromagnetic radiation, potentially from UV to IR. This opens the possibility to build a wide sensitive range radiation detector for space researches and environmental controls. Main characteristics of Carbon Nanotubes allowing the detection of radiation will be reported together with first results obtained exposing first prototypes to UV, visible and IR radiation.

Speaker: Michelangelo Ambrosio (INFN Napoli)

Slides 4_Ambrosio.pdf 4_Ambrosio.ppt

15:40 Coffee Break & Poster Session A

16:30 RD50 Status: Developing radiation tolerant materials for ultra rad-hard tracking detectors

The need for ultra-radiation hard semiconductor detectors for the tracker regions in high energy physics experiments at a future high luminosity hadron collider like the LHC Upgrade has led to the formation of the CERN RD50 collaboration. The R&D directions of RD50 follow two paths: understanding radiation effects, and finding mitigation through the use of new materials, device engineering and optimized operations, all of which will be covered in this paper. We will compare recent data on charge collection in new materials with electrical characterization, and show the effects of trapping, loss of full depletion and leakage current as a function of accumulated fluence of hadrons. An emerging picture of how a future tracking detector might look like will be presented.

Speaker: Richard Bates (Glasgow University)

Paper bates_paper_figures.zip (Protected) bates.pdf (Protected)

Slides RD50ViennaTalk.ppt

16:55 Signal and Charge Collection Efficiency of a p-type 3D-Detector irradiated to sLHC-Fluences, read out with 40 MHz

In view of the projected luminosity upgrade of the LHC, we are studying novel Silicon detectors in terms of their radiation-hardness to be employed as tracking detectors at the sLHC. We have tested 3D-detectors of singletype-column (STC) design, with only n-type columns etched into a p- type substrate. Rows of the columns are connected together to form strips. Using ATLAS SCT electronics, we have built prototype detector modules which were then irradiated to a dose of up to 10 15N eq/cm 2. After irradiation, the modules were tested with two methods: a β-source set-up and an IR-laser. The former allows measurements of the absolute CCE and Signal, whereas the laser yields only relative results, though with high position resolution. Position-sensitive measurements are required, as from simulation the STC 3D-detector geometry is expected to have low-field regions with lower CCE. We will report on the performance of the irradiated 3D-modules read out at 40 MHz, compare it to the un-irradiated behaviour, and draw conclusions about the feasibility of using such detectors for tracking at the sLHC.

Speaker: Simon Eckert (Universität Freiburg)

Paper eckert.pdf (Protected)

Slides Vienna_3D_final.pdf

17:20 Development of CMOS sensors for future high precision sensitive detectors

CMOS sensors are being developed for various position sensitive detectors requiring high granularity and low material budget, together with relatively fast read-out and good radiation tolerance as well as low power dissipation. A review of the charged particle detection performances achieved with sensors of the MIMOSA series will be provided, emphasizing preliminary test results of chips developed for the beam telescope of the EUDET programme (E.U.FP6) to be commissionned in 2007, and for the 2008 vertex detector upgrade of the STAR experiment at RHIC. Beyond these short term applications, MIMOSA sensors are being developed for detectors requiring 10 to 100 times faster read-out: final EUDET beam telescope (2009), ultimate STAR upgrade (2011), CBM experiment at FAIR/GSI (

Speaker: Wojciech Dulinski (IReS Strasbourg)

Slides dulinski_VCI.pdf dulinski_VCI.ppt

17:45 Silicon Drift Detectors for the kaonic atom X-ray measurements in the SIDDHARTA experiment

Silicon Drift Detectors (SDDs) are X-ray detectors with the outstanding performance for the measurement of the kaonic atom X-ray lines. The measurement of the kaonic hydrogen/deuterium X-rays with a high background suppression is a crucial issue, because of the small X-ray yields (a few % in kaonic hydrogen and much smaller in kaonic deuterium) and high background usually accompanying the available kaon beams. Large- area SDDs are being developed for the kaonic X-ray measurements in the SIDDHARTA experiment at LNF (Italy). The SDDs will provide an excellent background suppression using the time correlation between the kaonic X- rays and the back-to-back correlated K +K− pairs produced by the DAΦNE electron-positron collider. This first application of these SDDs is an innovation for X-ray spectroscopy in general, and for the kaonic atom X-ray measurements in particular. The Xray energy and width of the kaonic hydrogen Kα line will be determined most accurately, and the kaonic deuterium Kα line will be measured for the first time. In this talk, the experimental method to measure the kaonic X-rays with the SDDs is presented as well as a comparison with the CCD X-ray detectors used in the previous experiment.

Speaker: Tomoichi Ishiwatari (Stefan Meyer Institut f. subat. Phys., Wien)

Paper ishiwatari.pdf (Protected)

Slides vci2007-ishiwatari.pdf vci2007-ishiwatari.ppt

18:10 R&D for a monolithic pixel sensor based on 150 nm fully-depleted SoI CMOS technology

The effort to develop a monolithic pixel sensor based on the SOI (silicon on insulator) CMOS technology is presented. In SOI, MOS transistors are produced on silicon oxide layer (BOX) above a silicon substrate. A monolithic pixel detector is realized if we adopt a high-resistivity silicon and p-type and n-type implantations can be made in the substrate. The charge induced in the substrate by photons or charged particles is processed by the CMOS circuit above the BOX. In 2005, an R&D has started based on fully-depleted SOI of OKI Electric Industry Co. Ltd. and several types of TEG were fabricated and tested. We present the basic characteristics of the SOI technology, properties of the high-resistivity substrate and its functionality, and, test results of TEGs including a 32x32 matrix pixel detector, which successfully detected small signals for laser light and a β source. Finally, we cover the prospect of 2007 R&Ds.

Speaker: Toru Tsuboyama (KEK)

Paper tsuboyama.pdf

Slides Tsuboyama-SOI.pdf.pdf

Thursday 22 February

09:00 → 12:45 Session 7

09:00 Calorimeters for collider experiments

Structured granular calorimeters play a central role in all modern collider experiments. Calorimeter technologies are strongly motivated by both the physics goals and general concept of particular detector. This paper reviews the status of the LHC calorimeters which have been successfully constructed and presently are in the stage of commissioning. The calorimeters planned for future pro jects, such as ILC, super B-factory and FAIR at GSI, are discussed as well.

Speaker: Andrey GOLUTVIN (ITEP Moscow)

Slides Calorimeters_comp.ppt

09:50 The Atlas Liquid Argon Calorimeter: Integration, Installation and Commissioning

The ATLAS liquid argon (LAr) calorimeter system consists of an electromagnetic barrel calorimeter and two endcaps with electromagnetic, hadronic and forward calorimeters. The liquid argon sampling technique, with an accordion geometry was chosen for the barrel electromagnetic calorimeter (EMB) and adapted to the endcap (EMEC). The hadronic endcap calorimeter (HEC) is using a copper-liquid argon sampling technique with flat plate geometry and is subdivided into two wheels in depth per end-cap. Finally, the forward calorimeter (FCAL) is composed of three modules featuring cylindrical electrodes with thin liquid argon gaps.

Speaker: Mohamed Aharrouche (LAPP-Annecy)

Paper aharrouche.pdf (Protected)

Slides Aharrouche_VCI07.ppt

10:15 The Electromagnetic Calorimeter of the CMS Experiment

The Large Hadron Collider will allow the study of pp interactions at a center of mass energy of 14 TeV. The main physics goals of the CMS experiment are the discovery of the Higgs boson and the search for new physics phenomena, in particular the appearance of particles predicted by Supersymmetric theories. The Electromagnetic Calorimeter of the CMS experiment is made of 75848 Lead Tungstate scintillating crystals. This challenging project aims to achieve an extreme precision in photons and electrons energy measurement. General motivations, main technical challenges, plans for commissioning and precise energy calibration, and the actual status of the project will be discussed.

Speaker: Marcella Diemoz (INFN Rom)

Paper diemoz.pdf (Protected)

Slides MD_ECAL_VCI_07.ppt

10:40 Coffee Break & Poster Session B

11:30 The neutron response of a Pb-scintillating fiber sampling calorimeter: Monte Carlo simulation and experimental validation

The KLOE Pb-scintillating fiber calorimeter, primarily designed as an electromagnetic calorimeter, showed a superior neutron efficiency in a measurement performed in the energy range [20,180] MeV at TSL (The Svedberg Laboratory, Uppsala) presented in a parallel contribution to this conference. A detailed simulation of the calorimeter - a complex geometrical structure of 200 layers of thin (0.5 mm) grooved lead foils and 1 mm diameter scintillating fibers glued inside - and of the main elements of the TSL beamline has been performed with the Monte Carlo code FLUKA. The simulated response of the calorimeter to neutrons, together with the experimental validation by the TSL data, is presented, showing a high neutron efficiency, which ranges between 40% and 50%. The reasons of a such enhancement of the efficiency, in comparison with the typical neutron counters, are investigated and discussed, opening to the possibility of a new, innovative neutron detector.

Speaker: Anna Ferrari (CNAO Milano)

Paper ferrari.pdf (Protected)

Slides slides VCI07_annaferrari.pdf

11:55 CALICE Silicon-Tungsten Electromagnetic Calorimeter - Concept and Test Beam Results

In 2006, the silicon tungsten calorimeter prototype developed by the CALICE Collaboration was irradiated by low energy electrons (< 6 GeV) at DESY and electrons and hadrons (pions and protons) of energies from 6 GeV to 50 GeV and 80 GeV, respectively, at CERN. Obtained data demonstrate superb shower patterns, determined mainly by a small Moliere radius of tungsten and fine granularity of silicon sensors. Such a calorimeter functions to a great extent as a tracker and meets requirements of particle flow concept for the analysis of e+e- collisions at future linear collider. The concept of the silicon-tungsten electromagnetic calorimeter, analysis of test beam results and characterisation of the calorimeter prototype which operated most of time in combination with the TileCal hadron calorimeter and tail catcher prototypes will be presented together with the outlook and future R&D plans towards the final calorimeter design.

Speaker: Vaclav Vrba (Czech Ac. of Sciences)

Slides VCI2007-VaclavVrba.pdf VCI2007-VaclavVrba.ppt

12:20 The PANDA Detector at FAIR

PANDA is a next generation hadron physics detector planned to be operated at the future Facility for Antiproton and Ion Research (FAIR) at Darmstadt, Germany. It will be using cooled antiproton beams with an energy between 1.5 GeV and 15 GeV interacting with various internal targets. The experiment is focusing on hadron spectroscopy, in particular the search for exotic states in the charmonium region, on the interaction of charm hadrons with the nuclear medium and on double-hypernuclei. With physics requiring precise partial wave analysis the experiment has almost 4π acceptance, a solenoid magnet for high pT tracks and a dipole magnet for the forward part of reaction products. A silicon vertex detector surrounds the interaction point. In both spectrometer parts tracking, charged particle identification, electromagnetic calorimetry and muon identification are available. The readout of all sub-detectors is fully self-triggering and event selection is performed online by programmable electronics and compute nodes to allow full flexibility and parallel physics data taking. The status of the detector development and the facility is presented.

Speaker: Lars Schmitt (GSI Darmstadt)

Paper schmitt.pdf (Protected)

Slides lschmitt_vci07.odp lschmitt_vci07.pdf

12:45 → 14:00 Lunch Break

14:00 → 18:30 Session 8

14:00 Comparision of different detector concepts for a linear collider

The International Linear Collider (ILC) is the next large project in high energy physics and currently being designed in a global effort. The main scientific goal is to complement the anticipated discoveries at the LHC by precision measurements at the TeV scale. This has challenging implications on the ILC detector design and performance requiring unprecedented precision in vertexing, tracking and calorimetry. Design studies on four detector concepts are ongoing which are complemented by international R&D programmes to develop detectors suitable for the conditions at the collider and matching the required performances. A survey will be given on the detector concepts and technologies under investigation together with the current status of the R&D programmes and future plans.

Speaker: Joachim MNICH (DESY)

Paper mnich.pdf (Protected)

Slides 1_Mnich.pdf 1_Mnich.ppt

14:55 Upgrade and Operation of the DO Central Track Trigger

The DØ experiment at the Fermilab pp Tevatron collider (Batavia, IL, USA) has undergone significant upgrades in anticipation of high luminosity running conditions. As part of the upgrade, the capabilities of the Central Track Trigger (CTT) to make trigger decisions based on hit patterns in the Central Fiber Tracker (CFT) have been much improved. We report on the implementation, commissioning and operation of the upgraded CTT system.

Speaker: Marc Buehler (University of Virginia)

Paper buehler.pdf (Protected)

Slides buehler_vci07_final.pdf

15:20 Timepix, a 65k programmable pixel readout chip for arrival time, energy and/or photon counting measurements

A novel approach for the readout of a TPC at the future linear collider is to use a CMOS pixel detector combined with some kind of gas gain grid. A first test using the photon counting chip, Medipix2, with GEM or Micromegas demonstrated the feasibility of such an approach. Although this experiment demonstrated that single electrons could be detected the chip did not provide information on the arrival time of the electron in the sensitive gas volume nor did it give any indication of the quantity of charge detected. The Timepix chip will use an external clock up to a 100 MHz as a time reference. In the new chip each pixel can record the particle arrival time with respect to an external shutter using the same 14-bit counter as used in the Medipix2 chip to record the number of particle arrivals during a shutter opening time. Moreover, each pixel can be independently configured in one of 4 different modes: masked mode: pixel is off; Medipix2 mode: 1-count for each signal over threshold, analog mode: the counter is incremented continuously as long as the signal is above threshold; and Timepix mode: the counter is incremented continuously from the time the first hit arrives until the end of the shutter. Each pixel contains a preamplifier, a discriminator with hysteresis and 4 bits of threshold adjustment, synchronization logic and a 14-bit counter with overflow control. The chip resembles very much the Medipix2 chip physically and can be read out using the various existing systems. The presentation will outline the main features of the new design, electrical measurements and a few first images.

Speaker: Xavier Llopart Cudie (CERN)

Paper llopart.pdf (Protected)

Slides XavierLlopart_VCI2007.pdf XavierLlopart_VCI2007.ppt

15:45 Coffee break

16:20 The AMS-02 Silicon Tracker: construction and performance

Eight layers of double sided silicon microstrip sensors embedded in a 0.8 T magnetic field constitute the core of the AMS-02 apparatus. In each layer, simultaneous measurements of position and energy loss in silicon are performed along the particle trajectory. With its high spatial resolution, the silicon tracker will determine the rigidity (R) and the charge sign of particles up to several TVs, with a relative resolution ∼ 2.5% at R < 100 GV. The low noise and wide dynamic range of the silicon readout electronics allow to exploit the energy loss measurements to determine the particle absolute charge for nuclei up to Fe. The AMS Tracker construction has been completed and it will be integrated into the AMS experiment during the 2007. The performance of the silicon detectors observed under various beam tests will be presented focusing on the spatial resolution and on the charge separation capability. The performance of the six inner planes, already integrated in the flight structure, with cosmic rays will also be presented.

Speaker: Giovanni Ambrosi (INFN Perugia)

Slides Ambrosi.pdf

16:45 PEBS - Positron Electron Balloon Spectrometer

The best measurement of the cosmic ray positron flux available today was performed by the HEAT balloon experiment more than 10 years ago. Given the limitations in weight and power consumption for balloon experiments, a novel approach was needed to design a detector which could increase the existing data by more than a factor of 100. Using silicon photomultipliers for the readout of a scintillating fiber tracker and of an imaging electromagnetic calorimeter, the PEBS detector features a large geometrical acceptance of 4000 cm^2 sr, a total weight of 1500 kg and a power consumption of 900 W . The experiment is intended to measure cosmic ray particle spectra for a period of up to 20 days at an altitude of 40 km circulating the North or South Pole. A full Geant 4 simulation of the detector concept has been developed and key elements have been verified in a testbeam in October 2006 at CERN.

Speaker: Henning Gast (RWTH Aachen)

Paper gast.pdf (Protected)

Slides Henning_VCI07.pdf.pdf

17:10 Construction and beam test of a dual layer silicon charge detector (SCD) for the CREAM experiment

The Cosmic Ray Energetics And Mass (CREAM) balloon-borne experiment is designed for direct measurement of high-energy cosmic-ray particles. The science goal is to measure the single-element fluxes of all cosmic-ray nuclei from hydrogen (protons) to iron with energies up to the ”knee”, or spectral index change, near 10 15 eV observed in the all-particle spectrum. A dual layer Silicon Charge Detector (SCD-II) was designed for precise charge measurement of incident nuclei. Each SCD-II layer consists of 26 ASIC boards and 182 silicon sensors covering an active area of 77.9 x 79.5 cm 2 . Each sensor is comprised of a 4 x 4 array of single-sided DC type silicon pixels with an active area of 2.1 cm 2 . The detector was launched as part of CREAM-II on December 16th, 2005, stayed at float for 28 days, and was recovered successfully. The SCD-II was refurbished for the 3rd CREAM flight planned for December 2007, and tested at CERN October 2006. The construction and the beam test results of the SCD-II are reported.

Speaker: Nahee Park (Ewha University)

Paper park.pdf (Protected)

Slides VCI2007_Feb22_CREAM_SCD_Nahee.ppt.ppt

17:35 Imaging with the invisible light

We report on a UV photo-detector with single electron sensitivity and excel- lent imaging capabilities. It is based on a semitransparent CsI photocathode followed by a Gas Electron Multiplier (GEM) foil and by a large area, cus- tom, analog, VLSI ASIC. The avalanche charge produced in a GEM hole is extracted and measured by the CMOS chip that is at the same time the pixelized charge collecting electrode and the amplifying, shaping and charge measuring front-end electronics of the Micropattern Gas Detectors (MPGD). The GEM foil and the VLSI pixel chip have matched 50μm pitch on a tri- angular pattern. Gas gain above 10^4 and single electron detection efficiency greater than 80% have been measured. The high granularity and low noise of the read-out plane allows to reconstruct with 4μm resolution the centroid of the single electron avalanche. This defines the intrinsic resolution of the read- out system. Thanks to this unique feature, excellent imaging capability has been demonstrated. The detector position resolution is at the moment limited by the 50μm pitch of the GEM foil. Charge multipliers with finer pitch will allow exploiting the much higher intrinsic resolution of the device.

Speaker: Ronaldo Bellazzini (INFN Pisa)

Paper bellazzini.pdf (Protected)

Slides VCI2007_Bellazzini.pdf VCI2007_Bellazzini.ppt

18:00 Gamma-ray imaging with a large micro-TPC and a scintillation camera

Following the successful astronomical observation by COMPTEL onboard GRO, a Compton telescope with higher performance is required. With COMP- TEL a direction of a recoil electron was not measured, so an origin of the incident photon could only be reconstructed to a cone. Measuring the direc- tion of recoil electron reduces the Compton cone to a segment of the cone, and realizes the strong background rejection. To measure the direction of the recoil electron, we have developed a micro-time pro jection chamber (micro- TPC) based on a micro-pixel chamber (μ-PIC). The scattered gamma-ray is measured using 30 cm ×30 cm NaI(Tl) scintillation camera. We developed a larger size micro-TPC (23 cm ×28 cm×15 cm) than previous prototype (10 cm ×10 cm×10 cm). In this presentation, we are reporting on the fundamental performances of the MeV gamma-ray camera.

Speaker: Kaori Hattori (Kyoto University)

Paper hattori.pdf (Protected)

Slides VCI2007_hattori.pdf VCI2007_hattori.ppt

20:00 → 22:30 Conference Banquete

Friday 23 February

09:00 → 12:35 Session 9

09:00 Detectors for particle identification

The paper will review recent progress in particle identification methods. After a survey of motivations and requirements for particle identification in various experimental environments, the main emphasis will be on the development of new ring imaging Cerenkov counters. A number of new techniques has emerged recently, from upgrades of existing devices to a novel focusing radiator concept and new photon detectors. The benefits will be discussed of including a precise measurement of the time of arrival of Cerenkov photons, from reducing the background level to the much more ambitious use in combined time-of-flight (TOF) or time-of-propagation counters. The paper will also discuss progress in dedicated TOF counters with recently developed very fast photon detectors.

Speaker: Peter Krizan (Univ. Ljubljana)

Paper krizan.pdf (Protected)

Slides vci07-krizan.pdf

09:55 The ATLAS Transition Radiation Tracker: from construction to assembly in the ATLAS cavern

The ATLAS experiment at LHC is now approaching the end of the construction phase. In this presentation, I will focus on the ATLAS-TRT (Transition Radiation Tracker) assembly and its installation in the ATLAS cavern, which covers the period of the last two years. After an overview of the TRT detector, I will show the various tests performed during the ”stacking” of the TRT wheels. This concerns mainly the leak tightness of the piping for the cooling and the active gas, the test of the high voltage distribution and the checking of the front-end electronics. Then, I show some results obtained in the combined test of two of the ATLAS trackers (SCT and TRT), and I conclude with the installation of the TRT in the ATLAS cavern.

Speaker: Franck Martin (University of Pennsylvania)

Paper martin.pdf (Protected)

Slides vienna2007.pdf vienna2007.ppt

10:20 High Counting Rate Transition Radiation Detector

A new Transition Radiation Detector (TRD) prototype with a high granularity for a high counting rate environment, required by the CBM experiment, at the future experimental facility FAIR - GSI Darmstadt, was designed and built. A solution for such a detector is a multiwire proportional chamber with a minimized drift region, reduced to a cathode - readout pad plane distance of 6 mm and a multiwire anode plane in the middle. Results of the 55Fe source tests and of the in-beam investigations of the rate capability in terms of signal deterioration and position resolution degradation with the increase of the counting rate, for different gas mixtures, applied voltages and anode configurations are presented. Based on the measured deposited energy spectra, the discrimination between electrons and pions as a function of number of layers was estimated by Monte Carlo simulations.

Speaker: Mariana Petris (IFIN-HH Bukarest)

Paper petris.pdf (Protected)

Slides hcrtrd_mariana_petris.pdf hcrtrd_mariana_petris.ppt

10:45 Coffee break

11:20 The LHCb RICH Detectors

The LHCb experiment has been optimized for high precision studies of CP violation and other rare decay phenomena in B-meson decays at the CERN LHC. Particle Identification (PID) in the momentum range from a few to ∼100 GeV/c is essential. Hadrons in this momentum range are identified by means of two Ring Imaging Cherenkov (RICH) detectors using Silica Aerogel, C4F10 and CF4 gas radiators. The RICH detectors will use Hybrid Photon Detectors (HPDs) to measure the position of Cherenkov photons over the wavelength range 200-600 nm. The HPDs have an 83 mm diameter quartz entrance window. Electrostatic focusing images the photocathode onto a pixelated anode sensor, bump-bonded to a read-out chip that is encapsulated in the tube vacuum. The anode has 1024 pixels providing 2.5 mm × 2.5 mm granularity at the photocathode and the addresses of hit pixels are read out at the LHC bunch crossing rate of 40 MHz.A total of 484 HPDs cover an area of ∼2.6 m 2 with ∼70% active area coverage. In this talk we describe the RICH detectors, the performance of the HPDs in laboratory measurements and tests using charged particle beams, and the calibration that the HPDs will require when operating in the LHCb detector. The status of the LHCb RICH detector construction and commissioning will be presented.

Speaker: Gabriel Vidal-Sitjes (Imperial College, London)

Slides G.Vidal-Sitjes_VCI2007.pdf G.Vidal-Sitjes_VCI2007.ppt

11:45 Experience from the construction and installation of the HMPID CsI-RICH detector in ALICE

The construction and installation phases of the High Momentum Particle IDentification detector (HMPID) of the ALICE experiment were completed by summer 2006. The HMPID has been designed to identify charged pions and kaons in the range 1 < pt < 3 GeV/c and protons in the range 2 < pt < 5 GeV/c. The total active area of this detector is 11 m 2 and represents the largest scale application of CsI photo-cathodes in RICH detectors. We will report on the production of the CsI photo-cathodes and their performances, the readout electronics, the mwpcs and the assembly and handling procedures needed to produce such a large detector. As well, we will present performance results achieved in test beams and the main difficulties encountered during the construction process.

Speaker: Abraham Antonio Gallas Torreira (Istituto Nazionale di Fisica Nucleare (INFN))

Paper gallas.pdf (Protected)

Slides Vienna_Gallas.ppt

12:10 The Fast Photon Detection System of COMPASS RICH-1

A fast photon detection system has been designed and built for the upgrade of COMPASS RICH-1, a large size gaseous RICH in use at the COMPASS Experiment at CERN SPS since 2001 and successfully operated in its upgraded version during the 2006 run. The aim of the upgrade was to make RICH-1 adequate for high rate operation: the photon detectors of the central region have been replaced by a new system based on MAPMTs coupled to individual fused silica lens telescopes and fast read-out electronics while in the peripheral regions the existing MWPCs with CsI photocathodes have been equipped with a new read-out system, based on the APV chip. The telescopes are characterized by a large image demagnification factor with minimal distortion and large angular acceptance. Accurate coupling to high sensitivity front-end electronics allowed overcoming the potential problem represented by the wide dynamical range of PMT responses to single photoelectrons, while keeping the noise rates and the channel cross-talk at a negligible level. The high rate capability and the good intrinsic PMT time resolution are fully exploited by signal digitization via a system based on the F1 TDC. We present the photon detection design and the constructive aspects, the test beam and laboratory studies, as well as the preliminary characterization of the system in the COMPASS experimental environment, where about 60 photons per ring at saturation have been routinely obtained. It will be shown that, with this upgrade, COMPASS RICH-1 is entering the era of the fast RICH counters, suitable for high rate operation.

Speaker: Fulvio Tessarotto (INFN Triest)

Paper tessarotto.pdf (Protected)

Slides tessarotto_VCI2007.pdf tessarotto_VCI2007.ppt

12:35 → 14:00 Lunch Break

14:00 → 18:00 Session 10

14:00 Modern detector and trigger electronics

The past two decades have provided a wealth of experience in highly integrated front-end electronics for high energy physics. The SLHC and ILC, however, pose formidable challenges, not so much to technology, but to optimum utiliza- tion of existing technology. The increased radiation load at the SLHC drives detectors to higher segmentation, which exacerbates the problems of reducing power and material. Vertex and tracking detectors at the ILC are driven by position resolution and material, also linked to power dissipation. Power con- straints also limit the readout rate, which affects the choice of trigger architec- tures. One path to more efficient trigger systems is the use of hardware trigger processors, which will become more powerful as the technology of FPGAs and other digital hardware progresses. Following a review of current systems, I will discuss various paths to attack these challenges.

Speaker: Helmuth Spieler (LBNL)

Paper spieler.pdf (Protected)

Slides VCI_2007_Spieler.pdf

14:55 Study of Proximity Focusing RICH with Silica Aerogel Radiator

Proximity focusing RICH based on silica aerogel Cherenkov radiator has been developed for new particle identification device in the Belle detector upgrade. To further improve detector performance, new concept for Cherenkov ring imaging has been introduced, where multiple aerogel layers with different indices are accumulated to increase detected photoelectrons without making a signle photon resolution worse. By constructing a prototype counter, this idea has been validated in a test beam experiment, and we achieved 5.5 σ π/K separation at 4 GeV/c with more than 9 photoelectrons.

Speaker: Ichiro Adachi (KEK)

Paper adachi.pdf (Protected)

Slides

• 2_adachi.pdf
• 2_adachi.ppt
• vci2007_adachi.pdf

15:20 Coffee Break

15:55 The Focusing DIRC - the first RICH detector to correct the chromatic error by timing, and the development of a new TOF detector concept

Benefiting form from the recent introduction of new fast vacuum-based pho- ton detectors with a transit time distribution of σ_TTS ∼ 30-150ps, we are developing novel RICH detector capable of correcting the chromatic error by timing, attempted the first time ever on such a scale; we are also developing a novel TOF detector concept. We have built and successfully tested a novel particle identification detector called Focusing DIRC. The prototype’s concept is based on the BaBar DIRC with several important improvements: (a) much faster pixilated photon detectors based on Burle MCP-PMT and Hamamatsu MaPMT, (b) mirror allowing to make the photon detector smaller and less sen- sitive to background in future applications, (c) electronics allowing to measure the single photon resolution to better than σ ∼ 100-200ps, which allows a cor- rection of the chromatic error. This is the very first time the chromatic error was corrected by this method. The detector was tested in the SLAC 10GeV electron test beam. The presented detector concept could be used for the par- ticle identification at Super B-factory, ILC, Gluex, Panda, etc. While testing the timing resolution limits of a 64-pixel MCP-PMT with 10 μm MCP holes, we have achieved a timing resolution of σ ∼ 30ps with single photoelectrons, and σ ∼ 8-9ps with for a large number of photoelectrons. This is the best re- sult ever obtained with this type of tube. The results were obtained with the PiLas laser diode and represent the point resolution response of the tube. We present a systematic timing resolution study for various timing concepts as a function of number of photoelectrons and the magnetic field. The presented TOF detector concept could be used for the particle identification at Super B-factory endcaps.

Speaker: Jerry Va'vra (SLAC)

Paper vavra.pdf

Slides 3_Vavra.pdf

16:20 Results from R&D of Cherenkov detectors at Novosibirsk

The work on aerogel Cherenkov counters was started in Novosibirsk in 1986. Our group produces silica aerogels with refractive indices of 1.006–1.13. Largest block dimensions achieved for n=1.03 are 200 × 200 × 50 mm^3. Optical transparency of Novosibirsk aerogel is one of the best in the world. The particle identification system for the KEDR detector based on the ASHIPH coun- ters with light collection on wavelength shifters has been partially installed in 2003. The system consists of 160 counters containing 1000 l of aerogel in the whole. The similar counters for the SND detector at VEPP-2000 e+e− collider are being developed. Aerogel with refraction index of 1.13 has been employed in this counters for the first time in the world. The results of the SND counter test with cosmic muons are presented. Recently we have started the study of RICH with ‘focusing aerogel’ (FARICH). We have developed a technique of multi-layer aerogel blocks production. A few samples of 2- and 4-layered aerogel were produced. The Geant4 simulation code has been de- veloped to calculate the performance of FARICH detector. The possibility of using crystal sodium fluoride in a RICH detector has been investigated. It has been shown that NaF RICH can achieve a competitive velocity resolution as compared to aerogel RICH. The combined NaF-aerogel radiator has been proposed to extend the working momentum range of aerogel RICH down to 0.6 GeV/c.

Speaker: Sergey A. Kononov (Budker Inst. Novosibirsk)

Paper kononov.pdf (Protected)

Slides kononov-talk-vci07.ppt

16:45 Liquid Xenon Gamma Ray Detector for MEG

MEG experiment is a rare muon decay search experiment. A muon rare decay μ + → e + γ violates lepton flavor conservation. The standard model predicts too small branching ratio to observe, however many new theories predict observable branching ratio. MEG experiment has sensitivity to the background ratio better than 10 −13 which is two orders of magnitude better than current experimental limit 1.2×10 −11. One feature of the experiment is a liquid xenon scintillation gamma ray detector. The detector consists of 800 litters of liquid xenon and 850 photo-multipliers. We performed beam tests to measure resolutions of the detector using prototype. MEG experiment starts physics data taking in 2007.

Speaker: Ryu Sawada (Uni Tokyo)

Paper sawada.pdf (Protected)

Slides sawada_slide_2.pdf

17:10 Summary Talk

Speaker: Fabio Sauli (CERN)

Slides CONFERENCE_SUMMARY.pdf CONFERENCE_SUMMARY.ppt

Saturday 24 February

09:00 → 13:10 Session 11

Applications

09:00 High-rate Photon Counting Imaging for Mammography at the SYRMEP Beam-line

During 2006 the SYRMEP (Synchrotron Radiation for Medical Physics) collaboration performed worldwide unique clinical mammographic examinations using X-rays generated by one of the bending magnets at the synchrotron radiation facility Elettra (Trieste, Italy). While these examinations have been performed with traditional screen-film systems, recently a major effort has been pursued in order to exploit the so-called phase contrast imaging with a monochromatic laminar high-rate X-ray beam in combination with a suitable digital detector. The INFN MATISSE project (Mammographic and Tomographic Imaging with Silicon detectors and Synchrotron radiation at Elettra) and the Paul Scherrer Institut have developed a digital detector based on a microstrip silicon sensor (50 μm pitch) coupled to the Mythen-II high-rate photon counting ASIC. This detector, which uses the edge-on technique to improve the detection efficiency, features a total of 2368 readout channels covering a beam width of about 12 cm. The system, which can be modeled as a paralyzing single photon counter, enables X-ray imaging at the quantum limit for photon fluence as high as 70 MHz/mm 2. This contribution presents the characterization of the device in terms of its detective quantum efficiency (DQE ) and the images of standard and lowcontrast phantoms recorded in standard absorption geometry and in the phase contrast imaging modality.

Speaker: Mr Erik Vallazza (INFN Triest)

Slides vci2007_vallazza.pdf

09:25 A Single Photon Emission Computer Tomograph for breast cancer imaging

We have developed a tomograph for single photon emission imaging (SPECT) of the breast for the detection of small size tumors. The patient is prone with a pendulus breast. The SPECT is mounted on a ring that is rotating around the breast. The breast will be imaged by two opposing detector heads of approximately 5x15 cm^2 each, with a field of view about 13 cm wide. Each head is made up of one pixilated NaI crystal matrix coupled to three Hamamatsu H8500 PMTs with a ''general purpose'' collimator. Detailed simulations have been made for the optimization and the evaluation of the detector performance, in terms of detection efficiency and geometric spatial resolution. Monte Carlo results indicate that tumors of 8 mm diameter are detectable with a tumour/background ratio of 5:1. First experimental results on planar images are presented. The rotating ring is now being assembled.

Speaker: Sara Vecchio (INFN Pisa)

Paper vecchio.pdf (Protected)

Slides Vecchio_VCI.pdf Vecchio_VCI.ppt

09:50 A scintillating fiber dosimeter for radiotherapy

Radiotherapy, together with chemiotherapy and surgery, is one of the main methods applied in the fight against cancer; in order to increase the chances of a successful radiotherapy treatment the dose delivery to the tumour areas and the surrounding normal tissues has to be computed with high accuracy. Standard dosimeters are accurate but too small (ionization chambers and diodes) or non real time (radiographic films). At present there is no device that can perform real time and bidimensional measurements of a dose distribution. This article will describe the development of a real-time dosimeter based on scintillating fibers for photon and electron beams (each one of few mm 3); the fibers are made of polystyrene, that is water equivalent and thus tissue equivalent, allowing a direct dose calculation. The small scintillators are inserted in a PMMA phantom; the light produced is collected by white fibers and readout by a multichannel photomultiplier tube. Several prototypes (single and multi channel) have been assembled; they have passed successfully the tests of reliability, linearity response and comparison with standard dosimeters. The paper will describe the prototypes and the readout electronics, together with the results of the measurements with electron and photon beams with energy up to 20 MeV (Varian Clinac 1800), and the status of the 2D dosimeter development.

Speaker: Giacomo Bartesaghi (INFN Mailand)

Paper bartesaghi.pdf (Protected)

Slides pres_bartesaghi.pdf pres_bartesaghi.ppt

10:15 A time of flight detector for thermal neutrons from radiotherapy Linacs

Boron Neutron Capture Therapy (BNCT) is a therapeutic technique exploiting the release of dose inside the tumour cell after a fission of a 10B nucleus following the capture of a thermal neutron. BNCT could be the treatment for extended tumours (liver, stomach, lung), radio-resistant ones (melanoma) or tumours surrounded by vital organs (brain). The application of BNCT requires a high thermal neutron flux (>5×10 8 n cm−2s−1) with the correct energy spectrum (neutron energy <10 keV), two requirements that for the moment are fulfilled only by nuclear reactors. Several collaborations (among them the INFN PhoNeS project) are trying to produce such a neutron beam with standard radiotherapy Linacs, maximizing with a dedicated photo-neutron converter the neutrons produced by Giant Dipole Resonance by a high energy (>8 MeV) photon beam. In this framework, we have developed a real time detector to measure the thermal neutron time of flight to compute the flux and the energy spectrum. Given the pulsed nature of Linac beams, the detector is a single neutron counting system made of a scintillator detecting the photon emitted after the neutron capture by the hydrogen nuclei. The scintillator signal is sampled by a dedicated FPGA clock thus obtaining the exact arrival time of the neutron itself. The paper will present the detector and its electronics, the feasibility measurements with a Varian Clinac 1800 and the development status of the final 2D dosimeter.

Speaker: Valentina Conti (INFN Mailand)

Paper conti.pdf (Protected)

Slides Pres_Conti.pdf Pres_Conti.ppt

10:40 Coffee break

11:10 Characterisation of Vanilla - a Novel Active Pixel Sensor for Radiation Detection

A monolithic active pixel sensor, Vanilla, with 512x512 pixels (25μm square) has been fully characterised for the first time. Using PTC (Photon Transfer Curve) measurements allowed for the calculation of the read noise, shot noise, full well capacity and camera gain constant. Spectral response measurements detailed the QE of the detector through the UV and visible region. Optimisation of the sensor was made through variation between readout modes (analogue and digital), frame rates, integration times and on-chip biases and voltages. Further comparisons were made with a Vanilla sensor with a thicker epi-layer (20μm, instead of the standard 14μm), to help determine whether or not such sensors are - along with bio-medical and space applications - suitable for use in particle physics experiments.

Speaker: Mr Andrew Blue (Uni Glasgow)

Paper blue.pdf (Protected)

Slides andrewblue1.pdf andrewblue1.ppt

11:35 Response of Micro Pixel Chamber to heavy ions with the energy of several hundred of MeV/n

Astronauts have to receive the risk of radiation exposure in space. The radiation dose rate is about a hundred times as much as that on the ground. Hence, precise radiation dosimetry in space is necessary to control the health of astronauts. We started to develop a new dosimeter named “Position Sensitive Tissue Equivalent Proportional Counter (PS-TEPC)” to measure Linear Energy Transfer (LET) of cosmic-ray precisely. The PS-TEPC consists of the “Micro Pixel Chamber (μ-PIC)” which is one of the micro- pattern gas detectors. We performed the heavy ion irradiation test at HIMAC beam line to evaluate the response of the μ-PIC to the heavy particles. The energy deposit and 3-dimensional tracks of the heavy ions are successfully observed, and the performances were evaluated. We report the result of the performance test of the μ-PIC at HIMAC and the futhre prospect of the PS- TEPC.

Speaker: Tsutomu Nagayoshi (Waseda University, Tokyo)

Paper nagayoshi.pdf (Protected)

Slides vci2007_nagayosi_3.pdf vci2007_nagayosi_3.ppt

12:00 Experimental study of beam hardening artefacts in photon counting breast computed tomography

In the framework of a national project for new imaging techniques for breast cancer diagnosis we are implementing an X-ray Computed Tomography (CT) system, with a design resolution of 1 mm, on the gantry of a dedicated scintillator based single photon emission tomography (SPECT) system for breast Tc-99m imaging, to allow for anatomical co-registration of the radionuclide tomographic slices recorded with the SPECT system. We studied the impact of using a semiconductor based single photon counting detector as detector unit in our X-ray CT system. The detector is a 0.7 mm thick silicon pixel detector (256x256 pixel, 55 micron pitch) bump-bonded to the Medipix2 photon counting readout chip realized by the Medipix2 collaboration. Specifically, we evaluated the beam hardening ”cupping” artefact using homogeneous PMMA cylinders of 12 cm and 14 cm diameter, used as uncompressed breast tissue phantoms, imaged with the 14 mm x 14 mm silicon pixel detector and two X-ray tubes: either a Mo-anode tube or a W-anode tube, operated at 50 kVp, with a 2 mm Al equivalent filtration.

Speaker: Maria Cristina Montesi (INFN Napoli)

Paper montesi.pdf (Protected)

Slides VCI2007_montesi.pdf VCI2007_montesi.ppt

12:25 X-ray Fluorescence and X-ray Transmission Microtomography Imaging System

An X-ray Transmission Microtomography (CT) system combined with an Xray Fluorescence Microtomography (XRFCT) system was implemented in the Brazilian Synchrotron Light Source (LNLS), Campinas, Brazil. The main of this work is to determine the elemental and absorption distribution map in breast tissue samples. The experiments were performed at the X-Ray Fluorescence beamline (D09B-XRF) of the Brazilian Synchrotron Light Source (LNLS), Campinas, Brazil. A quasi-monochromatic beam produced by a multilayer monochromator was used as an incident beam. The fluorescence photons were collected with an energy dispersive HPGe detector (CANBERRA Industries inc.) placed at 90 o to the incident beam, while transmitted photons were detected with a fast Na(Tl) scintillation counter (CYBERSTAR-Oxford anfysik) placed behind the sample on the beam direction. All the tomographic images were reconstructed using a filtered- back projection algorithm.

Speaker: Gabriela Ribeiro Pereira (Nucl. Instrum. Lab., Rio de Janeiro)

Paper pereira.pdf (Protected)

Slides G.Pereira_Vienna.ppt

12:50 X-ray devices for medicine radiography and security

Last years Budker INP has been developing digital scanning low-dose X-ray systems for medical radiography based on ionization chambers. These systems provide dose ∼ 5 μSv for chest inspection (lowest dose in the world). The spatial resolution is 2 p.l./mm, dynamic range is ∼ 1000. About 300 such systems have been produced by industry and are used in Russian hospitals. Similar method was used for express inspection system of passengers with dose below 1 μSv. The resolution is 1 mm, scanning time is below 5 sec. Six such systems are installed in international airports in Russia and successfully operate from beginning of 2005.

Speaker: Yuri Tikhonov (Budker INP)

Slides 9_tikhonov.pdf 9_tikhonov.ppt