13th RD50 Workshop

10 Nov 2008, 13:30 → 12 Nov 2008, 16:00 Europe/Zurich

40-S2-D01 (CERN)

Michael Moll (CERN)

13th RD50 Workshop on Radiation hard semiconductor devices for very high luminosity colliders

Monday, 10 November

Welcome

1 Introduction

Speakers: Mara Bruzzi (INFN and University of Florence), Michael Moll (CERN)

Slides 081110-Intro-Michael-Moll.pdf 081110-Intro-Michael-Moll.ppt

Defect and Material Characterization

2 Radiation induced point- and cluster-related defects with strong impact to damage properties of silicon detectors

I. Pintilie (a), _E. Fretwurst_ (b), A. Junkes (b), G. Lindstroem (b) /(a)/ /National Institute of Materials Physics, Bucharest, Romania (b) Institute for Experimental Physics, University of Hamburg, Germany This work is focusing on the investigation of those radiation induced defects causing degradation effects of Silicon detector performance. Comparative studies of the defects induced by irradiation with Co^60 - γ rays, 23 GeV protons and 1 MeV equivalent reactor neutrons revealed the existence of some point defects and cluster related centers having a strong impact to damage properties of Si diodes. The detailed relation between the “microscopic” reasons as based on defect analysis and their “macroscopic” consequences for detector performance are presented and discussed.

Speaker: Eckhart Fretwurst (University of Hamburg)

Slides NSS_Ioana_Pintilie_N15_1_RD50.pdf NSS_Ioana_Pintilie_N15_1_RD50.ppt

3 Anneal dependent variations of lifetime and deep levels in neutron irradiated MCZ Si

The photoconductivity spectra (PC) and lifetime measurement were used for control of transforms and competition of recombination and generation centres in neutron irradiated MCZ Si. In the as-irradiated material the recombination centres prevail and cause mono-exponential decay with nearly linear decrease of carrier lifetime from several microseconds to sub-nanoseconds with enhancement of fluence from 1012 to 31016 n/cm2. Isochronal 24 hours anneals in the range of temperatures from 80 to 420 C induce variation of the density of different deep levels, which depends on irradiation fluence. Appearance of two-exponential decays and the changes of the effective lifetimes of the initial and asymptotic decays imply the complicated transformations of radiation defects under heat treatments. Qualitatively these transforms can be understood when existence and dominance of cluster defects is assumed. The PC spectra allowed to identity the deep levels playing role in free carrie capture and generation.

Speaker: Prof. Juozas Vaitkus (Vilnius University)

Slides Photoconductivity[2]_JV.pdf Photoconductivity[2]_JV.ppt

4 Recent results on bistable cluster related defects

It was previously shown*, that the bistable cluster defect levels E4a** and E4b** anneal out at the same temperature like the divacancy in neutron and proton irradiated oxygen rich material (MCz and oxygen enriched Epi). Defect concentrations were obtained by means of Deep Level Transient Spectroscopy (DLTS) and Thermally Stimulated Current technique (TSC). In addition oxygen lean Epi and FZ material was investigated in the same way, in order to exclude an impurity dependence of those defects. First results of our study support the former observation. Furthermore, we observe that the DLTS and TSC signals of point defects, like the vacancy-oxygen complex and the divacancy, are strongly influenced by the presence of disordered regions (clusters). * Work presented at the RADECS08 and RESMDD08 conference ** M. Moll et al., Nucl. Instr. & Meth. in Phys.Res. B 186 (2002) 100-110, also known as E4 and E5

Speaker: Alexandra Junkes (Hamburg University)

Slides RD50_junkes.pdf

5 Characterisation of defect centres in epitaxial silicon irradiated with high proton fluences

Systematic studies of defect centres in epitaxial silicon irradiated with high fluences of 24 GeV/c protons, ranging from 1.6e15 to 1.6e16 cm^-2, have been performed using High-Resolution Photoinduced Transient Spectroscopy (HRPITS). The studies were correlated with the measurements of the leakage current of the epitaxial detectors and the estimations of the electron mobility and lifetime product. The comparison of the defect structure of the oxygenated and standard n-type epitaxial layers is shown.

Speaker: Pawel Kaminski (Institute of Electronic Materials Technology)

Slides 13th_Workshop_Si_Epi_PITS_Final.pdf 13th_Workshop_Si_Epi_PITS_Final.ppt

15:15 Coffee break

6 Discussion Session: Defect and Material Characterization

Minutes Discussion_on_Defect_and_Material_Characterization.docx Discussion_on_Defect_and_Material_Characterization.pdf

New developments and Non-LHC applications

7 Infrared transparent detectors

In large systems, as ATLAS, the detectors are aligned using mechanical systems and laser beams. Another option, implemented in CMS, is to use the signal generated by the laser beam in the detector to measure its position. Unfortunately, standard detectors present a high light absorption, and therefore it is almost impossible to generate signal in many detector layers using one single laser beam. In collaboration with Institute of Physics in Cantabria, Spain (IFCA) we are developing detectors optimized to present infrared transmission coefficient over 50%, in this way it will possible to detect signal in 5 detectors simultaneously.

Speaker: Prof. Manuel Lozano Fantoba (CNM Instituto de Microelectronica de Barcelona)

Slides RD50_CERN_08-11_Lozano.pdf RD50_CERN_08-11_Lozano.ppt

8 Radiation damage of video device in a fusion stellarator

The EDICAM (Event Detection Intelligent Camera) will be used for video diagnostic in the Endelstein 7X. The camera consists of three modules, the Sensor Module (SM) the Image Processing and Control Unit module and the Image Readout Card module. The sensor module of the camera will be located at the plasma facing end of the selected tangential ports. Because of this the SM should operate in harsh environment under neutron and gamma radiation. The gamma and neutron radiation levels and spectrums were calculated by MCNP code. The calculated neutron fluence 3.5•10^13 n/cm^2 (16.7Gy in Si target) for one year operation. The neutron spektrum is rather hard, half of it consists of fast neutrons (2.45MeV) the other half epithermal energy neutrons (0.2 eV-1 MeV). The neutron irradiation was carried out in the BIO testing site of Budapest Neutron Centre where we had good gamma shielding, which allowed to reach the desired yearly neutron fluence and spectrum estimated by MCNP at low gamma background. The SM’s dark current was in the centre of interest. Statistical methods were used for the evaluation of the dark current’s behavior with different camera exposure times. The measurement showed that SM endures the estimated neutron dose although it will lose a big fraction of it’s dynamics.

Speaker: Gabor Nafradi (BUTE-INT)

Slides Radiation_damage_of_video_device_in_a_fusion.pdf Radiation_damage_of_video_device_in_a_fusion.ppt

Collaboration Board Meeting

Tuesday, 11 November

Pad Detector Characterization and Defect Engineering

9 Annealing studies of mixed irradiated MICRON diodes

A set of MICRON diodes was irradiated with different fluences of protons and pions up to 1.1e15 p/cm2 followed by additional 2e14 n/cm2. The compensation of the stable damage due to neutron and charged hadron irradiation was observed for the MCz-n samples, while for FZ detectors the damage scales with equivalent fluence. The diodes were annealed up to 10000 min at 60C in steps, during which CV-IV and CCE measurements were performed.

Speaker: Gregor Kramberger (Jozef Stefan Institute)

Slides Kramberger_Mixed_Annealing.pdf Kramberger_Mixed_Annealing.ppt

10 TCT measurements on MCz

TCT measurements on a series of proton and neutron irradiated MCz p- and n-type detectors.

Speaker: Katharina Kaska (CERN)

Slides updated slides

11 Charge collection and trapping effects in 75 μm, 100 μm and 150 μm thick n-type epitaxial silicon diodes after proton irradiation

Epitaxial silicon pad diodes of 75 μm, 100 μm and 150 μm thickness and both ST and DO n-type material have been investigated after 24 GeV/c proton irradiation (CERN PS) in an equivalent fluence range between 1e14 n/cm² and 1e16 n/cm². A new TCT setup with 670 nm laser light enabled the measurement of time-resolved electron current pulse shapes in 150 μm thick diodes. Thus the charge correction method could be used in order to extract the trapping time constant. Moreover CCE measurements with 5.8 MeV alpha-particles will be presented and compared to simulation.

Speaker: Jörn Lange (Hamburg University)

Slides RD50_Nov08_Joern_Lange.pdf RD50_Nov08_Joern_Lange.ppt

12 Discussion: Pad Detector Characterization and Defect Engineering

10:30 Coffee Break

Full Detector Systems

13 X-Ray irradiation on p-type micro-strip detectors with p-spray and moderated p-spray isolations

Two micro-strip sensors were irradiated with X-ray irradiation facility in Karlsruhe to investigate the change of the inter-strip resistance and capacitance as a function of the recieved dose. For one of the structures a p-spray isolation was chosen, for the other one a moderated p-spray.

Speaker: Michael Beimforde (Werner-Heisenberg-Institut - Max-Planck-Institut fuer Physik)

Slides Beimforde13thRD50.pdf

14 Questions about extrapolation at SLHC doses of silicon parameter measured after lower fluences

Discussion of VFD, trapping and reverse currrent

Speaker: Gianluigi Casse (University of Liverpool)

Slides Casse.pdf Casse.ppt

15 Measurements of CCE/IV/annealing behaviour of microstrip detectors irradiated with reactor neutrons and protons to SLHC doses

Measurements of micro-strip sensors made with the RD50 mask sets with various silicon substrates (n-type/p-type FZ/MCz/EPI) have been compared after high doses of neutron and protons comparable to those expected at the SLHC. Issues of charge collection, sensor power, and annealing performance will be evaluated for both standard (~300 um) and thin (140-200 um) detectors.

Speaker: Dr Anthony Affolder (University of Liverpool)

Slides affolder-rd50.pdf affolder-rd50.ppt

16 Test beam results of heavily irradiated magnetic Czochralski silicon (MCz-Si) strip detectors

N-type MCz-Si strip detectors with an area of 16 cm^2 were irradiated to several different fluences up to 3x10^15 1 MeV neq/cm^2 with protons or with neutrons and protons depending on the detector. The beam test was carried out at CERN H2 area using a reference beam telescope and an efficient cooling system.

Speaker: Panja-Riina Luukka (Helsinki Institute of Physics HIP)

Slides P_Luukka_presentation.pdf P_Luukka_presentation.ppt

12:20 Lunch

17 Status of the ALIBAVA readout system

A readout system for microstrip silicon sensors has been developed as a result of a collaboration among the University of Liverpool, the CNM of Barcelona and the IFIC of Valencia. The name of this collaboration is ALIBAVA and it is integrated in the RD50 Collaboration. This system is able to measure the collected charge in one or two microstrip silicon sensors by reading out all the channels of the sensor(s), up to 256, as an analogue measurement. The system uses two Beetle chips to read out the detector(s) . The Beetle chip is an analogue pipelined readout chip used in the LHCb experiment. The system can operate either with non-irradiated and irradiated sensors as well as with n-type and p-type microstrip silicon sensors. Heavily irradiated sensors will be used at the SLHC, so this system can be used to research the performance of microstrip silicon sensors in conditions as similar as possible to the SLHC operating conditions. The system has two main parts: a hardware part and a software part. The hardware part acquires the sensor signals either from external trigger inputs, in case of a radioactive source setup is used, or from a synchronised trigger output generated by the system, if a laser setup is used. This acquired data is sent by USB to be stored in a PC for a further processing. The hardware is a dual board based system. The daughterboard is a small board intended for containing two Beetle readout chips as well as fan-ins and detector support to interface the sensors. The motherboard is intended to process the data, to control the whole hardware and to communicate with the software by USB. The software controls the system and processes the data acquired from the sensors in order to store it in an adequate format file. The main characteristics of the system will be summarized. Results of measurements acquired with n-type and p-type non-irradiated and irradiated detectors, using both the laser and the radioactive source setup, will be also presented and discussed. Finally, the production status of the system will be presented.

Speaker: Mr Ricardo Marco (IFIC-Instituto de Física Corpuscular)

Slides rd50_13th_talk.pdf rd50_13th_talk.ppt

18 Pixel Sensor Measurements at CERN

Speaker: Heinz Pernegger (CERN)

Slides PixelDet_Pernegger.pdf

19 Signal height in irradiated Silicon Pixel Detectors

In order to establish a fluence limit for the radiation hardness of the CMS barrel pixel detector and for conventional n-on-n sensors in general, pixel sensors of the size of one CMS pixel readout (PSI46V2.1) have been bumpbonded and irradiated with positive pions up to 6E14 Neq/cm2 and with protons up to 4E15 Neq/cm2. The sensors were taken from production wafers of the CMS barrel pixel detector. They use n-type DOFZ material with a resistance of about 3.7 k Ohm cm and an n-side read out. As the performance of silicon sensors is limited by trapping, the response to a Sr-90 source was investigated. The highly energetic beta-particles represent an approximation to minimum ionizing particles. The bias dependence of the signal for a wide range of fluences will be presented.

Speaker: Jhon Acosta (Univ. of Puerto Rico - Mayaguez)

Slides Jhon_Acosta.pdf

20 Production of n-in-n and n-in-p pixels on Fz and MCz silicon with CiS

We present a production of n-in-n and n-in-p planar pixel sensors on Fz and MCz silicon that we intend to perform with CiS. We aim to investigate the performances of these detectors at SLHC fluences comparing different bulk materials and to study the feasibility of operating planar pixel sensors with slimmed or active edges.

Speaker: Anna Macchiolo (Max-Planck-Institut fur Physik)

Slides CIS_SUBMISSION_2.pdf CIS_SUBMISSION_2.ppt

21 Discussion: Full Detector Systems

Status 6 inch 6inch_Micron.pdf

15:30 Coffee break

3D detectors & other new detector structures

22 Progress in R & D on silicon edgeless strip detectors with Current Terminating Structure

The overview on silicon edgeless strip detectors developed for close-to-beam experiments at CERN will be presented. The recent progress of these detectors is related to the elaboration of the specific design - edgeless detectors with current terminating structure that was successfully realized in p-on-n Si edgeless detectors for the TOTEM experiment. The potential and electric field distributions at the detector sensitive diced edge which control the detector operation are simulated and studied experimentally using two methods – MicroProbe Technique and Scanning Transient Current Technique. The model of edgeless detector operation is developed and applied for predictions on radiation hardness of edgeless detectors.

Speaker: Elena Verbitskaya (A.F. Ioffe Physical Technical Inst.)

Slides Verbitskaya__RD50_13_wksh.pdf Verbitskaya__RD50_13_wksh.ppt

23 New fabrication of 3D detectors, np and pn devices

I will report on the fabrication of new 3D detectors and the future plan for bump bonding Atlas pixels and Medipix2 chips.

Speaker: Dr Giulio Pellegrini (Centro Nacional de Microelectronica CNM-IMB-CSIC)

Slides Pellegrini_RD50_Nov08.pdf Pellegrini_RD50_Nov08.ppt

24 3D stc Strip Detector Test Beam Results

A 3D stc micro strip detector was placed in a beam of 180GeV pions at CERN in 2007. The detector was connected to analogue read-out electronics as used in the tracking system of the LHCb experiment. We present the results from the analyis of the test beam data, including signal/noise ratio measurements and efficiciency studies. This work has been done in close collaboration with Trento (FBK-irst and INFN/UNITN) and Glasgow.

Speaker: Ulrich Parzefall (Fakultaet fuer Physik)

Slides Testbeam07_v6.pdf Testbeam07_v6.ppt

25 Analysis of the 2008 Testbeam with 3D ddtc Detectors (Status Report)

In July 2008, a testbeam with double-sided double type column (ddtc) 3D detectors was performed at the CERN SPS. It was provided by the Helsinki group in the framework of CMS. This talk presents the testbeam setup and a detector under test, produced by FBK-irst. The current status of the analysis, which is done in collaboration with the groups from Glasgow and Helsinki, and first (preliminary) results will be shown.

Speaker: Michael Koehler (Universitaet Freiburg)

Slides 3Dddtc_Koehler.pdf

26 Predictions for 3D detector operation in SuperLHC environment

The different constructions of silicon 3D detectors are analyzed and tabulated in terms of combinations of two simple elements: the p-n junction and the ohmic columns. In the p-n junction column two parts are recognized: a cylindrical one which radius increases with the bias, and a semi-spherical “dead” tip with a maximal electric field due to the focusing effect. This consideration allows analytical extrapolation of the detector critical parameters to its operation in the upgraded LHC facility.

Speaker: Vladimir Eremin (Ioffe Physical Technical Institute RAS)

Slides Eremin_RD50_13_wksh_presented_3D_detectors.pdf Eremin_RD50_13_wksh_presented_3D_detectors.ppt

27 Discussion on 3D detectors

Workshop Dinner

Café, Restaurant des Transports

Ayer Graziella
boulevard James-Fazy 6
1201 Genève

Téléphone 022 732 69 16

28 Dinner

# Public Bus Leaving CERN Bus stop at 19:21 sharp!! Restaurant Home Page Apéro : Kir Entrée : Terrine aux poivres verts garnie Plat : Médaillon de chevreuil, garniture de chasse Dessert : Glaces/Sorbets Café Boissons : 1 bouteille Pinot Noir « Les Faunes » pour trois personnes, Bouteilles d’eau.

Wednesday, 12 November

Discussion: Statusreport 2008 - Workplan 2009

• Preparation of the statusreport 2008 presentation (LHCC - 19.November)
• Workplan for 2009

29 Discussions

10:30 Coffee break

RD50 - WODEAN - Meeting

Discussions on Defect studies and in particular on the WODEAN publication