During the era of the High-Luminosity (HL) LHC the experimental devices will be subjected to enhanced radiation levels with fluxes of neutrons and charged hadrons in the inner detectors up to $~2.3×10^{16}$ $n_{eq}/cm^2$ and total ionization doses up to ~1.2 Grad. A systematic program of radiation tests with neutrons and charged hadrons is being run by the LHC detector collaborations in view...
A proton irradiation site for silicon detectors has been developed at Bonn University. The site is located at the Bonn Isochronous Cyclotron of Helmholtz Institut für Strahlen- und Kernphysik (HISKP) which provides protons with 14 MeV ($\approx$ 12 MeV on-device) kinetic energy. Light ions, such as deuterons, alphas up to $^{12}$C, can also be produced with kinetic energies from 7 to 14 MeV...
Currently CNM-Barcelona is involved in two projects that focus on the development of innovative planar and 3D SiC sensors for harsh environment applications. Both projects are in alignment with the objectives put forward in the RD50 Research Project 2018, specifically targeting two milestones from the New Materials research line: the fabrication of new radiation detectors in different wide...
The work is dedicated to studying the kinetics of the process of charge collection in silicon detectors at a temperature of 1.9 K in situ irradiated by protons. The main research method is TCT, which allows one to receive current responses of high time resolution. As a result of in situ tests, non-standard current pulse shapes were obtained, which can be described only within the framework of...
The study is concerned with enhanced influence of defect clusters on the profiles of the electric field E and effective space charge concentration Neff in Si detectors irradiated with 1.62 GeV 40Ar ions and operating at temperatures from 292 down to 200 K. The electric field profiles reconstructed from the shapes of the detector current pulse response measured by TCT demonstrated the...
In this research the low energy neutron diffraction technique, a non-destructive technique, was applied to analyze hadron generated clusters. The Si single crystals were irradiated in TRIGA nuclear reactor to the neutron fluence 1e16 cm-2.
The experiment was performed on IN3 beam at ILL (www.ill.fr). Instrument was used in fully elastic mode, with incident and scattered wave vectors of...
The electron transport via defect network becomes important in highy irradiated solid state and in Si clusters of defects induced by hadron irradiation if it acts as a dipole type recombination center.
Electron transport via localized defect sites can be roughly described by Fermi Golden Rule type hopping. However, this approach does not include electron delocalization among nearby defect...
A short introduction to the measurement method low temperature photoluminescence (LTPL) spectroscopy is given. Samples from a low gain avalanche detector processing run are studied by LTPL before and after electron irradiation. In carbon doped samples the characteristic G-line is found after electron irradiation.
The presented report is focused on the problem of analyzing irradiation-induced highly disordered regions in the detector bulk. Such regions could be settled down close to the Bragg Peak maximum - ion stopping range. Noted regions were created in the detectors of low-resistance silicon via low energy irradiation by heavy 40Ar ions at the Ioffe Institute Cyclotron. Electrophysical properties of...
Defect investigation studies, by TSC and TEM techniques, after neutron irradiation of high resistivity PiN and LGAD float-zone silicon diodes have been performed. The diodes were irradiated with fluences of E14 and E15 n/cm2. TSC studies during annealing treatments at 80C have been performed with emphasis on the acceptor-removal process. The results are discussed in correlation with the...
The admittance of n+p pad diodes (200 μm thickness, 5×5 mm$^2$ area) irradiated by 24 GeV/c protons to 1 MeV neutron equivalent fluences Φ$_{eq}$ = 3, 6, 8 and 13×10$^{15}$ cm$^{-2}$ has been measured for reverse voltages Vrev between 1 and 1000 V and for frequencies f between 100 Hz and 2 MHz at temperatures T = –30 °C and –20 °C. A simple model, which assumes that radiation damage causes a...
This project investigates radiation damage of epitaxial P type silicon.
Test structures consisting of Schottky diodes and pn junctions of different size and flavors are going to be fabricated at different facilities, including RAL and Carleton.
The structures are fabricated on a 50 um thick epitaxial layer of various P type doping: 1e13, 1e14, 1e15, 1e16, and 1e17 cm-3.
Up to 25...
The latest development of LGAD sensors by IHEP-NDL in China have been evaluated with laser , beta source and test beam. The result of proton irradiation at CIAE will be introduced. The simulation of LGAD based on TRACS and TCAD study with irradiation modeling will also be shown.
The new 6" CNM SoI LGADs are studied under neutron irradiation on fluences up to 5e15 neq/cm2. Gain reduction, dark rate, leakage current and breakdown voltage is estimated for two different doping concentrations of the gain layer. Through charged particle measurements, the time resolution and gain is estimated for sleeted fluneces in three different temperatures (-10C, -20C and -30C).
Several sets of LGADs produced by HPK and CNM withing the framework of ATLAS high granularity timing detectors were irradiated with reactor neutrons up to fluences of 6e15 cm-2. After the irradiation they underwent controlled annealing at 60C. At each annealing step the sensors were measured with Sr90 electrons at -30C in timing setup. The evolution of signal and time resolution at different...
Low-Gain Avalanche Diodes (LGADs) exhibit excellent timing performance, in the orders of a few tens of ps, thanks to a combination of high signal-to-noise ratio and short rise time. This technology has attracted interest for applications in a wide variety of fields such as in timing detectors for High-Energy Physics experiments or for the detection of neutrons with precise timing, among...
In this contribution we present recent results on the characterization of Resistive AC-Coupled Silicon Detectors (RSD) produced by FBK in 2019. Both electrical measurements and signal response of un-irradiated sensors will be presented. Being the RSD devices intended for 4D particle tracking, we also show preliminary but very promising results about their spatial and time resolution. All the...
In this contribution, we will present the latest results from laboratory measurements on UFSD3.1 production form FBK. Focus of the production is to investigate different strategies to design inter-pad on LGAD sensors, to reduce at minimum the size of the no-gain region between pads, while maintaining stable operation of the detectors.
Trench-Isolated LGAD (TI-LGAD) is a novel LGAD design where the standard inter-pixel isolating structure has been replaced with a trench, physically etched in the silicon and filled with a dielectric material.
The first TI-LGAD samples with 250 µm pitch have been produced at FBK and characterized with I-Vs and C-Vs analysis. In this contribution, we will discuss the technology design and the...
Trench-Isolated Low-Gain Avalanche Diodes (TI-LGAD) are a recent development of LGAD, in which the standard isolation structures are replaced by narrow trenches that are etched in the Silicon substrate. Trenches allow reducing the inactive region between pixels from the 30-40 microns of the standard technology down to a few microns, significantly improving the fill factor of TI-LGADs with...
The maximum operating voltage, efficiency and stability of 1x1 mm highly proton and neutron irradiated LGADs is presented for a boron, boron+carbon and gallium gain layer. Through charged particle measurements, electrical characterization and risk analysis using experience on calamities, a discussion is introduced on establishing safe operating limitations on thin LGADs.
In this contribution, I will review our current understanding of the working points of UFSDs manufactured by HPK and FBK during the lifetime of the CMS and ATLAS timing layer detectors.
Specifically, I will point out the achievable time resolution as a function of fluence, including the effect of the leakage current Shot noise.
This talk presents updated measurements of fluence-sensitive radiation damage quantities with the ATLAS pixel detector. In particular, the first full Run 2 fluence measurement using the leakage current is presented. The mismodeled |z|-dependence is observed across all of Run 2 and with measurements of additional quantities. In addition to leakage current, the depletion voltage is also...
This contribution will present the status and latest results of the CMOS work package within the CERN-RD50 collaboration. This will consist of describing the RD50 Data AcQuisition System (DAQ) for the test chip RD50-MPW1 and the obtained results, including chip hit maps and pixel address decoding debugging. Measurements of the effects of the clock rate of the on-chip state machine on the...
We present a general concept to improve the spatial resolution of silicon pixel detectors via introducing position dependent inter-pixel cross-talk. By segmenting the readout implantations and AC-coupling the resulting sub-pixels, a part of the pixel charge is shared with neighboring pixels. Simulations to study the impact of different coupling capacitor values on spatial resolution are...
The Transient Current Technique (TCT) has been evolved as one of the principal tools for studying solid state particle detectors over the years. Si detectors are being exposed to intense radiation environment in collider experiments which affects their charge collection performance. The strength of the signal produces because of generation of charge carriers by traversing particles, gets...
The Transient Current Technique (TCT) is a very important technique for characterization of unirradiated and irradiated silicon detectors.
In recent years a novel method, the Two Photon Absorption - Transient Current Technique (TPA-TCT), based on the charge carrier generation by absorption of two photons, was developed. TPA-TCT proved to be very useful in 3D characterization of silicon...
TCT-TPA (Transient Current Technique-Two Photon Absorption) is a new pulsed infrared laser method for mapping the electric field in solid state particle detectors, combining high spatial resolution with the use of Ramo theorem. As it uses focused ultrashort infrared lasers, plasma effects need to be contended with. They are responsible of the increase of detector current pulse duration. From a...
In this contribution measurements with detectors irradiated with reactor neutrons up to 1e17 n/cm2 will be presented. Measurements were made with CNM LGAD pad detectors made on 75 um thick epitaxial layer on low resistivity support silicon. LGADs were chosen because this was the available set of thin pad detectors that could withstand high bias voltages. Edge-TCT, charge collection with Sr-90...
During studies on the signal formation in silicon strip sensors, irradiated and annealed until the occurring of the phenomena of charge multiplication, it was observed that previously flowing free carriers changed the detector response. In particular, it was inferred that trapping of free carriers produced by a laser pulse changes the electric field distribution.
The impact of subsequent...
A method is presented which allows to obtain the position-dependent electric field and charge density by fits to velocity profiles from edge-TCT data from silicon strip-detectors. The validity and the limitations of the method are investigated by simulations of non-irradiated n+p pad sensors and by the analysis of edge-TCT data from non-irradiated n+p strip-detectors. The method is then used...
In this talk we present for the first time, the 3D pixel sensors irradiated with neutrons up to a fluence of 3$\times$10$^{17}$ [n$_{eq}$ /cm$^2$]. TCT measurements and charge collection efficiency showed that the sensors remain operative despite the unprecedented levels of irradiation similar of those estimated in the Future Circular Collider (FCC).
