Radiation resistant LGAD design Ferrero, M.; Arcidiacono, R.; Barozzi, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2019, Letnik:
919
Journal Article
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In this paper, we report on the radiation resistance of 50-micron thick Low Gain Avalanche Diodes (LGAD) manufactured at the Fondazione Bruno Kessler (FBK) employing different dopings in the gain ...layer. LGADs with a gain layer made of Boron, Boron low-diffusion, Gallium, Carbonated Boron and Carbonated Gallium have been designed and successfully produced at FBK. These sensors have been exposed to neutron fluences up to ϕn∼3⋅1016n∕cm2 and to proton fluences up to ϕp∼9⋅1015p∕cm2 to test their radiation resistance. The experimental results show that Gallium-doped LGAD are more heavily affected by the initial acceptor removal mechanism than those doped with Boron, while the addition of Carbon reduces this effect both for Gallium and Boron doping. The Boron low-diffusion gain layer shows a higher radiation resistance than that of standard Boron implant, indicating a dependence of the initial acceptor removal mechanism upon the implant density.
Highlights • We show that buprenorphine dampens responses to simulated social rejection. • We show that buprenorphine reduces attention to fearful facial expressions, but does not affect attention to ...happy, sad, or angry faces. • We show that buprenorphine selectively increases ratings of positivity for emotional images with social content. • We observed these effects at a relatively low dose of the drug that does not produce significant euphoria.
Radiation hardness of thin Low Gain Avalanche Detectors Kramberger, G.; Carulla, M.; Cavallaro, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2018, Letnik:
891
Journal Article
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Low Gain Avalanche Detectors (LGAD) are based on a n++-p+-p-p++ structure where an appropriate doping of the multiplication layer (p+) leads to high enough electric fields for impact ionization. Gain ...factors of few tens in charge significantly improve the resolution of timing measurements, particularly for thin detectors, where the timing performance was shown to be limited by Landau fluctuations. The main obstacle for their operation is the decrease of gain with irradiation, attributed to effective acceptor removal in the gain layer. Sets of thin sensors were produced by two different producers on different substrates, with different gain layer doping profiles and thicknesses (45, 50 and 80 μm). Their performance in terms of gain/collected charge and leakage current was compared before and after irradiation with neutrons and pions up to the equivalent fluences of 5⋅1015 cm−2. Transient Current Technique and charge collection measurements with LHC speed electronics were employed to characterize the detectors. The thin LGAD sensors were shown to perform much better than sensors of standard thickness (∼300 μm) and offer larger charge collection with respect to detectors without gain layer for fluences <2⋅1015 cm−2. Larger initial gain prolongs the beneficial performance of LGADs. Pions were found to be more damaging than neutrons at the same equivalent fluence, while no significant difference was found between different producers. At very high fluences and bias voltages the gain appears due to deep acceptors in the bulk, hence also in thin standard detectors.
Ultra-fast silicon detectors Sadrozinski, H. F.-W.; Ely, S.; Fadeyev, V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2013, Letnik:
730
Journal Article
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We propose to develop a fast, thin silicon sensor with gain capable to concurrently measure with high precision the space (∼10μm) and time (∼10ps) coordinates of a particle. This will open up new ...application of silicon detector systems in many fields. Our analysis of detector properties indicates that it is possible to improve the timing characteristics of silicon-based tracking sensors, which already have sufficient position resolution, to achieve four-dimensional high-precision measurements. The basic sensor characteristics and the expected performance are listed, the wide field of applications are mentioned and the required R&D topics are discussed.
•We are proposing thin pixel silicon sensors with 10's of picoseconds time resolution.•Fast charge collection is coupled with internal charge multiplication.•The truly 4-D sensors will revolutionize imaging and particle counting in many applications.
Low Gain Avalanche Diodes (LGADs) are thin (20-50
μm
) silicon diode sensors with modest internal gain (typically 5 to 50) and exceptional time resolution (17
ps
to 50
ps
). However, the granularity ...of such devices is limited to the millimeter scale due to the need to include protection structures at the boundaries of the readout pads to avoid premature breakdown due to large local electric fields. Here, we present a new approach – the Deep-Junction LGAD (DJ-LGAD) – that decouples the high-field gain region from the readout plane. This approach is expected to improve the achievable LGAD granularity to the tens-of-micron scale while maintaining direct charge collection on the segmented electrodes.
Experimental Study of Acceptor Removal in UFSD Jin, Y.; Ren, H.; Christie, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2020, Letnik:
983, Številka:
C
Journal Article
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The performance of the Ultra-Fast Silicon Detectors (UFSD) after irradiation with neutrons and protons is compromised by the removal of acceptors in the thin layer below the junction responsible for ...the gain. This effect is tested both with capacitance–voltage, C–V, measurements of the doping concentration and with measurements of charge collection, CC, using charged particles. We find a perfect linear correlation between the bias voltage to deplete the gain layer determined with C–V and the bias voltage to collect a defined charge, measured with charge collection. An example for the usefulness of this correlation is presented.
We previously reported that an abnormal CSF opening pressure (OP) in children was greater than 28 cm H(2)O. Since elevated intracranial pressure can cause optic nerve head edema (ONHE), we would ...expect that most patients with ONHE would have an OP greater than 28 cm H(2)O. This study describes the range of OP for children with ONHE and compared them to age-matched controls without ONHE.
Case subjects were children (1-18 years of age) enrolled in a prospective study of CSF OP that demonstrated ONHE at time of lumbar puncture and that the ONHE later resolved. Patients with ONHE secondary to infectious, inflammatory, or ischemic conditions were excluded. Control subjects from the same study, but without ONHE, were matched to cases.
Of the 472 subjects enrolled in the study, 41 OP measurements were obtained from 33 patients with ONHE who did not have any exclusionary criteria and matched to 41 control subjects without ONHE. Case subjects had a significantly higher OP (mean, 41.4 cm H(2)0; range, 22-56) than control subjects (mean, 18.9 cm H(2)O; range, 9-29; p < 0.01). Forty of 41 (97.6%) case subjects and 2 of 41 (4.8%) control subjects had OP measures >28 cm H(2)O.
Children with ONHE not related to infectious, inflammatory, or ischemic causes typically have an OP >28 cm H(2)O, significantly higher than age-matched controls without ONHE. This study provides further support to our previously published findings that suggests an abnormal OP in children is typically above 28 cm H(2)O.
Sensors for ultra-fast silicon detectors Sadrozinski, H.F.-W.; Baselga, M.; Ely, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2014, Letnik:
765
Journal Article
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We report on electrical and charge collection tests of silicon sensors with internal gain as part of our development of ultra-fast silicon detectors. Using C–V and α TCT measurements, we investigate ...the non-uniform doping profile of so-called low-gain avalanche detectors (LGAD). These are n-on-p pad sensors with charge multiplication due to the presence of a thin, low-resistivity diffusion layer below the junction, obtained with a highly doped implant. We compare the bias dependence of the pulse shapes of traditional sensors and of LGAD sensors with different dopant density of the diffusion layer, and extract the internal gain.
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