966 research outputs found
Development of n-in-p pixel modules for the ATLAS Upgrade at HL-LHC
Thin planar pixel modules are promising candidates to instrument the inner
layers of the new ATLAS pixel detector for HL-LHC, thanks to the reduced
contribution to the material budget and their high charge collection efficiency
after irradiation. 100-200 m thick sensors, interconnected to FE-I4
read-out chips, have been characterized with radioactive sources and beam tests
at the CERN-SPS and DESY. The results of these measurements are reported for
devices before and after irradiation up to a fluence of
n/cm. The charge collection and tracking efficiency of the different
sensor thicknesses are compared. The outlook for future planar pixel sensor
production is discussed, with a focus on sensor design with the pixel pitches
(50x50 and 25x100 m) foreseen for the RD53 Collaboration read-out chip
in 65 nm CMOS technology. An optimization of the biasing structures in the
pixel cells is required to avoid the hit efficiency loss presently observed in
the punch-through region after irradiation. For this purpose the performance of
different layouts have been compared in FE-I4 compatible sensors at various
fluence levels by using beam test data. Highly segmented sensors will represent
a challenge for the tracking in the forward region of the pixel system at
HL-LHC. In order to reproduce the performance of 50x50 m pixels at
high pseudo-rapidity values, FE-I4 compatible planar pixel sensors have been
studied before and after irradiation in beam tests at high incidence angle
(80) with respect to the short pixel direction. Results on cluster
shapes, charge collection and hit efficiency will be shown.Comment: Nuclear Instruments and Methods A, in pres
Optimization of thin n-in-p planar pixel modules for the ATLAS upgrade at HL-LHC
The ATLAS experiment will undergo around the year 2025 a replacement of the
tracker system in view of the high luminosity phase of the LHC (HL-LHC) with a
new 5-layer pixel system. Thin planar pixel sensors are promising candidates to
instrument the innermost region of the new pixel system, thanks to the reduced
contribution to the material budget and their high charge collection efficiency
after irradiation. The sensors of 50-150 m thickness, interconnected to
FE-I4 read-out chips, have been characterized with radioactive sources and beam
tests. In particular active edge sensors have been investigated. The
performance of two different versions of edge designs are compared: the first
with a bias ring, and the second one where only a floating guard ring has been
implemented. The hit efficiency at the edge has also been studied after
irradiation at a fluence of \neqcm. Highly segmented sensors will
represent a challenge for the tracking in the forward region of the pixel
system at HL-LHC. In order to reproduce the performance of 50x50 m
pixels at high pseudo-rapidity values, FE-I4 compatible planar pixel sensors
have been studied before and after irradiation in beam tests at high incidence
angles with respect to the short pixel direction. Results on the hit efficiency
in this configuration are discussed for different sensor thicknesses
Performance of irradiated thin n-in-p planar pixel sensors for the ATLAS Inner Tracker upgrade
The ATLAS collaboration will replace its tracking detector with new all
silicon pixel and strip systems. This will allow to cope with the higher
radiation and occupancy levels expected after the 5-fold increase in the
luminosity of the LHC accelerator complex (HL-LHC). In the new tracking
detector (ITk) pixel modules with increased granularity will implement to
maintain the occupancy with a higher track density. In addition, both sensors
and read-out chips composing the hybrid modules will be produced employing more
radiation hard technologies with respect to the present pixel detector. Due to
their outstanding performance in terms of radiation hardness, thin n-in-p
sensors are promising candidates to instrument a section of the new pixel
system. Recently produced and developed sensors of new designs will be
presented. To test the sensors before interconnection to chips, a punch-through
biasing structure has been implemented. Its design has been optimized to
decrease the possible tracking efficiency losses observed. After irradiation,
they were caused by the punch-through biasing structure. A sensor compatible
with the ATLAS FE-I4 chip with a pixel size of 50x250 m,
subdivided into smaller pixel implants of 30x30 m size was
designed to investigate the performance of the 50x50 m
pixel cells foreseen for the HL-LHC. Results on sensor performance of 50x250
and 50x50 m pixel cells in terms of efficiency, charge
collection and electric field properties are obtained with beam tests and the
Transient Current Technique
Development of a timing chip prototype in 110 nm CMOS technology
We present a readout chip prototype for future pixel detectors with timing
capabilities. The prototype is intended for characterizing 4D pixel arrays with
a pixel size of , where the sensors are Low Gain
Avalanche Diodes (LGADs). The long-term focus is towards a possible replacement
of disks in the extended forward pixel system (TEPX) of the CMS experiment
during the High Luminosity LHC (HL-LHC). The requirements for this ASIC are the
incorporation of a Time to Digital Converter (TDC) within each pixel, low power
consumption, and radiation tolerance up to
to withstand the radiation levels
in the innermost detector modules for of the HL-LHC (in
the TEPX). A prototype has been designed and produced in 110~nm CMOS technology
at LFoundry and UMC with different versions of TDC structures, together with a
front end circuitry to interface with the sensors. The design of the TDC will
be discussed, with the test set-up for the measurements, and the first results
comparing the performance of the different structures
Characterization of timing and spacial resolution of novel TI-LGAD structures before and after irradiation
The characterization of spacial and timing resolution of the novel Trench
Isolated LGAD (TI-LGAD) technology is presented. This technology has been
developed at FBK with the goal of achieving 4D pixels, where an accurate
position resolution is combined in a single device with the precise timing
determination for Minimum Ionizing Particles (MIPs). In the TI-LGAD technology,
the pixelated LGAD pads are separated by physical trenches etched in the
silicon. This technology can reduce the interpixel dead area, mitigating the
fill factor problem. The TI-RD50 production studied in this work is the first
one of pixelated TI-LGADs. The characterization was performed using a scanning
TCT setup with an infrared laser and a Sr source setup
Characterization of passive CMOS sensors with RD53A pixel modules
Both the current upgrades to accelerator-based HEP detectors (e.g. ATLAS, CMS) and also future projects (e.g. CEPC, FCC) feature large-area silicon-based tracking detectors. We are investigating the feasibility of using CMOS foundries to fabricate silicon radiation detectors, both for pixels and for large-area strip sensors. A successful proof of concept would open the market potential of CMOS foundries to the HEP community, which would be most beneficial in terms of availability, throughput and cost. In addition, the availability of multi-layer routing of signals will provide the freedom to optimize the sensor geometry and the performance, with biasing structures implemented in poly-silicon layers and MIM-capacitors allowing for AC coupling. A prototyping production of strip test structures and RD53A compatible pixel sensors was recently completed at LFoundry in a 150nm CMOS process. This presentation will focus on the characterization of pixel modules, studying the performance in terms of charge collection, position resolution and hit efficiency with measurements performed in the laboratory and with beam tests. We will report on the investigation of RD53A modules with 25x100 μm cell geometry
Characterization of passive CMOS sensors with RD53A pixel modules
Both the current upgrades to accelerator-based HEP detectors (e.g. ATLAS, CMS) and also future projects (e.g. CEPC, FCC) feature large-area silicon-based tracking detectors. We are investigating the feasibility of using CMOS foundries to fabricate silicon radiation detectors, both for pixels and for large-area strip sensors. A successful proof of concept would open the market potential of CMOS foundries to the HEP community, which would be most beneficial in terms of availability, throughput and cost. In addition, the availability of multi-layer routing of signals will provide the freedom to optimize the sensor geometry and the performance, with biasing structures implemented in poly-silicon layers and MIM-capacitors allowing for AC coupling. A prototyping production of strip test structures and RD53A compatible pixel sensors was recently completed at LFoundry in a 150nm CMOS process. This presentation will focus on the characterization of pixel modules, studying the performance in terms of charge collection, position resolution and hit efficiency with measurements performed in the laboratory and with beam tests. We will report on the investigation of RD53A modules with 25x100 μm cell geometry
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