Abstract
For operation at the High Luminosity Large Hadron Collider
(LHC), the ATLAS experiment is building a new all-silicon inner
tracker (ITk). The production and testing of thousands of silicon
...pixel and strip modules is required to cover the estimated
180 m
2
of the total surface area. A compact, affordable and
robust module characterization system is required for in-situ
testing prior any test beam campaign or installation. A test bench
setup based on an infrared laser was developed at IJCLab, allowing
also for the use of micro-metric precision scanning with a
radioactive source. A detailed schema of the setup, operating
principles and testing methods are described in this paper, together
with the first results obtained with a FE-I4 silicon pixel module.
The proven potential of 3D geometries at higher than 1016n˙eq/cm2 radiation fluences, in combination with a small cell approach, makes them an excellent choice for a combined precision timing ...tracker. In this study, the preliminary results on timing resolution of a single 50×50μm2 3D pixel cell are presented through charge collection measurements with discrete electronics in a laboratory setup. Additionally, in a test-beam campaign with 160 GeV SPS pions, a detailed timing, field and efficiency map is presented using a multi-plane timing telescope with an integrated pixelated matrix. Finally, another testbeam campaign has been completed with the help of the EUDET telescope, to study field uniformity, Landau contribution, collected charge and incidence angles of +/−12°; with a preliminary 5μm spatial resolution through MIMOSA CMOS tracking at CERN SPS pion beams.
•Sensors for vertex detectors in high energy physics with high luminosity scenarios.•Testbeam setup development for time and spatial resolution measurements.•3D silicon Pixel sensor time resolution results.
Towards radiation tolerant sensors for pico-second timing, several dopants are explored. Using a common mask, CNM produced LGADs with boron, boron + carbon and gallium gain layers are studied, under ...neutron and proton irradiation. With fluences ranging from
10
14
to
6 × 10
15
n
eq
/cm
2
on both particle species, results focus on acceptor removal, gain reduction via electrical characterization, timing performance and charge collection. An emphasis is placed on stability via dark rate and operating voltage studies.
Abstract
The spatial and temporal performance of a four-plane system
composed of silicon sensors bump-bonded to Timepix4 ASICs is
assessed with a 180 GeV/c mixed hadron beam at the CERN SPS and
...reported in detail. Particle tracks are reconstructed using
time-space measurements from the four detector planes, two
100 μm planes perpendicular to the beam and two 300 μm
sensors under an angle of 9°. The spatial hit resolution
is assessed to be (15.5 ± 0.5) μm and (4.5 ± 0.3) μm
for 100 μm and 300 μm thick sensors, respectively.
The timestamps from the detectors are also measured with fine
precision, yielding time resolutions of (452 ± 10) ps,
(420 ± 10) ps, (639 ± 10) ps, (631 ± 10) ps for the two
100 μm and two 300 μm thick sensors respectively.
These measurements are combined to a track time resolution of
(340 ± 5) ps. The design of the detector system is described
together with its data acquisition system, operational
infrastructure, and dedicated software.
Abstract
Low Gain Avalanche Detectors (LGADs) are n-on-p silicon sensors with an extra p-layer below the collection electrode which provides signal amplification. When the primary electrons reach the ...amplification region new electron-hole pairs are created that enhance the generated signal. The moderate gain of these sensors, together with the relatively thin active region, provide precise time information for minimum ionizing particles. To mitigate the effect of pile-up at the HL-LHC the ATLAS and CMS experiments have chosen the LGAD technology for the High Granularity Timing Detector (HGTD) and for the End-Cap Timing Layer (ETL), respectively. A full characterization of recent productions of LGAD sensors fabricated at CNM has been carried out before and after neutron irradiation up to 2.5 × 10
15
n
eq
/cm
2
. Boron-doped sensors produced in epitaxial and Si-on-Si wafers have been studied. The results include their electrically characterization (IV and bias voltage stability) and performance studies (charge and time resolution) for single pad devices with a Sr-90 radioactive source set-up. The behaviour of the Inter-Pad region for irradiated 2 × 2 LGAD arrays, using the Transient Current Technique (TCT), is shown. The results indicate that the Si-on-Si devices with higher resistivity perform better than the epitaxial ones.
For the high luminosity upgrade of the LHC at CERN, ATLAS is considering the addition of a High Granularity Timing Detector (HGTD) in front of the end cap and forward calorimeters at |z|=3.5 m and ...covering the region 2.4<|η|<4 to help reducing the effect of pile-up. The chosen sensors are arrays of 50μm thin Low Gain Avalanche Detectors (LGAD). This paper presents results on single LGAD sensors with a surface area of 1.3×1.3 mm2 and arrays with 2×2 pads with a surface area of 2×2 mm2 or 3×3 mm2 each and different implant doses of the p+ multiplication layer. They are obtained from data collected during a beam test campaign in autumn 2016 with a pion beam of 120 GeV energy at the CERN SPS. In addition to several quantities measured inclusively for each pad, the gain, efficiency and time resolution have been estimated as a function of the position of the incident particle inside the pad by using a beam telescope with a position resolution of few μm. Different methods to measure the time resolution are compared, yielding consistent results. The sensors with a surface area of 1.3×1.3 mm2 have a time resolution of about 40 ps for a gain of 20 and of about 27 ps for a gain of 50 and fulfil the HGTD requirements. Larger sensors have, as expected, a degraded time resolution. All sensors show very good efficiency and time resolution uniformity.
Abstract
The High Granularity Timing Detector (HGTD) will be
installed in the ATLAS detector to mitigate pile-up effects during
the High Luminosity (HL) upgrade of the Large Hadron Collider (LHC)
at ...CERN. The design of the HGTD is based on the use of Low Gain
Avalanche Detectors (LGADs), with an active thickness of
50 μm, that allow to measure with high-precision the time of
arrival of particles. The HGTD will improve the particle-vertex
assignment by measuring the track time with a resolution ranging
from approximately 30 ps at the beginning of the HL-LHC operations
to 50 ps at the end. Performances of several unirradiated, as well
as neutron- and proton-irradiated, LGAD sensors from different
vendors have been measured in beam test campaigns during the years
2018 and 2019 at CERN SPS and DESY. This paper presents the results
obtained with data recorded by an oscilloscope synchronized with a
beam telescope which provides particle position information within a
resolution of a few μm. Collected charge, time resolution and
hit efficiency are presented. In addition to these properties, the
charge uniformity is also studied as a function of the position of
the incident particle inside the sensor pad.
We report on the results of a radiation campaign with neutrons and protons of Low Gain Avalanche Detectors (LGAD) produced by Hamamatsu (HPK) as prototypes for the High-Granularity Timing Detector ...(HGTD) in ATLAS. Sensors with an active thickness of 50μm were irradiated in steps of roughly 2× up to a fluence of 3×1015neqcm−2. As a function of the fluence, the collected charge and time resolution of the irradiated sensors will be reported for operation at −30 °C.
The High-Granularity Timing Detector is a detector proposed for the ATLAS Phase II upgrade. The detector, based on the Low-Gain Avalanche Detector (LGAD) technology, will cover the pseudo-rapidity ...region of 2.4<|η|<4.0 with two end caps on each side and a total area of 6.4 m2. The timing performance can be improved by implanting an internal gain layer that can produce signals with a fast rising edge. It significantly improves the signal-to-noise ratio. The required average timing resolution per track for a minimum ionizing particle is 30 ps at the start and 50 ps at the end of the HL-LHC operation. This is achieved with several layers of LGAD. The innermost region of the detector would accumulate a 1MeV neutron-equivalent fluence up to 2.5× 1015 neq/cm2 including a safety factor of 1.5 before being replaced during the scheduled shutdowns. The addition of this new detector is expected to play an important role in the mitigation of high pile-ups at the HL-LHC. The layout and performance of the various versions of LGAD prototypes produced by Hamamatsu (HPK) have been studied by the ATLAS Collaboration. The breakdown voltages, depletion voltages, inter-pad gaps, collected charge as well as the time resolution have been measured and the production yield of large size sensors has been evaluated.
Beam test results of NDL Low Gain Avalanche Detectors (LGAD) Xiao, S.; Alderweireldt, S.; Ali, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2021, Letnik:
989
Journal Article
Recenzirano
Odprti dostop
A High-Granularity Timing Detector (HGTD) is proposed based on the Low-Gain Avalanche Detector (LGAD) for the ATLAS experiment to satisfy the time resolution requirement for the up-coming High ...Luminosity at LHC (HL-LHC). We report on beam test results for two proto-types LGADs (BV60 and BV170) developed for the HGTD. Such modules were manufactured by the Institute of High Energy Physics (IHEP) of Chinese Academy of Sciences (CAS) collaborated with Novel Device Laboratory (NDL) of the Beijing Normal University. The beam tests were performed with 5 GeV electron beam at DESY. The timing performance of the LGADs was compared to a trigger counter consisting of a quartz bar coupled to a SiPM readout while extracting reference SiPM by fitting with a Gaussian function. The time resolution was obtained as 41 ps and 63 ps for the BV60 and the BV170, respectively.
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