This article presents a new bulk radiation damage model for p-type silicon for use in Synopsys Sentaurus TCAD. The model is shown to provide agreement between experiment and simulation for the ...voltage dependence of the leakage current and the charge collection efficiency, for fluences up to 8×10151MeVneq∕cm2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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.
We performed a detailed study of the timing performance of the LHCb VELO Timepix3 Telescope with a 180 GeV/c mixed hadron beam at the CERN SPS. A twofold method was developed to improve the ...resolution of single-plane time measurements, resulting in a more precise overall track time measurement. The first step uses spatial information of reconstructed tracks in combination with the measured signal charge in the sensor to correct for a mixture of different effects: variations in charge carrier drift time; variations in signal induction, which are the result of a non-uniform weighting field in the pixels; and lastly, timewalk in the analog front-end. The second step corrects for systematic timing offsets in Timepix3 that vary from −2 to 2 ns. By applying this method, we improved the track time resolution from 438(16) ps to 276(4) ps.
Abstract
A comprehensive study of the spatial resolution and detection efficiency of sensor prototypes developed for the LHCb VELO upgrade is presented. Data samples were collected at the CERN SPS H8 ...beam line using a hadron mixture of protons and pions with momenta of approximately 180 GeV/c. The sensor performance was characterised using both irradiated and non-irradiated sensors. Irradiated samples were subjected to a maximum fluence of 8 × 10
15
1 MeV n
eq
cm
-2
, of both protons and neutrons. The spatial resolution is measured comparing the detected hits to the
position as predicted by tracks reconstructed by the Timepix3 telescope. The resolution is presented for different applied bias voltages and track angles, sensor thickness and implant size.
An extensive sensor testing campaign is presented, dedicated to measuring the charge collection properties of prototype candidates for the Vertex Locator (VELO) detector for the upgraded LHCb ...experiment. The charge collection is measured with sensors exposed to fluences of up to 8×1015 1 MeV neq cm-2, as well as with nonirradiated prototypes. The results are discussed, including the influence of different levels of irradiation and bias voltage on the charge collection properties. Charge multiplication is observed on some sensors that were nonuniformly irradiated with 24 GeV protons, to the highest fluence levels. An analysis of the charge collection near the guard ring region is also presented, revealing significant differences between the sensor prototypes. All tested sensor variants succeed in collecting the minimum required charge of 6000 electrons after the exposure to the maximum fluence.
Abstract
The timing performance of silicon sensors bump-bonded to Timepix3 ASICs is investigated, prior to and after different types of irradiation up to 8 × 10
15
1 MeV n
eq
cm
−2
. The sensors ...have been tested with a beam of charged particles in two different configurations, perpendicular to and almost parallel to the incident beam. The second approach, known as the grazing angles method, is shown to be a powerful method to investigate not only the charge collection, but also the time-to-threshold properties as a function of the depth at which the charges are liberated.
LHCb VELO Timepix3 telescope Akiba, K.; Beuzekom, M. van; Boterenbrood, H. ...
Journal of instrumentation,
05/2019, Volume:
14, Issue:
5
Journal Article
Peer reviewed
Open access
The LHCb VELO Timepix3 telescope is a silicon pixel tracking system constructed initially to evaluate the performance of LHCb VELO Upgrade prototypes. The telescope consists of eight hybrid pixel ...silicon sensor planes equipped with the Timepix3 ASIC . The planes provide excellent charge measurement, timestamping and spatial resolution and the system can function at high track rates. This paper describes the construction of the telescope and its data acquisition system and offline reconstruction software. A timing resolution of 350 ps was obtained for reconstructed tracks. A pointing resolution of better than 2\mum was determined for the 180 GeV/c mixed hadron beam at the CERN SPS . The telescope has been shown to operate at a rate of 5 million particles s−1ċcm−2 without a loss in efficiency.
Precise knowledge of the location of the material in the LHCb vertex locator (VELO) is essential to reducing background in searches for long-lived exotic particles, and in identifying jets that ...originate from beauty and charm quarks. Secondary interactions of hadrons produced in beam-gas collisions are used to map the location of material in the VELO. Using this material map, along with properties of a reconstructed secondary vertex and its constituent tracks, a p-value can be assigned to the hypothesis that the secondary vertex originates from a material interaction. A validation of this procedure is presented using photon conversions to dimuons.
Abstract
The thermal properties of the LHCb Vertex Locator (VELO) are studied using the real-time detector alignment procedure. The variation of the position and orientation of the detector elements ...as a function of the operating temperature of the VELO is presented. This study uses a dataset collected by the LHCb experiment during a VELO temperature scan performed at the end of LHC Run 2 (October 2018). Significant shrinkage of the VELO modules is observed at the operating temperature of -30°C compared to the laboratory measurements on a single module taken at a range of temperatures from +45°C to -25°C. The thermal shrinkage expected from the extrapolation of laboratory measurements to lower temperatures, and the results of this alignment study are in good agreement.
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