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The LHCb upgrade I
Authors:
LHCb collaboration,
R. Aaij,
A. S. W. Abdelmotteleb,
C. Abellan Beteta,
F. Abudinén,
C. Achard,
T. Ackernley,
B. Adeva,
M. Adinolfi,
P. Adlarson,
H. Afsharnia,
C. Agapopoulou,
C. A. Aidala,
Z. Ajaltouni,
S. Akar,
K. Akiba,
P. Albicocco,
J. Albrecht,
F. Alessio,
M. Alexander,
A. Alfonso Albero,
Z. Aliouche,
P. Alvarez Cartelle,
R. Amalric,
S. Amato
, et al. (1298 additional authors not shown)
Abstract:
The LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their select…
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The LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software.
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Submitted 10 September, 2024; v1 submitted 17 May, 2023;
originally announced May 2023.
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Performance of the LHCb RICH detectors during LHC Run 2
Authors:
R. Calabrese,
M. Fiorini,
E. Luppi,
L. Minzoni,
I. Slazyk,
L. Tomassetti,
M. Bartolini,
R. Cardinale,
F. Fontanelli,
A. Petrolini,
A. Pistone,
M. Calvi,
C. Matteuzzi,
A. Lupato,
G. Simi,
M. Kucharczyk,
B. Malecki,
M. Witek,
S. Benson,
M. Blago,
G. Cavallero,
A. Contu,
C. D'Ambrosio,
C. Frei,
T. Gys
, et al. (57 additional authors not shown)
Abstract:
The performance of the ring-imaging Cherenkov detectors at the LHCb experiment is determined during the LHC Run 2 period between 2015 and 2018. The stability of the Cherenkov angle resolution and number of detected photons with time and running conditions is measured. The particle identification performance is evaluated with data and found to satisfy the requirements of the physics programme.
The performance of the ring-imaging Cherenkov detectors at the LHCb experiment is determined during the LHC Run 2 period between 2015 and 2018. The stability of the Cherenkov angle resolution and number of detected photons with time and running conditions is measured. The particle identification performance is evaluated with data and found to satisfy the requirements of the physics programme.
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Submitted 26 May, 2022;
originally announced May 2022.
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A Brewster route to Cherenkov detectors
Authors:
Xiao Lin,
Hao Hu,
Sajan Easo,
Yi Yang,
Yichen Shen,
Kezhen Yin,
Michele Piero Blago,
Ido Kaminer,
Baile Zhang,
Hongsheng Chen,
John Joannopoulos,
Marin Soljačić,
Yu Luo
Abstract:
The Cherenkov effect enables a valuable tool, known as the Cherenkov detector, to identify high-energy particles via the measurement of the Cherenkov cone. However, the sensitivity and momentum coverage of such detectors are intrinsically limited by the refractive index of the host material. Especially, identifying particles with energy above multiple gigaelectronvolts requires host materials with…
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The Cherenkov effect enables a valuable tool, known as the Cherenkov detector, to identify high-energy particles via the measurement of the Cherenkov cone. However, the sensitivity and momentum coverage of such detectors are intrinsically limited by the refractive index of the host material. Especially, identifying particles with energy above multiple gigaelectronvolts requires host materials with a near-unity refractive index, which are often limited to large and bulky gas chambers. Overcoming this fundamental material limit is important for future particle detectors yet remains a long-standing scientific challenge. Here, we propose a different paradigm for Cherenkov detectors that utilizes the broadband angular filter made from stacks of variable one-dimensional photonic crystals. Owing to the Brewster effect, the angular filter is transparent only to Cherenkov photons from a precise incident angle, and particle identification is achieved by mapping each Cherenkov angle to the peak-intensity position of transmitted photons in the detection plane. This unique property of the angular filter is exceptionally beneficial to Cherenkov detection as it enables the realization of a non-dispersive pseudo refractive index over the entire visible spectrum. Moreover, such a pseudo refractive index can be flexibly tuned to arbitrary values, including those close to unity. Our angular-selective Brewster paradigm offers a feasible solution to implement compact and highly sensitive Cherenkov detectors especially in beam lines and it can cover a wide momentum range using readily available dielectric materials.
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Submitted 26 July, 2021;
originally announced July 2021.
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A Comparison of CPU and GPU implementations for the LHCb Experiment Run 3 Trigger
Authors:
R. Aaij,
M. Adinolfi,
S. Aiola,
S. Akar,
J. Albrecht,
M. Alexander,
S. Amato,
Y. Amhis,
F. Archilli,
M. Bala,
G. Bassi,
L. Bian,
M. P. Blago,
T. Boettcher,
A. Boldyrev,
S. Borghi,
A. Brea Rodriguez,
L. Calefice,
M. Calvo Gomez,
D. H. Cámpora Pérez,
A. Cardini,
M. Cattaneo,
V. Chobanova,
G. Ciezarek,
X. Cid Vidal
, et al. (135 additional authors not shown)
Abstract:
The LHCb experiment at CERN is undergoing an upgrade in preparation for the Run 3 data taking period of the LHC. As part of this upgrade the trigger is moving to a fully software implementation operating at the LHC bunch crossing rate. We present an evaluation of a CPU-based and a GPU-based implementation of the first stage of the High Level Trigger. After a detailed comparison both options are fo…
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The LHCb experiment at CERN is undergoing an upgrade in preparation for the Run 3 data taking period of the LHC. As part of this upgrade the trigger is moving to a fully software implementation operating at the LHC bunch crossing rate. We present an evaluation of a CPU-based and a GPU-based implementation of the first stage of the High Level Trigger. After a detailed comparison both options are found to be viable. This document summarizes the performance and implementation details of these options, the outcome of which has led to the choice of the GPU-based implementation as the baseline.
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Submitted 4 January, 2022; v1 submitted 9 May, 2021;
originally announced May 2021.
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High rate tests of the photon detection system for the LHCb RICH Upgrade
Authors:
Michele Piero Blago,
Floris Keizer
Abstract:
The photon detection system for the LHCb RICH Upgrade consists of an array of multianode photomultiplier tubes (MaPMTs) read out by custom-built modular electronics. The behaviour of the whole chain was studied at CERN using a pulsed laser. Threshold scans were performed in order to study the MaPMT pulse-height spectra at high event rates and different photon intensities. The results show a reduct…
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The photon detection system for the LHCb RICH Upgrade consists of an array of multianode photomultiplier tubes (MaPMTs) read out by custom-built modular electronics. The behaviour of the whole chain was studied at CERN using a pulsed laser. Threshold scans were performed in order to study the MaPMT pulse-height spectra at high event rates and different photon intensities. The results show a reduction in photon detection efficiency at 900 V bias voltage, marked by a 20 % decrease in the single-photon peak height, when increasing the event rate from 100 kHz to 20 MHz. This reduction was not observed at 1000 V bias voltage.
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Submitted 8 January, 2018;
originally announced January 2018.