23 research outputs found
Beam tests of a large-scale TORCH time-of-flight demonstrator
The TORCH time-of-flight detector is designed to provide particle
identification in the momentum range 2-10 GeV/c over large areas. The detector
exploits prompt Cherenkov light produced by charged particles traversing a 10
mm thick quartz plate. The photons propagate via total internal reflection and
are focused onto a detector plane comprising position-sensitive Micro-Channel
Plate Photo-Multiplier Tubes (MCP-PMT) detectors. The goal is to achieve a
single-photon timing resolution of 70 ps, giving a timing precision of 15 ps
per charged particle by combining the information from around 30 detected
photons. The MCP-PMT detectors have been developed with a commercial partner
(Photek Ltd, UK), leading to the delivery of a square tube of active area 53
53mm with a granularity of 8 128 pixels equivalent. A
large-scale demonstrator of TORCH, having a quartz plate of dimensions 660
1250 10 mm and read out by a pair of MCP-PMTs with custom
readout electronics, has been verified in a test beam campaign at the CERN PS.
Preliminary results indicate that the required performance is close to being
achieved. The anticipated performance of a full-scale TORCH detector at the
LHCb experiment is presented.Comment: 12 pages, 7 figures, Paper submitted to Nuclear Instruments & Methods
in Physics Research, Section A - Special Issue VCI 201
Status of the TORCH time-of-flight project
TORCH is a time-of-flight detector, designed to provide charged pi/K particle
identification up to a momentum of 10 GeV/c for a 10 m flight path. To achieve
this level of performance, a time resolution of 15 ps per incident particle is
required. TORCH uses a plane of quartz of 1 cm thickness as a source of
Cherenkov photons, which are then focussed onto square Micro-Channel Plate
Photomultipliers (MCP-PMTs) of active area 53 x 53 mm^2, segmented into 8 x 128
pixels equivalent. A small-scale TORCH demonstrator with a customised MCP-PMT
and associated readout electronics has been successfully operated in a 5 GeV/c
mixed pion/proton beam at the CERN PS facility. Preliminary results indicate
that a single-photon resolution better than 100 ps can be achieved. The
expected performance of a full-scale TORCH detector for the Upgrade II of the
LHCb experiment is also discussed.Comment: 9 pages, 6 figures, Paper submitted to Nuclear and Methods A :
Proceedings of the 10th International Workshop on Ring Imaging Cherenkov
Detectors (RICH 2018), Moscow, Russia, July 29 to August 4 201
LHCb Upgraded RICH 1 Engineering Design Review Report
During the Long Shutdown 2 of the LHC, the LHCb collaboration will replace the upstream
Ring Imaging Cherenkov detector (RICH 1). The magnetic shield of the current RICH 1
will be modified, new spherical and plane mirrors will be installed and a new gas enclosure
will be manufactured. New photon detectors (multianode photomultiplier tubes) will be
used and these, together with their readout electronics, require a new mechanical support
system. This document describes the new optical arrangement of RICH 1, its engineering
design, installation and alignment. A summary of the project schedule and institute
responsibilities is provided
LHCb Upgraded RICH 1 Engineering Design Review Report
During the Long Shutdown 2 of the LHC, the LHCb collaboration will replace the upstream
Ring Imaging Cherenkov detector (RICH 1). The magnetic shield of the current RICH 1
will be modified, new spherical and plane mirrors will be installed and a new gas enclosure
will be manufactured. New photon detectors (multianode photomultiplier tubes) will be
used and these, together with their readout electronics, require a new mechanical support
system. This document describes the new optical arrangement of RICH 1, its engineering
design, installation and alignment. A summary of the project schedule and institute
responsibilities is provided
A Micrometric Positioning Sensor for Laser-Based Alignment
The Compact Linear Collider requires 10 ÎĽm accuracy over 200m for the alignment of its components. Since current techniques based on stretched wire or water level are difficult to implement, other options are under study. We propose a laser alignment system using positioning sensors made of camera/shutter assemblies. The goal is to implement such a positioning sensor. The corresponding studies comprise design and calibration as well as investigations of measurement accuracy and precision. On the one hand, we describe mathematically the laser beam propagation, its interaction with the shutter and image processing. On the other hand, we present experiments done with the prototype of a positioning sensor. As a result, we give practical suggestions to build the positioning sensors and we describe a calibration protocol to be applied to all sensors before measuring. In addition, we deliver estimates for measurement accuracy and precision. Our work provides the first steps towards a full alignment system
Experiment of Laser Pointing Stability on Different Surfaces to validate Micrometric Positioning Sensor
CLIC requires 10 ÎĽm precision and accuracy over 200m for the pre-alignment of beam related components. A solution based on laser beam as straight line reference is being studied at CERN. It involves camera/shutter assemblies as micrometric positioning sensors. To validate the sensors, it is necessary to determine an appropriate material for the shutter in terms of laser pointing stability. Experiments are carried out with paper, metal and ceramic surfaces. This paper presents the standard deviations of the laser spot coordinates obtained on the different surfaces, as well as the measurement error. Our experiments validate the choice of paper and ceramic for the shutter of the micrometric positioning sensor. It also provides an estimate of the achievable precision and accuracy of the determination of the laser spot centre with respect to the shutter coordinate system defined by reference targets
Pixel hybrid photon detector magnetic distortions characterization and compensation
The LHCb experiment requires positive kaon identification in the momentum range 2-100 GeV/c. This is provided by two ring imaging Cherenkov detectors. The stringent requirements on the photon detectors are fully satisfied by the novel pixel hybrid photon detector, HPD. The HPD is a vacuum tube with a quartz window, S20 photo-cathode, cross-focusing electron optics and a silicon anode encapsulated within the tube. The anode is a 32*256 pixels hybrid detector, with a silicon sensor bump-bonded onto a readout chip containing 8192 channels with analogue front-end and digital read-out circuitry. An external magnetic field influences the trajectory of the photoelectrons and could thereby degrade the inherent excellent space resolution of the HPD. The HPDs must be operational in the fringe magnetic field of the LHCb magnet. This paper reports on an extensive experimental characterization of the distortion effects. The characterization has allowed the development of parameterisations and of a compensation algorithm. A calibration procedure based on the imaging of pre-defined test patterns that has been developed for the RICH detectors is also proposed
LHCb Upgraded RICH 2 Engineering Design Review Report
https://cds.cern.ch/record/215885
The TORCH time-of-flight detector
The TORCH detector is a time-of-flight system that is being developed for use in particle physics experiments with the aim of providing particle identification, over a wide area, in the momentum range 2 to 10 GeV/c. The detector exploits prompt Cherenkov light produced by charge particles traversing a 10 mm thick quartz plate. Photons propagate via total-internal reflection and are focussed onto a detector plane comprising position-sensitive micro-channel plate photomultiplier (MCP-PMT) detectors. The goal is to achieve a resolution of 15 ps per particle by combining information from around 30 detected photons, given a single-photon resolution of 70 ps. The MCP-PMT detectors have been developed with a commercial partner (Photek), leading to the delivery of a square tube with a 53-by-53 mm active area and 8-by-128 pixel equivalent. A small-scale TORCH demonstrator has been operated in beam tests and preliminary results indicate a single-photon resolution better than 100 ps. Progress towards a larger-scale system with 11 MCP-PMTs is presented