Documents

  • 2013-09-22 TWEPP2013 by Rui Gao
    Development of precision Time-Of-Flight electronics for LHCb TORCH

    The TORCH detector is proposed for the low-momentum particle identification upgrade of the LHCb experiment. It combines Time-Of-Flight and Cherenkov techniques to achieve positive π/K/p separation up to 10 GeV/c. This requires a timing resolution of 70 ps for single photons. This paper reports on the electronics developed for such measurements, using commercial Micro Channel Plate (MCP) devices and custom ASICs (NINO and HPTDC). The intrinsic timing resolution of the electronics measured with electrical test pulses is 40 ps. With the MCP photon detector and a pulsed laser, a resolution of 90 ps has been recorded in laboratory tests and 130 ps in test beams.

    Topical Workshop on Electronics for Particle Physics (TWEPP) 2013
    Conference website   Details   Poster as pdf   Proceeding as pdf   2014 JINST 9 C02025
     dx.doi.org/10.1088/1748-0221/9/02/C02025

  • 2013-02-11 VCI2013 by Thomas Conneely, James S. Miles, Jon Howorth
    Extended lifetime MCP-PMTs: Characterisation and Lifetime measurements of ALD coated Microchannel Plates, in a sealed photomultiplier tube

    Atomic Layer Deposition (ALD) coating of Microchannel Plates (MCP) has been shown to offer significant performance advantages MCP-PMTs. ALD is a chemical process used to deposit atomic mono-layers on a substrate. A process has been developed to deposit a surface with improved secondary emission yield on to a MCP substrate. The principal advantage of a higher SEY is the ability to achieve significantly higher gain at the same operating voltage across a single MCP. Further to this, it is suspected the atomic mono-layers deposited by ALD coating prevents desorption of gaseous contaminants in the MCP glass. The ions produced during desorption are widely believed to be a direct cause of photocathode aging in MCP-PMTs, leading to the hope that ALD coating can improve MCP-PMT lifetime. To fully characterise the performance of ALD coated MCPs two MCP-PMTs were manufactured, one ALD coated and the other used as a control. Each detector’s gain, DQE, pulse shape and timing jitter were measured followed by a life test of the tubes. The ALD coated tube was found to have a higher gain at the same operating voltage, whilst being equivalent to a standard MCP in other performance characteristics. ALD coating gave a dramatically improved life time, after 5.16 C/cm2 total charge extracted, there was no measurable effect on photocathode QE, although MCP gain dropped by approximately 35%.

    Vienna Conference on Instrumentation (VCI) 2013
    Conference website   Details   Poster as pdf   Proceeding as pdf   NIM A 732, (21 December 2013) 388–391
     dx.doi.org/10.1016/j.nima.2013.07.023

  • 2011-07-04 NDIP2011 by Lucia Castillo-Garcia
    Testing micro-channel plate detectors for the particle identification upgrade of LHCb

    The TORCH, Time of internally Reflected Cherenkov Light, is proposed for the high luminosity upgrade of the LHCb experiment. The detector combines Time-of-Flight and Cherenkov techniques to achieve positive π/K/p separation on a ≥3σ level in the momentum range below 10 GeV/c. The required time resolution is ≤50 ps for single photon signal.
    In a preliminary R&D phase, we have shown that already commercially available micro-channel plate tubes with 8×8 channels fulfil the requirements. Timing properties of the tubes have been investigated with a pulsed laser diode in single photon regime. Key results from these laboratory tests are reported. An excellent timing resolution of <40 ps is achieved with an efficiency of ∼90%.

    International Conference on New Developments in Photodetection (NDIP) 2011
    Conference website   Details   Poster as pdf   Proceeding as pdf   NIM A 695, Issue 1 (11 December 2012) 398–402
    dx.doi.org/10.1016/j.nima.2011.12.021

  • 2011-06-09 TIPP2011 by Neville Harnew
    TORCH: A Large-Area Detector for Precision Time-of-Flight Measurements at LHCb

    The TORCH (Time Of internally Reflected CHerenkov light) is an innovative high-precision time-of-flight detector which is suitable for large areas, up to tens of square metres, and is being developed for the upgraded LHCb experiment. The TORCH provides a time-of-flight measurement from the imaging of photons emitted in a 1 cm thick quartz radiator, based on the Cherenkov principle. The photons propagate by total internal reflection to the edge of the quartz plane and are then focused onto an array of Micro-Channel Plate (MCP) photon detectors at the periphery of the detector. The goal is to achieve a timing resolution of 15 ps per particle over a flight distance of 10 m. This will allow particle identification in the challenging momentum region up to 20 GeV/c. Commercial MCPs have been tested in the laboratory and demonstrate the required timing precision. An electronics readout system based on the NINO and HPTDC chipset is being developed to evaluate an 8×8 channel TORCH prototype. The simulated performance of the TORCH detector for LHCb is also presented.

    International Conference on Technology and Instrumentation in Particle Physics (TIPP) 2011
    Conference website   Details   Talk as pdf   Talk as ppt   Proceeding as pdf   Phys. Proc., Vol. 37 (2012) 626–633
    dx.doi.org/10.1016/j.phpro.2012.02.409

  • 2011-04-02 DIRC2011 by Thierry Gys
    R&D status for the LHCb TORCH project

    The TORCH detector is proposed for the low-momentum particle identification upgrade of the LHCb experiment. It combines time-of-flight and Cherenkov techniques to achieve positive π/K/p separation up to 10GeV/c. This requires a timing resolution ≤70ps for single photons. The present paper reports on the status of a preliminary R&D using commercially-available micro-channel plate tubes and readout electronics based on existing front-end chips.

    International Workshop on fast Cherenkov detectors - Photon detection, DIRC design and DAQ (DIRC) 2011
    Conference website   Details   Talk as pdf   Proceeding as pdf   2011 JINST 6 C10004
    dx.doi.org/10.1088/1748-0221/6/10/C10004

  • 2010-05-02 RICH2010 by Matthew J. Charles
    TORCH: Time of flight identification with Cherenkov radiation

    TORCH is a time-of-flight detector concept using Cherenkov light to provide charged particle identification up to 10 GeV/c. The concept and design are described and performance in simulation is quantified.

    International Workshop on Ring Imaging Cherenkov Detectors (RICH) 2010
    Conference website   Details   Talk as pdf   Proceeding as pdf   NIM A 639, Issue 1 (21 May 2011) 173–176
    dx.doi.org/10.1016/j.nima.2010.09.021