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Particle Physics Experiment Group

LHCb at Edinburgh
University of Edinburgh
are:
Franz Muheim F.Muheim@ed.ac.uk
Steve Playfer S.M.Playfer@ed.ac.uk
Philip Clark P.J.Clark@ed.ac.uk
Peter Clarke Peter.Clarke@ed.ac.uk
Stephan Eisenhardt S.Eisenhardt@ed.ac.uk
Yuehong Xie yxie@ph.ed.ac.uk
Young Min Kim s0679231@ph.ed.ac.uk
Colin McLean C.McLean-2@sms.ed.ac.uk
Nick Styles n.a.styles@ed.ac.uk
Ross Young r.d.young@sms.ed.ac.uk
Gemma Fardell g.c.fardell@sms.ed.ac.uk
Conor Fitzpatrick s0127440@sms.ed.ac.uk
Ailsa Sparkes ailsa.sparkes@sms.ed.ac.uk
Greig Cowan g.cowan@ed.ac.uk
Alan Walker a.walker@ed.ac.uk

Photo Detector Test facilities

LHCb-Edinburgh TWiki page

Guide to our local installation of LHCb software at PPE Edinburgh

Distributed computing at PPE Edinburgh

LHC b (public pages):
A Large Hadron Collider Beauty Experiment for Precision Measurements of CP Violation and Rare Decays

The LHC accelerator will be the most copious source of B mesons in the near future. A varity of b-hadrons (Bu, Bd, Bs, Bc as well as b-baryons) will be produced at high rate.
Operating at an average luminosity of 2*1032cm-2s-1 about 1012 pairs of b,anti-b quarks are expected to be produced in one year of data taking.

Excellent vertex resolution as well as particle identification, especially kaon-pion separation, are essential for studying the B mesons and in particular their CP asymmetries. Without particle identification decay modes with expected CP asymmetries would be seriously deluted by modes with larger branching fractions.

rich1and2_schem
LHCb: layout of RICH1 & RICH2
At LHC b particle identification of charged particles is performed, among others, by two Ring Image Cherenkov (RICH) counters where particles propagates through a medium. Due to the Cherenkov effect in this medium highly relativistic charged particles emit light in an angle relative to the trajectory of the particle where the angle is defined by the particles momentum. By measuring the momentum of the tracks, the mass of the particles can be reconstructed from the ring image information the RICH detectors provide.

Presently there are three options under study for the photodetector readout of the RICH detectors which has to cover a sensitive area of about 2.9m2 with a granualrity of the photodetectors of 2.5x2.5mm2, i.e. at the order of 400,000 readout channels:
Hybrid Photodiodes (HPD) have been proposed to be used as photodetectors and are studied in two layouts, one with the diodes subdivided in "pads" (2x2mm2) and one with the diodes subdivided in pixels (0.5x0.5mm2) using an elecrical focussing.
Multianode Photomultipliers (MaPMT) (anode size 2x2mm2) are studied as a third option.

The Edinburgh group joined the LHCb collaboration in December 1998 and collaborates strongly with the working groups at Cambridge, Glasgow, Imperial College and Oxford.

The present contributions are:

  • proponent of the MaPMT option for the RICH photodetector readout:
    • lab tests of the MaPMT R7600-03-M64
      and associated "bleeder board"
    • testbeam measurements with MaPMT and analysis
    • setup of an independent photodetector test facility at Edinburgh
  • share on coordination of RICH 2 project
there is more to follow, as:
  • physics analysis: simulation and analysis of a B decay channel to be chosen
  • ...

Selected pictures from the Glasgow lab tests 05/99:

a)&b) Hamamatsu 64-channel MaPMT R7600-03-M64 and single base,
c) mounted on linear xy-stage for single pixel test

photo_07 photo_10 photo_16

Selected pictures from the testbeam measurements 05+08/99:

ICH_proto_layout_cluster
full scale RICH 1 test setup used at X7 testbeam at CERN
(here with array of MaPMTs mounted)

a) single MaPMT with quarz lens for demagnification to reduce insensitive area,
b) testbeam cave with full scale RICH 1 vessel and array of 3x3 MaPMT mounted,
c) array of 3x3 MaPMT with array of quarz lenses and fast (40MHz) readout electronic
photo_17 photo_04 photo_20

The full electronic picture book.

Selected results from the test beams 05+08/99:

first results of the MaPMT test beam 27.7.-4.8.99:
no photos (~400kb), with photos (~77Mb)
pages(~50kb...~17Mb): 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15