Tracking Detectors Working Group MICE Collaboration Meeting March 30, 2004 A. Bross

Tracker Status  Outstanding Issues from Abingdon u Light Yield u Trigger timing u Channel mapping u Dead Channels u Tracking efficiency u Point Set resolution  These have now all been resolved

Tracking This event is now truly representative of a typical event

Light Yield – Tracking Efficiency  pT + 3HF (2500 ppm)  Corrected for gain variation  MP yield = pe u Agrees with extrapolation from D0  Efficiency expected due to Poisson: u 8 PE: % u 9 PE: % u 10 PE: %  Efficiency measured (0x350 data): u 5000 ppm 3HF: ± 0.39 (stat.) (8.9 pe) u 3500 ppm 3HF: ± 0.25 (stat.) (10.3 pe) u 2500 ppm 3HF: ± 0.16 (stat.)

Point Resolution  Subtracting extrapolation error from residual widths (RMS or sigma) gives point resolution (assuming all three X planes have the same resolution).  Resolution = 442 ± 4 (stat) ± 27 (syst)  m.  Depending on definition of the width of one channel (clusters complicate the issue slightly), expected resolution is between 424 and 465  m.  Resolution measured in tracker agrees with expectations.

Dead Channels  For each channel, determine the rate of hits above 4 PE on that channel.  Plot rate versus channel number and look for channels that are 0, or very low.  No channels with exactly 0 hits, however 1 with a very low rate, and another that is a little lower than its neighbours.  Worst case: 2 / 1008 = 0.2%  G4MICE assumption is 0.25%

Prototype Test Summary  The prototype fiber tracker is working well within expectations  Light Yield agrees with what was expected from extrapolations from D0 data  Dead channel fraction very low  Light yield good  Tracking efficiency very high and consistent with light yield

Progress on Mechanical Design

Cryogenics  Current plan is to use develop a VLPC cryostat using cryo- cooler u Sumitomo 451D  Each tracker would have two cryostats each holding two D0-type cassettes (2048 ch)  This arrangement may allow for shorter waveguides – 3m max. u Current prototype – 4m u 13% increase in light yield

Integration Issues  Specification of tracker mounting inside magnet still being developed  Magnetic field monitoring: u Hall probes probably can be sited inside bore u Signal/low voltage cables can be routed through patch panel though their own bulkhead connector u BUT: can monitoring be accomplished using Hall probes outside solenoid bore … simpler and fewer interfaces  Diffuser I: u Tilley: place it at ‘start’ of first correction coil u Requires ‘re-entrant’ exit window on upstream tracker  Safety Issue was raised u Simultaneous failure of H containment and safety windows could allow tracker volume to fill with H s IMPACT? –Hall probes –Vacuum pump

Technical Reference Document  All contributions to Saturday have been implemented  Require to include missing sections and redraft …  Another interation of the tracker section will happen  Restart regular phone meetings after the collaboration meeting

Cost  Capital costs of tracker and associated electronics as discussed in Osaka and FNAL  JP staff costs not counted (additional JP contribution)  US staff costs appear in ‘loaded’ capital costs  UK staff costed separately as required in the UK for reporting

Cost  Note on contingency: u Capital: s Includes contingency on US staff costs since US staff introduced by ‘loading’ capital cost u Staff: s Includes contingency on UK staff cost only since only UK staff costs explicitly ‘pulled out’  Note on cost saving option: u Construction of new VLPC cassettes ~$1M s Helpful to understand if loan of ‘spare’ D0 realistic s If tentative agreement (hedged with caveats) can be reached US contribution of $1M moves from capital to explicit contingency u Full Electronics costs $1.79M s Tracker costs: approximately $410k

Schedule: Note: tracker construction schedule could be advanced if required

MICE Stage 1.5  Beam test with Prototype  Objective u More Statistics s calibration, efficiency, uniformity u High Rate u Momentum Analysis  Target test at KEK Spring 2005

KEK π 2 Beam Line

 Slow extracted u 2 sec Flat top u 10 mm R.M.S  Yield of Pion10^5 u 1 GeV/c u 0.4 GeV/c BEAM Conditions

BESS/Super JACEE Magnet B=1T 1 week life Beam

What can we do with Magnet?  Momentum Resolution  Calibration scheme  Tracking in realistic environment u high rate, noise u Also this test allows for test of new tracker station built to final specifications s Impose QC procedures – Not done for current prototype test

TPG R&D  Hexaboards have been a problem u First – unusable u Second – better, but still problems u Third – expect delivery soon u In addition – external company (with CERN supervision) is making boards u Going to larger pads (and VIAs – the real problem) should improve quality drastically, lower cost since standard PCB process.  Full optimization u Take diffusion into effect in order to optimize readout s Do not impose OverKill u Possible cost reductions s In construction s Length of chamber and thus length solenoid

TPG front view

What’s next for TPG  Preamp gain curves  Trying to set up a TPG reconstruction “workshop” in Trieste  u Implement the combination of projections into space points. u Interface to G4MICE data format.  Early June: one week test-beam.  Mid July: one week test-beam.

Reducing the detector cost?  Main components u Field-cage u GEMs and Hexaboard u Electronics u DAQ  Is it possible to reduce their cost?

So can we save money somewhere else than in the TPG?  Diffusion with He-based mixtures can spoil the resolution in the last part of the tracking volume  First trials with track fitting show the algorithm can do perfectly well with much fewer points u Simulation and Test-beam can check this  Shorter TPG  shorter spectrometer magnet  less money?  What is the cost/m of the solenoid?

Tracker Working Group Summary  Prototype tracker performance meets all specifications u As expected based on D0 data  Mechanical design progressing well u Integration with Solenoid under development  Cryo-coolers for VLPC system now baseline u Need “Proof-of-principle” design AS SOON AS POSSIBLE u Geometry allows for shorter WG (+10% increase in LY)  Need to develop full QC procedures  Planning/preparation for KEK beam test u Second station prototype u QA procedures, connectors etc. u Measurement of basic fibre properties  TPG R&D Program continues u Test beam results soon  Simulation and reconstruction. u Yagmur’s Talk