Entrance Muon Counter (EMC) P. Kammel, C. Ozben, D. Webber, F. Mulhauser, J. Blackburn, E. Thorsland et. al. PSI Detector group Outline of talk: Requirements Concept and hardware Readout Test program Challenges: Very high, pulsed rate Limited space and thickness Transcontinental design References: General: http://www.npl.uiuc.edu/exp/mulan/protected/TechnicalDesignReport/beam_target/beam_target.html EMC section, my Boston talk Electronics: http://www.npl.uiuc.edu/exp/mucapture/coll/daq.html: EPC readout section

Specs as of 2003 1 efficiency during BEAM ON >95%, stable within 5% ? 2 efficiency during BEAM OFF >95%, no time dependence to < 10-4 ? 3 spatial resolution ~ 5x5 mm2 4 max flux ~ 1.5 104 /mm2/s 5 max rate/wire ~ 1.2 106 /s 6 thickness in beam direction < 6 10-4 X0 7 length in beam direction <5 cm 8 active area 10x10 cm2 9 chamber frame width 2.5 cm 10 electronics continuous readout, preamp/shaper/disc frame mounted 11 time resolution 30ns FWHM 12 total charge per cm <50 mC/cm

Material budget

Rate and efficiency (2003) comments: i) ii) iii) iv) efficiency: i) very hard, really necessary? 104 /mm2/s limit pulsed effect?? CF4 mixtures (etching, recycling…) Micropattern gas detectors GEM ii) fast gas, fast electronics iii) ok iv) needs study and experiment project for 2003-2004 ! i) ii) iii) iv) efficiency: constant (within ???) during 10-20 us beam OFF period after 2-4us pulse ON efficiency stable within 10% during pulse others ? v) geometry: total thickness < 100 um, compatible with small space,relatively narrow frame

Realization Number / Diam. of Anode Wires 94 25 um Number / Diam. of Edge Wires 6 100/50 um Material of Wires Tungsten (Gold plated) Mech. Wire-Tension 0.45 - 0.6 N Wire spacing 1.0 mm Active Area 94 x 94 mm Halfgap 2.5 mm Number of Anode Planes 2 Number of Cathode Planes 3 Material of Cathode-Foils 12 um Al/Mylar/Al Material of Shielding-Foils 20 um Al/Mylar/Al Gas CF4-Isobutane 70:30

Signal and Electronics 8x MIPS CF4-isobutane mobility 1.04 cm2/Vs preamp/shaper/discriminator CMP16F chip form CMS adjust, study Table 5: signal and noise in wire chamber Conservatively, the threshold should be ~ 10x above noise and on 10% of the average signal of the Landau distribution. Thus signal to noise should be larger than 100. The above threshold assumes total charge detection, for improved timing single cluster detection is required, which needs about ~10x higher gain.

Readout Trans board 1:1 or 1:2 CMP16F LE32 CAEN TDC 200 ch 30 cm shielded twisted pair CMP16F LVDS LE32 Bernhard ECL CAEN TDC 200 ch

Readout and assembly

Construction and test program All parts at PSI for wire stringing June: HV tests July: readout of all channels July: performance test Efficiency plateau Timing behaviour Efficiency vs rate Auto correlations Reconstruction optimization Analog pulse shape (Genna) …. Probably quantifying time dependent inefficiency will be tricky Aug: beam tests Wire chambers need development time, in particular under extreme conditions. Plastic T0 counter during run for sys check and backup. Garfield simulation, undergrad project