1. 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: EMC section, my Boston talk
Electronics: EPC readout section

2. 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
~ /mm2/s 5
max rate/wire
~ /s 6
thickness in beam direction
< 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

3. Material budget

4. 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 ! i)
ii)
iii)
iv) efficiency:
constant (within ???) during 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

5. 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 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

6. 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.

7. 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

8. Readout and assembly

9. 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