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CBM – Russia meeting at ITEP, Nov 5 th 2004. Muon triggering system for the ALICE TOF cosmic tests. for the ITEP Moscow: A.Akindinov Yu.Grishuk S.Kiselev D.Mal’kevich M.Ryabinin A.Smirnitski K.Voloshin B.Zagreev. - NIM, A387, pp. 231-234, 1997 - PowerPoint PPT Presentation
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Muon triggering system for the ALICE TOF cosmic tests
for the ITEP Moscow:
A.AkindinovYu.GrishukS.KiselevD.Mal’kevichM.RyabininA.SmirnitskiK.VoloshinB.Zagreev
- NIM, A387, pp. 231-234, 1997- Patent for invention of Russia, №2142175, 1999- Preprint ITEP 11 - 03, 2003- 8th ICATPP, Villa Elba, Como, 6-10 Oct., 2003- Preprint ITEP 05 - 04, 2004- PTE, appr. for publishing, May, 2004 - NIM, submitted in Sept., 2004
CBM – Russia meeting at ITEP, Nov 5th 2004
ALICE TOFCosmic Ray Test Facility
Cosmic particle
TOF modules
Muon filter
Trigger detectors
To separate straight tracks of high-energy muons one needs at least 3 planes of trigger detectors organized in a granular structure
• The mechanical farm is already built
• Trigger counters are under construction
TOF modules may be installed in 6 different positions
ALICE TOFCosmic Tests of Detector Elements
Muon Triggering System
• scintillator plate
• dimensions 15151 cm3
• two round grooves at both surfaces
• two WLS fibers will be put into the grooves to collect light and to concentrate it on two MRS APDs
‘Tile’
WLS fiber (Kuraray Y11) and MRS APD (by CPTA, Moscow)
with 11 mm2 working area
ITEP
Assembling of a trigger detector
scintillator plate
WLS fibers inside round grooves
APDs
Completely functional trigger detectorfor the ALICE TOF Cosmic Ray Facility.
FEE card implemented.
ALICE TOFCosmic Tests of Detector Elements
Trigger Detector ITEP
ALICE TOFCosmic Tests of Detector Elements
Trigger Detector under Test ITEP
Beam to different places of the ‘tile’
Amplitude spectra
ALICE TOFCosmic Tests of Detector Elements
Construction of the Muon Triggering System
Phase 1: building the prototype of a mosaic trigger detectorThe work has been launched at ITEP
Assembly procedure
Processing the scintillator plates
ALICE TOFCosmic Tests of Detector Elements
Muon Triggering System
Mosaic stricture of the trigger detector
Light detection by high-gain MRS APD
2 MRS APDs per cell
• dense packing ensures the absence of ‘dead’ zones
• intrinsic noise of a single cell ~ 0.01 Hz
Various kinds of MRS APDsused in prototypes
• sensitive area size ~ 1 mm2
• gain ~ 106
Parameters: FE card and input signal
Ampl. 0.5 V/pC ( at 35 pF )
Noise ~ 3000 e-
Res. time of coincidence
circuit 10 – 40 ns
Working point 51 V
Thresh. 130 mV (260 fC)
~ 3.5 ph.e.
0 5 10 15 20 25 30 3510
20
30
40
50
60
70
80
90
100
110
Fourth glueingThird glueingSecond glueingFirst glueing
Efficiency scan for 32 STARs
Eff
icie
ncy
, %
STAR number0 5 10 15 20 25 30 35
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
Time resolution for 32 STARs
Fourth glueingThird glueingSecond glueingFirst glueing
Tim
e re
solu
tion
TO
F (T
1 -
T 2
) /2
, ns
STAR number
1 m2 muon detector – beam test with MIP
Close plans
for the ALICE TOF muon trigger system
1. 1 m**2 - ready ( May 2004 )
2. 7 m**2 - plans : ready mid 2005
work currently performing at ITEP: - sc. plastic has been built by “Polimersintez” now under machining at ITEP - FEE cards constr. close to finish (next week) - MRS APDs – still under choosing latest version
i.e. so far: OK
- assembly/tests – winter/spring 2005
3. 20 m**2 - full system - plans: ready mid 2006
Resumeon experience with 1 m**2 array of STARTs
1. Stable, repeatable characteristics2. Response to MIP – clear, stays far above the pedestal – - 100% efficiency3. Due to geometry – can be easily arranged in large trigger array
4. Cost – 70–140 USD/cell - now For large system ( ~ 40 cells/m**2) – 2–3 kUSD/m**2 - now
Clear prediction for cost reduction…
Will be used for cosmic muon triggering in ALICE TOF - now
Good candidate to replace RPC for high rate muon triggering
Intrinsic noise – around 10** -2 Hz/cell - now could be easily reduced to 10**-3 – 10**-4 Hz/cell - now