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Scintillation counters for the CDF Muon Upgrade DPF 2000, Columbus Ohio G. Pauletta, for the CDF Collaboration. Outline : Overview upgrade objectives and the role of the scintillation counters The Run I counters Characteristics, performance and problems - PowerPoint PPT Presentation
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CDF
Aug. 20th, 2000 1
Scintillation counters for the CDF Muon Upgrade
DPF 2000, Columbus OhioG. Pauletta, for the CDF Collaboration
Outline:Overview
upgrade objectives and the role of the scintillation counters
The Run I countersCharacteristics, performance and problems
Filling the holes and extending the coverage: New countersdesign and performance
Refurbishing old countersmethod and results
CDF
Aug. 20th, 2000 2
Muon Upgrade objectives
Trigger on muons at increased luminosity ( >1032) and shorter bunch crossings (396 ns, 132 ns) Increase coverage
RUN I -------- > RUN II
CMU CMP/CSP CMX/CSX BMU/BSUCoverage 0<<0.6 0<<0.6 0.6<<1 1<<1.5drift time 800 ns 1.4 s 1.4 s 800 ns
CDF
Aug. 20th, 2000 3
The muon trigger
scintillation ctrs. serve to“time stamp” and/or reduceuncorrelated b.g. at level 1
CDF
Aug. 20th, 2000 4
Muon Upgrade subdetectors
Central Muon eXtension(CSX + CMX)
“miniskirt” (new)lower 90o
Intermediate MuonBMU + BSU + TSU (new)
Central MuonuPgrade (CSP + CMP)(new)(old)
Central Muonchambers
CDF
Aug. 20th, 2000 5
Old counter design
EMI 9815 PMT
PVT - base scintillator (NE114)
3 m long
30 cm
2 cm thick
CSPs
CSX “minskirt counter”
CSX “arch” counters
~ 2m
~ 2 m
CDF
Aug. 20th, 2000 6
New counter design
Scintillator: UPS-923A from Monokristal, Kharkov, Ukraine. Polystyrene doped with PTP(2%) and POPOP(.03%)
Ctr. type number dimensions
CSP 150 320cm x 30.5cm x 2 cmBSU 432 164 cm x 17 cm x 1.5 cm
Wls fiber: double - clad Y11 fiber from Kuraray fiber “mirrored at far end.
Hamamatsu H5783 photomultiplier + Cockroft - walton base
CDF
Aug. 20th, 2000 7
Counter readout
Wls fiber
PAD
CDF
Aug. 20th, 2000 8
New counter assembly
PAD
LED
LED
CDF
Aug. 20th, 2000 9
Counter output calibration
Each counter output is calibrated in absolute terms (number of photoelectrons/ADC channel) by exposing it to low - level pulsed light ( ~1 p.e./pulse) and locating the centroid single p.e. distribution.
CDF
Aug. 20th, 2000 10
Counter response ( in photoelectrons) to cosmic muonsis measured in steps of ~20 cm and the results are fittedto extract counter characteristics
Measurements are automated (4 ctrs at a time)Offline fit
npe(x) = n0(exp(-x/l) + r * exp(-(2L -x)/l))From the fit , one extracts:n0 (zero extrapolation)r (reflection coefficient of fiber mirrors)keeping known fiber attenuation constant at 3 m
npe
distance (x) from pmt
CDF
Aug. 20th, 2000 11
RUSSIAN L3 COUNTER ASSEMBLY AND TEST RECORDSLum gain at gain at LED
L3 n pe at PMT sens 800 v 950 v Attenuation measurement PLATEAU AMPL at
counter 315 cm s/n E-05 E+05 E+06 n 0 nend r nend' EAST WEST PAD # Voltage PLATEAU
85 24.5 5440 6.91 6.27 2.47 37.1 24.6 0.85 25.0 1 850 8.186 21.7 5436 7.35 4.69 3.44 37.5 23.8 0.76 23.0 1 23587 23.1 4515 7.93 2.62 2.98 30.3 18.3 0.66 18.0 1 950 6.988 27.7 4704 6.20 4.65 3.40 35.1 22.1 0.74 21.0 1 875 9.6
Fermi VS Dubna NPE
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
1 9
17
25
33
41
49
57
65
73
81
89
97
10
5
Fermi NPE
Dubna NPE
CSP Test Results
0
2
4
6
8
10
12
14
16
18
20
Number of photoelectrons at 20cm from end
fre
qu
en
cy
csp yield
Counter parametersand test results using cosmic muons
CDF
Aug. 20th, 2000 12
Problems with “Old” counters:efficiencies were lower than expected
CSP efficiencies CSX efficiencies
time dependence evident
CDF
Aug. 20th, 2000 13
Attenuation - length for good an bad counters
Response to cosmic muonsconfirms degradation in
attenuation-lengthand
reveals a correspondingdegradation in light yield
Or LED
CDF
Aug. 20th, 2000 14
We unwrap some counters
Good NE114 Bad NE114
Most of the countersdisplay pronounced
aging effects
CDF
Aug. 20th, 2000 15
Old Counter refurbishment:wls fiber ribbon addes to one side and routed to
existing pmt
CDF
Aug. 20th, 2000 16
CSP Repair: Work at Lab 5
CDF
Aug. 20th, 2000 17
npe at 20 cm from end
0
2
4
6
8
10
12
14
16
18
20
1 4 7 10 13 15 19 22 25 28 31 34 37 40
npe
freq
. Series1
Series2
npe at 20 cm from PMT
0
2
4
6
8
10
12
14
16
npe
frew
. Series1
Series2
Distributions of fixed counter outputs
Average npe = 16 p.e. Average npe = 58 p.e.
CDF
Aug. 20th, 2000 18
Muon Upgrade objectives
Trigger on muons at increased luminosity ( >1032) and shorter bunch crossings (396 ns, 132 ns) Increase coverage
RUN I -------- > RUN II
CMU CMP/CSP CMX/CSX BMU/BSUCoverage 0<<0.6 0<<0.6 0.6<<1 1<<1.5drift time 800 ns 1.4 s 1.4 s 800 ns