Construction and Quality control of large scale GEM detectors
description
Transcript of Construction and Quality control of large scale GEM detectors
Construction and Quality control of large scale GEM detectors
On behalf on the collaboration GEM for CMS
Status
Prototype I Prototype IINew NS2 technic assembly
4 prototypes produced
NS2 assembly technic
10 to 15mm
Readout connector
O-ring
Drift electrode
Free to slide
External screws to adjuststretching
GND
GND
GEM attaching structure(4 pieces defining gaps)Embedded nutO-ring
Rui De Oliveira GEM workshop IV
GEM stack ready
Inserting drift board
Install pulling screws
• Install 50 pulling screws
Oring installation
Closing with readout board
• Colsing with the readout board 50 screws.
Producing 6 new NS2 Large scale detectors
External frame
Produced in several pieces, then glued together.
GEM foils ready, waiting for the readout and drift boards. Assembly next week.
GEM foils quality control
• Sector to test from -50V to -500V by step of 50V.
• High voltage applied on the top, bottom and first neighbors sectors connected to ground.
• Measuring the leakage current
Expected leakage current
HV (-500V)
Leakage current
• Kapton resisitvity ~1019ohm.m• Air resistivity ~1016ohm.m
• R// = Rkapton x Rair / (Rkapton +Rair )
• R//(60µm)~1016 x 60.10-6 = 6. 1011ohm
• Iexpected~ 500/ R//(60µm) = 0.8 nA
RKaptonRair
RESULTS0 100 200 300 400 500 600
-0.4
-0.35
-0.3
-0.25
-0.2
-0.15
-0.1
-0.05
0
sector1sector2secteur3secteur4secteur5secteur6secteur7secteur8secteur9secteur10
0 100 200 300 400 500 600
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
sector2secteur3secteur4secteur5secteur6secteur7secteur8secteur9
GEM1
GEM2
0 100 200 300 400 500 600
-5
-4.5
-4
-3.5
-3
-2.5
-2
-1.5
-1
-0.5
0
sector1sector2secteur3secteur4secteur5secteur6secteur7secteur8secteur9secteur10
GEM3
0 100 200 300 400 500 600
-2.5
-2
-1.5
-1
-0.5
0
sector1sector2secteur3secteur4secteur5secteur6secteur7secteur8secteur9secteur10
GEM4
HV (Volts) HV (Volts)
HV (Volts)HV (Volts)
I (nA)
I (nA) I (nA)
I (nA)
Gain Uniformity Control Set up
Eta Sector 4
X Position (mm)
Peak Position (ADC counts) 15 slices ->1 slice ~ 3cm
Eta Sector 5
X Position (mm)
Peak Position (ADC counts)
Eta Sector 6
X Position (mm)
Peak Position (ADC counts)
Eta Sector 7
X Position (mm)
Peak Position (ADC counts)
Eta Sector 8
X Position (mm)
Peak Position (ADC counts)
Slice N°1
Slice N°2
PeakPosition Variation (%)
Uniformity Plot
Uniformity TOP view
Conclusion
• Construction of 6 large scale production prototypes is going on
• Improvements made on mechanical assembly (NS2 technic and flat boards)
• Powerfull tool to check gain uniformity is available