TE/MPE/EM/PMT activity Rui de Oliveira on behalf of PCB workshop team 29/11/20121.
15/07/2010Rui De Oliveira1 Update on large size GEM manufacturing Rui de Oliveira.
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15/07/2010 Rui De Oliveira 1 Update on large size GEM manufacturing Rui de Oliveira
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Transcript of 15/07/2010Rui De Oliveira1 Update on large size GEM manufacturing Rui de Oliveira.
Rui De Oliveira 115/07/2010
Update on large size GEM manufacturing
Rui de Oliveira
Rui De Oliveira 2
Summary
Process Characterization Some pictures Large volume production outside CERN
15/07/2010
Rui De Oliveira 3
GEM single mask process
15/07/2010
Chemical Polyimide etching
Second Polyimide etching
Copper electro etching
Stripping
reality
Rui De Oliveira 415/07/2010
connected Non etched Top Electrode Lower voltage than the Chemical reaction
+3V
Resist layer
+3V 0V
Bath at +3V -everything at ground will be protected -everything at +3V will be chemically etched - An example of active corrosion protection
Starting structure
Conventional isotropic metal etching
The hole is created but still an angle in the copper
With over etch
Going back to Polyimide etching for 30 secThe hole become bi-conical
Charcaterisation
10
Introducing GEM #1 – electrodes…
11
TOP
BOTTOM
Introducing GEM #2 – electrodes…
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TOP
BOTTOM
Introducing GEM #3 – electrodes…
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TOP
BOTTOM
…and cross section pictures (1)
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TOP
BOTTOM
Sample 1
Sample 2
…and cross section pictures (2)
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TOP
BOTTOM
Sample 3
Sample 4
Preparing the experimental setup
16
Drift
GEM
Anode
3.05 mm
2.15 mm
• GEM active area: 10 x 10 cm2
• Gas mixture: Ar/CO2 70/30• Gas flow: ~ 5 l/h• Water content: ~ 100 ppm H2O• Radiation source: Cu X–ray tube
Taking spectra
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• Run_0110• Both GEMs in “open–bottom” config• Ed = 2 kV/cm• Ei = 3 kV/cm• DVGEM = 480 V• Energy resolution = 18.4 %
FWHM/peak @ 8.04 keV
• Run_0104• Both GEMs in “open–top” config• Ed = 2 kV/cm• Ei = 3 kV/cm• DVGEM = 480 V• Energy resolution = 19.5 %
FWHM/peak @ 8.04 keV
0 250 500 750 1000 1250
0
100
200
300
400
AD
C c
oun
ts
ADC channel
Run_0104
0 250 500 750 1000 1250
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
AD
C c
oun
ts
ADC channel
Run_0110
Measuring the gain curves
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• Ed = 2 kV/cm
• Ei = 3 kV/cm
• Ratebottom ~ 21 kHz/mm2
• Ratetop ~ 18 kHz/mm2
• Spark Vbottom ~ 540 V
• Spark Vtop ~ 530 V
• Max Gbottom ~ 1390
• Max Gtop ~ 1080
340 360 380 400 420 440 460 480 500 520 54010
100
1000
Ga
in
DV GEM [V]
Open-bottomOpen-top
Preparing the experimental setup
19
Drift
GEM3T
Anode
3.25 mm
• GEMs active area: 10 x 10 cm2
• Gas mixture: Ar/CO2 70/30• Gas flow: ~ 5 l/h• Radiation: Ag X–ray tube, Cu filter• 2D (X–Y) readout, all strips shorted• GEMs in open–bottom configuration• HV provided by voltage divider• 2 HV filters on the line (600 k total)
GEM3B
GEM2T
GEM2B
GEM1T
GEM1B
2.215 mm
2.225 mm
2.15 mm
Taking spectra
20
• Ed = 2.09 kV/cm
• DVGEM1 = 391 V
• Et1 = 3.09 kV/cm
• DVGEM2 = 354 V
• Et2 = 3.08 kV/cm
• DVGEM3 = 309 V
• Ei = 3.19 kV/cm
• Rate ~ 2.9 kHz
• Energy resolution=20.6%FWHM/peak @ 8.04 keV
0 250 500 750 1000 1250 1500 1750 2000
0
100
200
300
400
500
600
AD
C c
ou
nts
ADC channel
Measuring the gain curve
21
• Ed ~ 2 kV/cm
• Et1 ~ 3 kV/cm
• Et2 ~ 3 kV/cm
• Ei ~ 3 kV/cm
• Rate ~ 420 kHz
3400 3600 3800 4000 4200 4400 460010
100
1000
10000
Open-bottom
Ga
in
DV divider [V]
Checking the time stability
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0 1000 2000 3000 4000 5000 600098
99
100
101
102
103
Open-bottom config. p9
Re
lativ
e g
ain
Time [s]
• Cu X–rays
• 2 mm ø collimator
• Ni #1 absorber
• DVdiv = 4200 V
• gain ~ 2560
• rate = 300 Hz
• T = (2000 ± 900) s
• DG = (1.7 ± 0.2) %
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