micron detector testing in liverpool g. casse – o. lodge laboratory, university of liverpool
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Micron detector testing in Liverpool
G. Casse – O. Lodge Laboratory, University of Liverpool
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
Outline:Irradiation of n-in-n and p-in-n 200 µm thick Phi-type detectors Test of distortion of the charge sharing ( function) in non-homogeneously irradiated n-in-n detectors Comparison with simulations Comparison of charge collection efficiency vs voltage curves obtained with beta particles (106Ru source) and 1060 nm laser Signal to noise with SCT128-VGComparison of CCE with n and p read out strips (n-in-n vs p-in-n diode geometry)
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
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Position from Ref [mm]
Me
asu
red
flu
en
ce [
x10
13 c
m-2]
A n-in-n and a p-in-n phi detectors have been irradiated in the 24GeV/c CERN-PS beam area (Irrad1 zone). They were positioned to get a non-homogenous irradiation profile
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
The n-in-n phi-detector has been scanned using the fine spot 1060 nm laser in order to study the Neff profile and the function across the irradiated area. The manual x-y stage has a scale with 2µm step which allows the intermediate positioning with 1 µm precision. The light spot has a FWHM of about 7µm. The detector has been scanned near the outer region where the strip pitch is about 100µm. The metallisation on the backside of the detector has holes to avoid reflections of the laser light. The intermediate read-out strip screens the laser beam in the mid-strip area.
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
0
1E+12
2E+12
3E+12
4E+12
5E+12
6E+12
7E+12
8E+12
9E+12
0 100 200 300 400 500 600 700
Strip #
Neff
[cm
-3]
0
20
40
60
80
100
120
Vfd
[V]
The effective doping concentration as measured by the CCE curves in correspondence of laser illumination of different strips. The high gradient region is about from strip #550 to #600.
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
Scan across strips #517-#518
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0.8
1
1.2
0 10 20 30 40 50 60 70 80 90 100Local position [µm]
Rig
ht
cha
rge
/To
tal
cha
rge
30 volt
50 volt
150 volt
300 volt
Scan across strips #534-#535
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0.2
0.4
0.6
0.8
1
1.2
0 10 20 30 40 50 60 70 80 90 100Local position [µm]
Rig
ht c
harg
e/To
tal c
harg
e
25 volt
70 volt
200 volt
Measurement of the function in differently irradiated area of the detector: “low gradient area (irradiation about at type inversion fluence)”
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
Scan across strips #582-#583
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0.2
0.4
0.6
0.8
1
1.2
0 10 20 30 40 50 60 70 80 90 100Local position [µm]
Rig
ht
char
ge
/To
tal
char
ge
40 volt
200 volt
Scan across strips #612-#613
0
0.2
0.4
0.6
0.8
1
1.2
0 10 20 30 40 50 60 70 80 90 100Local position [µm]
Rig
ht c
harg
e/To
tal
char
ge
50 volt
150 volt
300 volt
Measurement of the function in differently irradiated area of the detector: “high gradient area”
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
Scan across strips #632-#633
0
0.2
0.4
0.6
0.8
1
1.2
0 10 20 30 40 50 60 70 80 90 100Local position [µm]
Rig
ht
char
ge
/To
tal
char
ge
50 volt150 volt300 volt
Measurement of the function in differently irradiated area of the detector: “most irradiated area”
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
ISE simulation of the electric field (300 V applied bias) in the high gradient area of an irradiated (>4.1014 cm-2) p-in-n silicon detector and signal of two neighbour strips generated by a MIP crossing mid way of the two strips
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
ISE simulation of the electric field (120 V applied bias) in the high gradient area of an irradiated (>6.1014 cm-2) n-in-n silicon detector and signal of two neighbour strips generated by a MIP crossing mid way of the two strips. The difference in signal height corresponds to the one obtained by moving the impact point of the MIP off centre by half a micron.
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
Irradiated area (>5.1014 p cm-2)
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1.0
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0 100 200 300 400 500 600Bias [V]
CCE Source (#99-102)
Laser (#101)
Irradiated area (~3.1014 cm-2)
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0.8
1.0
1.2
0 100 200 300 400 500Bias [V]
CC
E
Laser #60
Source 55-60
Comparison between CCE obtained with 1060 nm laser and 106Ru source
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
Preliminary comparison of CCE between n-in-n and p-in-n detectors: highly irradiated region. The signal was induced by 1060 nm laser. The detectors were irradiated together. Thickness of both types: 200 µm.
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1.0
1.2
0 100 200 300 400 500 600
Bias [V]
CC
E
p-in-n (High irradiation area)
n-in-n (high irradiation area)
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
Noise performances:
The measured S/N for b particle (106Ru) signal signal with SCT128VG for this detector is ~16 in the low irradiation region and ~13.5 in the higher irradiated region. The noise level is independent on the applied bias between 50 to 400 volts, as expected with irradiated silicon detectors. There is no evidence of microdischarge at any voltage. This results is preliminary: only 1/8 of the detector has been tested up to now.
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
Results with populated (12 chips) IDE hybrid and irradiated 200µm p-in-n detector
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5
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0 100 200 300 400 500
Bias [V]
No
ise
co
un
ts (
#)
Chip 4 (Irr. area)
Chip 5 (Irr. area)
Chip + fan-in noise
Microdischarge
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
Status of VELO hybrid support card (T. Smith)
5/21/02 LHCb week G. Casse – O. Lodge lab. University of Liverpool
Micron detector testing in Liverpool
Conclusions:
Distortion of the resolution due to non-homogeneous irradiation does not need correctionCCE with n-strip read-out superior at low voltages after irradiationNo evidence of microdischages up to 500 V in n-in-n (p-spray) detectors
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