october 2001general tracker meeting iekp - universität karlsruhe (th) 1 results on proton...
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October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Results on proton iResults on proton irradiation rradiation tests in Karlsruhetests in Karlsruhe
F. Hartmann
IEKP - Universität Karlsruhe (TH)
• p do Bulk & Surface Damage
Strip parameters after irrad.
• VFD for (300µm) and 500m
sensors after 10 years LHC
• Expected power for 500 m
sensors after 10 years LHC
• Outlook
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Irradiation FacilityIrradiation Facility
Compact Cyclotron at Forschungszentrum Karlsruhe
• 34 MeV protons• 1000 nA• Beam spot: 2cm O• T < -10°C• Area: 20x40cm2
• Duration: 100cm2 in 15min (1 sensor, 5e13p/cm2)
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Cold BoxCold Box
• Dry N2 atmosphere at –10°C.
• Flexible box to hold sensors, teststructures and/or modules!
• Laser focus• Simple power lines• Temp. monitor
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Simulate LHC bias conditions Simulate LHC bias conditions with respect to surface damage!with respect to surface damage!
Running @ LHC
During proton irrad.:Diode acts as a current sourcedue to the p ionising effectSOLVE: 1V potentialby applying Vbias = 1V,But AC must also be on GND!
Current source
Rp o lyDC
C C
AC
He re we ne e d p o te ntia l like in LHC 1M a t 1 A = 1V
Rp o ly
Strip c urre nt a fte r irra d
re a d o ut(o n G ND)
V b ia s
d io d e
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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How toRealize?
Simulate LHC bias conditions Simulate LHC bias conditions with respect to surface damage!with respect to surface damage!
Conductive rubber
Vbias = 1V during irrad
Bia s ring--> G ND
Rp o lyDC
ACSho rt a ll AC to b ia s (G ND)
Ba c kp la ne to + Vb ia s= 1V
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Sensors Sensors beforebefore//afterafter Irradiation Irradiation
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Fluences in the TrackerFluences in the Tracker~1.5e14 n/cm2
for 320m
~0.5e14 n/cm2
for 500m
Upper limits:UFD<500VP(-10°C)<400mW
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Irradiation SchemeIrradiation Scheme2 fluences chosen:• Inner Tracker: 1.8e14 p/cm2 (~3e14 n/cm2):
– expected for low resisitivity silicon (300µm) * 1.8 ≈ 18yLHC• Outer Tracker: 0.5e14 p/cm2 (~8e13 n/cm2):
– expected for high resistivity silicon (500m) *1.5 ≈ 15yLHC
Material (6“, 500µm thick): 1 sensor W6b from Hamamatsu 1 sensor OB2 from ST Microelectronics 6 teststructures from Hamamatsu
Biasing:1V, 12V, 100V, non
Notice: Inner Tracker fluence on Outer Tracker (500µm) sensors instead of 300µm, PRO: 1. resistivity almost right 2. No 320µm sensors present, 3. HPK will in future deliver inner 300µm sensors
CON: unusual high VFD
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Fluence MeasurementFluence Measurement
1.) Measurement by Ni-foil activation behind sensors:• Calibration at 26 MeV• Scaling with cross section to higher energies• Fluence in [p/cm2]• Hardness factor (E) scales to neutron equivalent
2.) Ileak measurement:• Temperature scaling to 20°C I(20°C)=I(T)*R(T); R(T)=(293K/T)2 ·e(-E/k(1/293K-1/T)); E=1.4eV
• I/V=*• (T=20°C)=4e-17 A/cm• Fluence in [n(1MeV)/cm2]
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Karlsruhe probing equipmentKarlsruhe probing equipment
Bias
stencil/template
Measurements take ~1.5 - 2 hours Changing of sensor ~ 5 min
Environment: –10°C, RH~1%
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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IV-Curve IV-Curve beforebefore//afterafter Irrad. Irrad.
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Power ConsumptionPower Consumption
0.0 5.0x1013 1.0x1014 1.5x1014 2.0x1014 2.5x1014 3.0x1014
0.0
50.0µ
100.0µ
150.0µ
200.0µ
250.0µ
300.0µ
350.0µ
400.0µ
Data (500m sensors, ~5kcm) Linear Fit Extrapolated value for 500m sensor
at r=60cm
(T=-10°C) = 1.2 10-18 A/cm
I /
V [
A/c
m3 ]
eq. Fluence [n/cm2]
60A/cm3 => Ileak(-10°C)=270A (W6b) => P(500V, -10°C)=135mW/sensor
Actual designed cooling power 400mW for each module (at least).
P ~ UFD I ~ d2 d ~d3
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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CV-Curve CV-Curve beforebefore//afterafter Irrad. Irrad.
0 200 400 600 800 1000 1200
0,0
5,0x1016
1,0x1017
1,5x1017
2,0x1017
2,5x1017
3,0x1017
3,5x1017
Sensor HPK Sensor ST
Sensor HPK irradiated (1.8e14 p/cm2)
Sensor ST irradiated (0.5e14 p/cm2)
Cap
acit
ance
-2 [
F-2]
Voltage [V]
UFD ~ d2 => UFD(320m) = 410V
ST and HPK sensors are stable up to Vbias=1000V after irradiation!Even strip tests were done at Vbias= 1000V!
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Hamburg ModelHamburg Model
UFD(Neff)~d2
Beneficial annealing
ga a(20°C)
Stable Damage
gcc
Reverse Annealing
gY
Y(20°C)
1 5 10 50 100 500
0.0
5.0x1011
1.0x1012
1.5x1012
2.0x1012
2.5x1012
Beneficial Annealing Stable Damage Reverse Annealing
N [c
m-3]
Time at RT [days]
PhD Thesis M. Moll:ga=(1.810.14)e-2 cm-1
a(20°C) =55hgc=(1.490.04)e-2 cm-1
c=(10.90.8)e-2 cm-1/Neff
gY=(5.160.09)e-2 cm-1
Y(20°C)=475d
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Developement of UDevelopement of UFDFD
0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5
0100200300400500600700800900
10001100
ST
Hamamatsu
Data (FS sensors) Hamburg Model
Ful
l Dep
letio
n V
olta
ge [V
]
eq. Fluence [1014n(1MeV)/cm2]
Data is fully compatible with the „Hamburg model“ fit! Predictions for different annealing scenarios possible!
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Full depletion as function of Full depletion as function of annealing time and fluenceannealing time and fluence
Fluence given at once, then annealing.
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Annealing scenario:Annealing scenario:14 days at RT each year14 days at RT each year
0 14 28 42 56 70 84 98 112 126 140 154
0
100
200
300
400
500
600
500m, 4.4k, 5e13n/cm2
" Fluence at once
320m, 2.2k, 16e13n/cm2
Ful
l Dep
letio
n V
olta
ge [
V]
Annealing Time at RT [days]
Iterative calculation of full depletion voltage
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Depletion voltages for diodeDepletion voltages for diodeminisensor and full sensorminisensor and full sensor
0 200 400 600 800 10000,0
5,0x1019
1,0x1020
1,5x1020
2,0x1020
2,5x1020
3,0x1020
~600V
~600V
~1000V
values shifted in y for comparison to compensate for different sizes
Diode 2.6e14 n/cm2
Full sensor 3e14 n/cm2
Mini sensor 2.6e14 n/cm2
Cap
acita
nce-2
[F
-2]
Voltage [V]
Future: diode measurements as reference!
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Strip Strip Leakage CurrentLeakage Current
0 5 10 15 20 25 30 35 40 45 50
0.01
0.1
1
10
100
1000
Minisensor 41
Before Irradiation After Irradiation and Annealing
(Measurement at -10°C)
Leak
age
Cur
rent
@ 4
00V
[nA
]
Strip number
As expected: Increase in leakage current!
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Bias ResistanceBias Resistance
0 5 10 15 20 25 30 35 40 45 50 55 60
1,8
1,9
2,0
2,1
2,2
2,3
Strip number
Minisensor H41
Before Irradiation Raw Data: After Irradiation and Annealing
(Measurement at -10°C) Corrected values due to high I
leak
Pol
y R
esis
tanc
e [M
] Measurement:• Apply U=2V• Measure I• Calculate R=U/I
Correction:• Measure Ileak (high after irrad)
• Correct Rc=U/(U/R+Ileak)
No change in bias resistances !
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Coupling CapacitanceCoupling Capacitance
0 5 10 15 20 25 30 35 40 45 506065707580859095
100105110115120
Strip number
Minisensor H39
Before Irradiation After Irradiation and Annealing
(Measurement at -10°C)
Cou
plin
g C
apac
itanc
e [p
F]
No change in coupling capacitances !
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Interstrip capacitance of HPK full Interstrip capacitance of HPK full sensor (1 neighbour)sensor (1 neighbour)
100 fF
<Cint>=3.2 pF
20 fF
Wedgeshaped sensor:Longer strips on the sides,but less neighbours! structure
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Interstrip CapacitanceInterstrip Capacitance
0 200 400 600 800 1000
0.15
0.30
0.45
0.60
0.75
0.90
Non irradiated: 1 MHz 100 kHz
Irradiated: 1 MHz 100 kHzIn
ters
trip
Ca
pa
cita
nce
[p
F]
Bias Voltage [V]
No change in interstrip capacitance before/after irrad.@ 1MHz.
Homogeneous interstrip distribution before/after irrad.
70 72 74 76 78 80 82 84 86 88 901,4p
1,5p
1,5p
1,6p
1,6p
1,7p
1,7p
Before Irradiation After Irradiation
Inte
rstr
ip C
apac
itanc
e [F
](2
nei
ghbo
urs)
Strip No.
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Future CMS dedicated teststand Future CMS dedicated teststand at the Cyclotron at the Cyclotron
•Scan area:20 x 50 [cm]
•Scan speed:1.25x 2.5 [cm/s]
•Maximum load:20kg
(New dedicated beam(New dedicated beamline)line)
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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Future: irradiation of a full moduleFuture: irradiation of a full module
• TEC outer, TEC inner,TOB,TIB• Longterm with high voltage, current, power
• Test of S/N, CCE, (pedestal,noise,shape)
• Test of components: sensor, electronics, mechanics
. First IEKPTEC module
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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☻☻ Conclusion Conclusion ☺☺
☻☻1. Both: ST and HPK comply with the specification of
irradiation hardness☺
2. Data fits „Hamburg model“ well and shows a decent behavior after 10 years of LHC operation☻
3. No changes in the strip parameters observed ☺
4. Future dedicated teststand promise easy access to the cyclotron ☻
5. Further plans: 300µm sensors and full modules will be irradiated!
October 2001 General Tracker Meeting IEKP - Universität Karlsruhe (TH)
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NEW:NEW: Ingot pre-qualification Ingot pre-qualification(june 2001)(june 2001)
• All measurements on diode and minisensor Save large sensors as spares!
INGOT: IV & CV on diode
To determine Vdepletion, fluence estimation and -factor.
PROCESS: Cint, Rint, leakage current, Rpoly vs. Vbias upto Vdepletion + 50V (for ~10 strips)
Hamamatsu proposed to produce a couple of additional sensors out of each new ingot for irradiation pre-qualification Special procedure in addition to the standard task.