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Radiation hardness studies with Radiation hardness studies with combined irradiated MAPScombined irradiated MAPS
Dennis Doering*1, Samir Amar-Youcef 1,3,Michael Deveaux1, Melissa Domachowski1, Ingo Fröhlich1, Christian Müntz1, Sarah Ottersbach1, Joachim Stroth1, Franz M Wagner2
1 Goethe University Frankfurt am Main, 2 TU München, Forschungsquelle Heinz Maier-Leipnitz (FRM II), 3 Helmholtz Research School, Frankfurt
Outline- MAPS and combined radiation- Influence on leakage current, CCE and noise- RTS as a fake hit source- Fake hit rate after combined radiation- Conclusion
*doering@physik.uni-frankfurt.de
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
2Expected radiation dose @MVDExpected radiation dose @MVD
The CBM-experiment (at FAIR)
The CBMMicro Vertex Detectorbased on MAPS
Expected radiation dose per CBM running-year:
How does a sensor chip react on such radiation doses?
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3ClassesClasses of radiation damageof radiation damage
To be investigated and improved: Radiation hardness against…
… ionizing radiation:• Energy deposited into the electron cloud• Can ionize atoms and destroy molecules• Caused by charged particles and photons
… non-ionizing radiation:•Energy deposited into the crystal lattice•Atoms are displaced•Caused by heavy (fast leptons, hadrons),charged and neutral particles
Farnan I, HM Cho, WJ Weber, 2007. "Quantification of Actinide α-Radiation Damage in Minerals and Ceramics." Nature 445(7124):190-193.
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
4Operation principle of MAPSOperation principle of MAPS
Reset+3.3V+3.3V
Output
SiO2 SiO2 SiO2
N++ N++N+ P+
P-
P+
Diode
Epitaxial Layer
P-Well
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
5Operation principle of 3T-Pixel preamplifierOperation principle of 3T-Pixel preamplifier
C
Reset-Transistor
3.3V
Time
UK
K
IReset
ILeakage
particle
ISignal 0
1
2
3
Time
CDS=UK1- UK2
2
UK1
UK2
UK1
UK2
UK1
UK2
Threshold
Hit identified!
Measurementof leakage currentVariation: Noise
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
6Radiation tolerance against non-ionizing radiationRadiation tolerance against non-ionizing radiation
Reset+3.3V+3.3V
Output
SiO2
N++ N++N+ P+
P-
P+
SiO2
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
7Leakage current due to non-ionizing radiationLeakage current due to non-ionizing radiation
Reset+3.3V+3.3V
Output
SiO2
N++ N++N+ P+
P-
P+
SiO2
Leakage current due to defects of non-ionizing radiation
immobile
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
8Radiation tolerance against ionizing radiationRadiation tolerance against ionizing radiation
Reset+3.3V+3.3V
Output
SiO2
N++ N++N+ P+
P-
P+
SiO2Positive Charge
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
9Leakage current due to ionizing radiationLeakage current due to ionizing radiation
Reset+3.3V+3.3V
Output
SiO2
N++ N++N+ P+
P-
P+
SiO2Positive Charge
Leakage current due to ionizing radiation
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
10Radiation tolerance against combined radiationRadiation tolerance against combined radiation
Reset+3.3V+3.3V
Output
SiO2
N++ N++N+ P+
P-
P+
SiO2Positive Charge
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
11Combined radiation: Possible additional leakage currentCombined radiation: Possible additional leakage current
Reset+3.3V+3.3V
Output
SiO2
N++ N++N+ P+
P-
P+
SiO2Positive Charge
Possible additional leakage current due to combined radiation:- produced by defects of nonionizing radiation- transported by fields of ionizing radiation
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12The measurement procedureThe measurement procedure
Goal: distinguish leakage current caused by different damagesStrategy: measure systematically leakage current of differently irradiated chips
1) Not irradiated => Reference
2) Irradiated with X-rays => Leakage current due to ionizing radiation3) Irradiated with neutrons => Leakage current due to non-ionizing radiation
4) Irradiated with X-rays + neutrons => Leakage current due to combined radiation
Working assumption:
additional current = (4) - (2) - (3) + (1)
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13Determination of the leakage currentDetermination of the leakage current
Bac
helo
r T
hesi
s S
arah
Ott
ersb
ach
-50 -40 -30 -20 -10 0 10 20 30
0,01
0,1
1
10
100L
ea
ka
ge
cu
rre
nt
[fA
]
Temperature [°C]
unirradiated component non-ionising component ionising component combined component
3T-Pixel/Mimosa19
Additional leakage current component identified for combined irradiation 27 % - 137% more than expected Combined radiation damage effects orders of magnitude higher than
single radiation are not found
27%
137%
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14A short introduction into SB-PixelA short introduction into SB-Pixel
ResetTransistor
3T
Advantages: - no reset cycle/dead time necessary- Continuous read-out- usable as particle detector- leakage current compensation
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15
10
12
14
16
18
20
22
only neutron radiation additional 200kRad xray
No
ise
[e
]
T= - 20°C
Charge Collection Efficiency and Noise Charge Collection Efficiency and Noise
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1,0
only neutron radiation additional 200kRad xray
Ch
arg
e C
oll
ec
tio
n E
ffic
ien
cy
T=-20°C
Decline of CCE, driven by non-ionizing radiationIncrease of (shot) noise driven by ionizing radiation
0 0.3 0.6 1.3 2.0
Radiation dose
0 0.3 0.6 1.3 2.0
Radiation dose
SB-Pixel/Mimosa18
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
16Fake Hit Rate and Random Telegraph SignalFake Hit Rate and Random Telegraph Signal
RTS is observed after irradiation with neutrons (non-ionizing radiation) Affected RTS pixels show excessive fake hit rates
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17
0,0 0,5 1,0 1,5 2,0
1E-9
1E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0,01
fak
e h
it r
ate
radiation dose
SB -20°C SB 20°C 3T 20°C
Cooled irradiated SB-pixels show acceptable fake hit rate
Fake hit rate of 3T and SB-pixel at -20°C and 20°CFake hit rate of 3T and SB-pixel at -20°C and 20°Cfake hits / fram
e
400 k
40 k
4 k
0.4 k
…
Assume 400Mpixelin MVD
4 orders of magnitudeLower fake hit rate
Preliminary
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18Combined damage effects and fake hitsCombined damage effects and fake hits
Bac
helo
r T
hesi
s M
elis
sa D
omac
how
ski
0,0 0,5 1,0 1,5 2,0
1E-9
1E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0,01
fak
e h
it r
ate
radiation dose
SB -20°C SB 20°C SB -20°C xray SB 20°C xrayC
BM
-Goa
l
fake hits / frame
400 k
40 k
4 k
0.4 k
…
• Fake hit rate seems dominated by ionizing dose• Reasonably low rate is reached after cooling• Expect better results in radiation hardened sensors
200 kRad ionizing radiation added to neutron irradiated sensors
Preliminary
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
19SummarySummary
- Combined radiation damage effects in MAPS were evaluated for the first time.- Combined irradiated produces an additional leakage current- CCE degradation is driven by non-ionizing radiation while noise is increased
dominantly by ionizing radiation- Combined radiation damage effects orders of magnitude higher than single radiation
are not found- RTS can be an important source of fake hits- Cooled SB-pixels seem to be a good strategy to suppress fake hits- Increase of fake hit rate is mainly caused by ionizing radiation
Outlook- Annealing studies are under preparation- Irradiation with different neutron energies are planned- Tests with higher ionizing dose are proposed
Thank you for your attention
20
BackupBackup
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21
Limitation in the detection efficiency for SB-RTS-Limitation in the detection efficiency for SB-RTS-pixelspixels
10 20 30 40 50
1
2
3
4
IL
U2
I L
t
IC
ILU1
U2
I L
t
Constant threshold:=> Quantitative identification of RTS pixels is not reliable for SB-pixels=> Expect drop of identification efficiency with increasing leakage current
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
22The measurement procedureThe measurement procedure
Lnon-irr. Lnonirr.+ionizing
Lnonirr.+non-ionizingLnonirr.+non-ionizing+ionizing
neutrons
xrays
xrays
- Feasibility to extract the leakage current contributions in detail- Feasibility to identify anomalous leakage current contribution due to combined irradiation
Leakage current measurements Lx
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23
50 100 150 200 250 300 350 400 450 500charge collectedADC
0.5
1
1.5
2
2.5
seirtne
nimargo
tsihmron
50 100 150 200 250 300 350 400 450 500
50 100 150 200 250 300 350 400 450 500charge collectedADC
0.5
1
1.5
2
2.5
seirtne
nimargo
tsihmron
50 100 150 200 250 300 350 400 450 500
4 Pixel
1 Pixel
(EpiHit)
(DiodeHit)
Fe-SpectrumFe-Spectrum
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24
50 100 150 200 250 300 350 400 450 500 550 600 650 700 750charge collectedADC
0.5
1
1.5
2
2.5
seirtne
nimarg
otsihmron
50 100 150 200 250 300 350 400 450 500 550 600 650 700
50 100 150 200 250 300 350 400 450 500 550 600 650 700 750charge collectedADC
0.5
1
1.5
2
2.5
seirtne
nimarg
otsihmron
50 100 150 200 250 300 350 400 450 500 550 600 650 700
Cd-SpectrumCd-Spectrum
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
25Comparison Fe and CdComparison Fe and Cd
50 100 150 200 250 300 350 400 450 500charge collectedADC
0.5
1
1.5
2
2.5
seirtneni
margotsihmron
50 100 150 200 250 300 350 400 450 500
50 100 150 200 250 300 350 400 450 500charge collectedADC
0.5
1
1.5
2
2.5
seirtneni
margotsihmron
50 100 150 200 250 300 350 400 450 500
50 100 150 200 250 300 350 400 450 500 550 600 650 700 750charge collectedADC
0.5
1
1.5
2
2.5
seirtne
ni
margotsihmron
50 100 150 200 250 300 350 400 450 500 550 600 650 700
50 100 150 200 250 300 350 400 450 500 550 600 650 700 750charge collectedADC
0.5
1
1.5
2
2.5
seirtne
ni
margotsihmron
50 100 150 200 250 300 350 400 450 500 550 600 650 700
Three times as many electrons
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
26Tolerance against non-ionizingg radiationTolerance against non-ionizingg radiation+3.3V
Output
SiO2 SiO2
N++
N+SiO2 SiO2
P++ P++ P++
GND GND
+3.3V
Bulk damage
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
27
Tolerance against non-ionizing radiationTolerance against non-ionizing radiation+3.3V
Output
SiO2 SiO2
N++
N+SiO2 SiO2
P++ P++ P++
GND GND
+3.3V
Signal lost due to rekombination
Additional leakage current due to defects
Not movable
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
28Radiation tolerance against ionizing radiationRadiation tolerance against ionizing radiation
Reset+3.3V+3.3V
Output
SiO2
N++ N++N+ P+
P-
P+
SiO2Positive Charge
Additional leakage by electrons from SiO2
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
29Signal to Noise at T=-20°CSignal to Noise at T=-20°C
0 2 4 6 8 10
12
16
20
24
28
32
36
40
44
3T-Pixel Fe SB-Pixel Fe 3T Slow Fe 3T Cd
Sig
na
l to
No
ise
X Axis Title
0 0.3 0.6 1 2.0 0.6 1 200kRad200kRad
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
30RTS of combined irradiated sensorsRTS of combined irradiated sensors
Unexpected: RTS-amplitude goes down by 47 ADC after irradiation with ionizing dose
0 2000 4000 6000 8000 10000Time@framesD10k=10Min
300
400
500
600
700
SDClangiS@CDAD
Xray + neutrons
Only neutrons
Same
pixel
Peak not discussed here
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
31RTS in SB-pixel RTS in SB-pixel
The pixel output (CDS) show only a few fake hits, which coincide with the RTS driven change in the absolute potential (F1)
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
32Fake hit rate of 3T and SB-pixel at 0°C and 20°CFake hit rate of 3T and SB-pixel at 0°C and 20°C
Cooled SB-pixels show a satisfactory low fake hit rate
Assuming 400 Million pixel:400 000 fake hit per frame expected
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
33
0,0 0,5 1,0 1,5 2,0
1E-9
1E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0,01
fak
e h
it r
ate
radiation dose
SB 0°C SB 20°C 3T 20°C
Fake hit rate of 3T and SB-pixel at 0°C and 20°CFake hit rate of 3T and SB-pixel at 0°C and 20°C
Cooled SB-pixels show a satisfactory low fake hit rate
Assuming 400 Million pixel:400 000 fake hit per frame expected
CB
M-G
oal
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
34
0,0 0,5 1,0 1,5 2,0
1E-9
1E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0,01
fak
e h
it r
ate
radiation dose
SB 0°C SB 20°C 3T 20°C
Adding 200kRad ionizing radiation…Adding 200kRad ionizing radiation…
Bac
helo
r T
hesi
s M
elis
sa D
omac
how
ski
Fake hit rate is dominated by ionizing radiation
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35
Sensors with improved charge collection Sensors with improved charge collection efficiencyefficiency
How to escapehere?
Bigger collection diodes may improve CCE => Tested with Mi-19
Diode 1 Diode 2
The radiation hardness of MAPS is improved by fast charge collection
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36Tolerance against non-ionizing radiationTolerance against non-ionizing radiation
Mi-9
Mi-9
Mi-15
Mi-18
Mi-1
9
Mi-18: 4 x 256 x 256 Pixels, standard diode (3 x 4 µm)Mi-19: 2 x 192 x 192 Pixels, L-shaped diode
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37ResultsResults
A. Büdenbender, Bachelor Thesis
Charge collection efficiency is indeed substantially increased
But the bigger collection diodes generate more noise
T= -20 °C
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
38S/N of the sensorsS/N of the sensors
A. B
üden
bend
er, B
ache
lor
The
sis
Both MIMOSA-18 and MIMOSA-19 seem fairly radiation hardBig diodes have no advantages because of high noise
Insufficient S/N
Use beam test results fornon-irradiated chips.
Add information on CCE from Fe-55 tests.
Normalize collected charge according to CCE
Checked against beam test data with Mi15
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
39ResultsResults
A. Büdenbender, Bachelor Thesis
Mi18 looses its advantage in noise after ~1013 neq/cm²
T= +20 °C
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
40S/N of the sensorsS/N of the sensors
A. B
üden
bend
er, B
ache
lor
The
sis
At +20°C, the radiation hardness of Mi18 and Mi19 seems similar
Insufficient S/N
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
41Leakage Current of Mimosa19, Diode 1Leakage Current of Mimosa19, Diode 1
0,0 5,0x1012 1,0x1013 1,5x1013 2,0x1013
0
10
20
30
40
50
60
70 T = 20°C T = -20°C
Leak
age
Cur
rent
[ fA
]
Radiation Dose [n/cm²]
The increase of leakage currents is not negligable
A. B
üden
bend
er, B
ache
lor
The
sis
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42CCE of Mimosa19, Diode 1CCE of Mimosa19, Diode 1
0,0 5,0x1012 1,0x1013 1,5x1013 2,0x10130,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1,0
T = 20°C T = -20°C
Cha
rge
Col
lect
ion
Effi
cien
cy (
4 pi
xel)
%
Radiation Dose [n/cm²]
The CCE depends on the temperature
A. B
üden
bend
er, B
ache
lor
The
sis
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43
The Munich – Ljubljana puzzle
We irradiated at the FRM-II reactor in Munich
We irradiated at the Ljubljana triga reactor
So what?
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44CCE of Mimosa18 Munich - LjubljanaCCE of Mimosa18 Munich - Ljubljana
0,0 4,0x1012 8,0x1012 1,2x1013 1,6x1013 2,0x10130,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
Munich, T = 20°C Munich, T = -20°C Ljubljana, T = 20°C Ljubljana, T = -20°CC
harg
e C
olle
ctio
n E
ffici
ency
Radiation Dose [n/cm²]
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45CCE of Mimosa18 Munich - LjubljanaCCE of Mimosa18 Munich - Ljubljana
0,0 4,0x1012 8,0x1012 1,2x1013 1,6x1013 2,0x10130,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
Munich, T = 20°C Munich, T = -20°C Ljubljana, T = 20°C Ljubljana, T = -20°CC
harg
e C
olle
ctio
n E
ffici
ency
Radiation Dose [n/cm²]
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46Noise of MIMOSA-18, Munich - LjubljanaNoise of MIMOSA-18, Munich - Ljubljana
0,0 5,0x1012 1,0x1013 1,5x1013 2,0x10130
5
10
15
20
25
30
35
40
45
50
55
Munich, T = 20°C Munich, T = -20°C Ljubljana, T = 20°C Ljubljana, T = -20°CN
oise
[ e_ ]
Radiation Dose [n/cm²]
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
47Signal over Noise of Mimosa18Signal over Noise of Mimosa18
0,0 5,0x1012 1,0x1013 1,5x1013 2,0x10130
5
10
15
20
25
30
35
40
45E
xpec
ted
S/N
(4
pixe
ls)
Neutron Fluence [neq
/cm²]
Munich Ljubljana
Insufficient S/N
Lines to guide the eyes
T=-20°C
Ljubljana neutrons seem roughly a factor 2 more damagingthan Munich neutrons. Why?
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48
What means 10What means 101313 n neqeq/cm²? My current /cm²? My current
understandingunderstanding
1,1
Ljubljana ~0.9e13n~0.9e13n~1.8e13n
25%75%
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Dennis DoeringDennis DoeringCBM-Collaboration Meeting CBM-Collaboration Meeting
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
49
What means 10What means 101313 n neqeq/cm²? My current /cm²? My current
understandingunderstanding
1,0
Munich ~0.97e13~0.03e13
NIEL of both sources should be equal.
But Ljubljana applies four times more neutrons.
Mismatch could be caused by overlooked effectof slow neutrons. Neutron capture in boron doping?
97%3%
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Dennis DoeringDennis DoeringCBM-Collaboration Meeting CBM-Collaboration Meeting
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
50What means neutron capturingWhat means neutron capturing
slow n + 10B
Alpha
6Li
+2.31 MeV
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Dennis DoeringDennis DoeringCBM-Collaboration Meeting CBM-Collaboration Meeting
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
51Temperature effects on RTSTemperature effects on RTS
Hopkins et al.: Period and amplitude of RTS increases with temperature
Output signal of a selected MAPS pixel showing RTS
If RTS amplitude < threshold => no fake hitsHypothesis: Cooling => less RTS-Pixels? D
. Doe
ring
, Bac
helo
r T
hesi
s
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Dennis DoeringDennis DoeringCBM-Collaboration Meeting CBM-Collaboration Meeting
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
52RTS-pixels: How to identifyRTS-pixels: How to identifyt [a.u.]
UC
DS
Unambiguous RTS-pixel
1) Find the baseline of the pixel signal
2) Define a threshold
3) Scan output for segments of data above this threshold
4) If segment is found => RTS-pixel
D. D
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The
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Dennis DoeringDennis DoeringCBM-Collaboration Meeting CBM-Collaboration Meeting
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
53
RTS-pixels: Parameters in the identification RTS-pixels: Parameters in the identification algorithmalgorithm t [a.u.]
UC
DS
Ambiguous RTS-pixel
Some pixels show a“maybe RTS with smallamplitude”. Choose good threshold
UC
DS
t [a.u.]This is not an RTS-pixel
Some pixels show too fast RTS for being detected.Minimum time of RTS signature plays a role.
Same data!
D. D
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The
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Dennis DoeringDennis DoeringCBM-Collaboration Meeting CBM-Collaboration Meeting
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
54
RTS-pixels: Parameters in the identification RTS-pixels: Parameters in the identification algorithmalgorithm t [a.u.]
UC
DS
Unambiguous RTS-pixel
RTS- pixels might be not recognized because of insufficientobservation time.
Observation time: 4.5 min
UC
DS
D. D
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The
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/19
Dennis DoeringDennis DoeringCBM-Collaboration Meeting CBM-Collaboration Meeting
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
55Detected RTS-pixels over timeDetected RTS-pixels over time
Saturation value
Results presented today: ~ 5 min
Speculation:Are there two kinds of origins of RTS having different time constant?
D. D
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The
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/19
Dennis DoeringDennis DoeringCBM-Collaboration Meeting CBM-Collaboration Meeting
Split 2009Split 2009
Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
56RTS-pixels: How to identifyRTS-pixels: How to identifyt [a.u.]
UC
DS
Unambiguous RTS-pixel
1) Find the baseline of the pixel signal
2) Define a threshold:
3) Scan output for segments of data above this threshold
4) If segment is found => RTS-pixel
150 electrons reasonable threshold for detector operation
Segments of dt > 0.5 s are identified D. D
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The
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/19
Dennis DoeringDennis DoeringCBM-Collaboration Meeting CBM-Collaboration Meeting
Split 2009Split 2009
Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
57Identified RTS - pixels as function of temperatureIdentified RTS - pixels as function of temperature
Number of identified RTS - pixels is dramatically reduced by cooling
RTS pixel if signature with:
•Amplitude >150e ENC •Tmin = ~ 0.5s•Tmax= ~ 45 min
Preliminary
0,0 5,0x1012 1,0x1013 1,5x1013 2,0x1013
0,1
1
10
RT
S-P
ixel
s [%
]
Radiation dose
-20°C 0°C 20°C 40°C
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Dennis DoeringDennis DoeringCBM-Collaboration Meeting CBM-Collaboration Meeting
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
58
Chips with intrinsic leakage current compensation Chips with intrinsic leakage current compensation (SB-pixel)(SB-pixel)
IC
IL U1
U2
vdd (+3.3V)
IL
t
UCDS
t
IC, U2
t
RTS should only be visible in UCDS, if new equilibrium is being establishedSteps should be visible in U2
(Output)
Threshold
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Dennis DoeringDennis DoeringCBM-Collaboration Meeting CBM-Collaboration Meeting
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Radiation hardness studies with combined irradiated MAPSRadiation hardness studies with combined irradiated MAPS
59Spatial distribution of fake hitsSpatial distribution of fake hits
PixelNr
Pix
elN
r
low
medium
high
Fake hit rate
T=40°C
Run 18040FakeHitRateMimosa.nb
Fake hits are caused by randomly distributed hot pixels
D. D
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The
sis