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Evaluation of Characteristics of Hamamatsu Low-Gain Avalanche Detectors
Sayaka Wada1, Kazuhiko Hara1, Kyoji Ohnaru1, Junki Suzuki1, Yoshinobu Unno2, Koji Nakamura2, Kazunori Hanagaki2, Yoichi Ikegami2,
Kazuhisa Yamamura3, Shintaro Kamada3, Yuhei Abo3, Hitomi Tokutake4, Daiki Yamamoto5
University of Tsukuba1, KEK2, HPK3, Tokyo Institute of Technology4, Osaka University5
Session113 HSTD11 at OIST, Japan
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
+Talk Outline
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
2
p Brief Introduction of LGAD
p Samples from HPK
p IV/CV Measurements
p Charge Collection Measurements
p Summary
+ Introduction
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
3
Low Gain Avalanche Detectorp Uniform high electric field @ N+-P+ junction (thin multiplication layer)
p Avalanchep Low Gain (~10) p Optimum S/N for good timing (<50ps)p Thinner detector possible
To realize 4D (even 5D) detectorgood for position and time measurements
P bulk
P+ Layer
Electric FieldP+ Electrode
Al
PInsulator
N+
+Hamamatsu LGAD
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
p Samples from HPKp Monitor Diode
p Chip Size: 2.5mm × 2.5mmp Window 1mmφ
p Stripp Chip Size: 6.0mm × 12mmp Strip Pitch: 80μm
p Dose of P+ layerp Low to high; A-B-C-D (HPK confidential)
p Active thicknessp 50μm or 80μm
4
Monitor Diode Strip
SampleName
P+ DoseLight>dense
PhysicalThickness [μm]
ActiveThickness [μm]
50A A
150
5050B B50C C50D D80A A
8080B B80C C80D D
+Monitor Diode IV
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
5
p Leakage (LED OFF) ~nA
p IR LED response (LED ONOFF)p Gain
p More P+ dose, Lower Voltagep Jumps @ ~30V
p Breakdown Voltagep 80μm is higher than 50μmp More P+ dose, Lower Voltage
p Dose of P+ layerp A, B: too weak?p C, D: good
p Active thicknessp 50μm looks better than 80μm
0 100 200 300 400 500 600 700 80011−10
10−10
9−10
8−10
7−10
6−10
5−10
0 100 200 300 400 500 600 700 80011−10
10−10
9−10
8−10
7−10
6−10
5−10
IR-LED ON-OFF
Leakage (LED OFF)
D C
D C B A
Curr
ent [
A]Cu
rren
t [A]
Voltage [V]
@20℃
Active thickness50μm
Active thickness80μm
+Wavelength Dep. of IV Curve 6
-Voltage [V]0 10 20 30 40 50 60 70 80 90 100
Cur
rent
[A]
8−10
8−10×2
8−10×3
8−10×4
8−10×5
8−10×68−10×7
7−10
Infra-red GreenRed Blue
-Voltage [V]0 10 20 30 40 50 60 70 80 90 100
Cur
rent
[A]
8−10
8−10×2
8−10×3
8−10×4
8−10×5
8−10×68−10×7
7−10
Infra-red GreenRed Blue
〜〜Absorption Depth
0.5/ 2.0/ 3.0/ 20 μm
@20℃
Wave Length 464/ 565/ 627/ 850 nm
-Voltage [V]0 100 200 300 400 500 600
Cur
rent
[A]
10−10
9−10
8−10
7−10
6−10
5−10 Infra-redRedGreenBlueLeakage
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
80D80A 80D
p 0〜500Vp Curves normalized @10Vp Longer W.L., larger currentp Breakdown Voltage has no W.L. dep.
p 0〜100Vp Curves normalized @10Vp More P+-region dose & Longer W.L., Larger Currentp More P+-region dose, Higher Voltage @ ends of jumps
+
〜〜0 10 20 30 40 50 60 70 80 90 1000
0.20.40.60.81
1.21.41.61.82
9−10×
80A
80B
80C
80D
0 100 200 300 400 500 600 700 80011−10
10−10
9−10
8−10
80A
80B
80C
80D
Bulk Capacitance
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
7
p VFD in agreement with IV (25-35V)
p Depletion Stepsp 1st. Depletion: side regionp 2nd. Depletion: multiplication layer
p More P+ dose, Higher depletion voltagep 3rd. Depletion: bulk
p 2nd. depletion voltage depends on the dose of P+ layer
Capa
cita
nce[
F]
Voltage [V]
Capa
cita
nce[
F]
@1500Hz
Voltage [V]
Active thickness80μm
Active thickness80μm
+ IV after γ-ray Irradiation
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
8
p 24 Nov. 20 Dec. 2016 @ QST, Japanp 0.1/1.0/2.5 MGy
p Leakage increase but no P+ dose dep.p γ-ray make only surface damage
p Gain retains
0 100 200 300 400 500 600 700 80010−10
9−10
8−10
7−10
6−10
5−10
0 100 200 300 400 500 600 700 80010−10
9−10
8−10
7−10
6−10
5−10
Voltage [V]
Curr
ent [
A]
Curr
ent [
A]
IR-LED ON-OFF
Leakage(LED OFF)
Non-irrad.
γ-irrad.
Non-irrad.
γ-irrad.
0
2.5
@-20℃
Monitor Diode50D
Monitor Diode80D
+ IV after Neutron Irradiation
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
9
p 15 Dec. 2016 @ Ljubljana, Sloveniap 0.3/1.0/3.0 ×1015 1-MeV neq/cm2
p After 60℃-80min. annealing
p Gain dropsp Requires higher voltage (depends on fluence)p e.g. 50D (280V→700V) Gain~5
0 100 200 300 400 500 600 700 8008−10
7−10
6−10
5−10
Voltage [V]
Curr
ent [
A] Non-irrad.
Neutron-irrad.
IR-LED ON-OFF0 100 200 300 400 500 600 700 8008−10
7−10
6−10
5−10
Voltage [V]
Curr
ent [
A]
1.0×1015 1-MeV neq/cm2
IR-LED ON-OFF
B
CD
high
low50μm
80μm
0.3
1.0
3.0
@-20℃
Monitor Diode50D
+Charge Collection Setup
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
10
p Gain evaluation by charge collectionp Alibava: System using analog readout ASIC (Beetle) for LHCbp IR-Laser (λ=1064nm) uniformly generate h-e pairs, mimicking charged particle traversing the sensor. (spot size: 2μm×2μm)
PC�
Alibava Mother Board �
Alibava Daughter Board �
XY Stage �
HV for Sensor�
Sensor�
50 ��
Trigger Pulse 10~20 ns�
Laser
Interstrip Center
+
Charge [ADC counts]0 100 200 300 400 500 600
Even
ts /
1 co
unt
0100200300400500600700800900
1000
Non irradiated
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
11
p Gain stays constant (interstrip region)p Gain increases (center in doped region)
>50Vp Evaluation of gain:
ADC (center @V) ADC (interstrip@100V)
Charge [ADC counts]0 100 200 300 400 500 600
Even
ts /
1 co
unt
0100200300400500600700800900
1000
Center
50-200V
50V
100V 150V 200V
Interstrip
0 50 100 150 200 250 300 350 4000
5
10
15
20
25
30
35
40
Gain (V) =
Voltage [V]
Gain
@20℃
50D
50D50D
+
Charge [ADC counts]0 100 200 300 400 500 600
Even
ts /
1 co
unt
0100200300400500600700800900
1000Charge [ADC counts]
0 100 200 300 400 500 600
Even
ts /
1 co
unt
0100200300400500600700800900
1000
Gain after Proton irradiation
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
12
p 2017.02.20~ @CYRICp 1.0×1015 1-MeV neq/cm2 p After 60℃-80min. annealing
p Gain appears (interstrip)p High voltage applicable after
irradiation
p Higher voltage required to retain same gain
100V 500V 600V 650V
100V 500V
600V
650V
@20℃
Voltage [V]0 100 200 300 400 500 600 700012345678910
Gain Non-irrad.
Center
Proton-irrad.Center
interstrip
50D
50DInterstrip
Center50D
+
40− 30− 20− 10− 0 10 20 30 40012345678910
Gain Uniformity
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
13
p Non irradiatedp Uniformity dependent on bias
(require certain bias)
p After irradiationp Uniformity seems improved
- Need more study[μm]
Gain
〜〜
250V
200V
100V
40− 30− 20− 10− 0 10 20 30 40012345678910
[μm]
Gain
700V
300V
Non irradiated
After Proton irradiation3.0 ×1015 1-MeV neq/cm2
50C
50D
+Summary
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
14
p We evaluated characteristics of HPK LGAD samplesp Gain shows at ~30V (non irrad.)p Gain retains after γ-ray irradiation (2.5MGy)p After neutron irradiation, gain drops (1.0×1015 1-MeV neq/cm2 )
p We evaluated gain by charge collectionp (Interstrip) Gain appears after irradiation due to high voltage (~500V)p (Center) Gain drops after proton irradiation, needs higher voltagep Irradiation seems improve gain uniformity
p Acknowledgement
+Backup Slides
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017 15
+M.D. IV Measurements Setup
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
16
p Response to LEDs with various wavelengthp Blue (λ=464nm, D=0.5μm)p Green (λ=565nm, D=2μm)p Red (λ=627nm, D=3μm)p Infrared (λ=850nm, D=20μm)
Wavelength [nm]200 300 400 500 600 700 800 900 1000
Abso
rptio
n D
epth
[m]
9−10
8−10
7−10
6−10
5−10
4−10
3−10
+
-Voltage [V]0 100 200 300 400 500 600 700 800
Cur
rent
[A]
8−10
7−10
6−10
5−1050DPixel
Temperature Dep. of IV
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
17
p Lower temperature, higher gainp Because…
p longer mean free pathp higher acceleration energyp higher impact ionization energy
-Voltage [V]0 100 200 300 400 500 600 700 800
Cur
rent
[A]
8−10
7−10
6−10
5−1080DPixel
0℃
60℃
60℃
Monitor Diode50D 0℃
Monitor Diode80D
+CC after Proton irradiation
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
18
p 2017.02.20~ @CYRICp 1.0×1015 1-MeV neq/cm2 p After 60℃-80min. annealing
p Appear gain between stripsp P dose of bulk increase because of
bulk damage by proton irradiation
p Higher gain retain under the stripp appear at higher voltage
p Two type of electrode shapep Type A: Simplep Type B: more stable electric fieldp detail (confidential to HPK)
Charge [ADC counts]0 100 200 300 400 500 600
Even
ts /
1 co
unt
0
200
400
600
800
1000
1200
1400
Charge [ADC counts]0 100 200 300 400 500 600
Even
ts /
1 co
unt
0
200
400
600
800
1000
1200
1400 Under the strip
100V 500V
600V 700V 730V
Between strips 100V
500V
600V 700V
730V
Type B 50D
Type B 50D
@-20℃
+Non irradiated sample
Sayaka Wada HSTD11 at OIST, Japan 14 Dec. 2017
19
p Same value @low voltage(<100V)p increase C.C. under the strip @high
voltagep Evaluation of gain @each voltage:
ADC (under the strip) ADC (between the strips)
Charge [ADC counts]0 100 200 300 400 500 600
Even
ts /
1 co
unt
0500
100015002000250030003500400045005000
Charge [ADC counts]0 100 200 300 400 500 600
Even
ts /
1 co
unt
0500
100015002000250030003500400045005000
Under the strip
10-380V
10-100V
150V
200V 250V
300V 350V 380V
Between the strips
0 50 100 150 200 250 300 350 400 450 5000
5
10
15
20
25
30
35
40
Type B 50D
Gain =
Voltage [V]
Gain
Type B 50D
@20℃
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