Introduction to Silicon Detectors J. Lee Center for High Energy Physics Kyungpook National University First School for Particle Detectors and Applications @ SPDAK 2019 2019. 1. 14
Introduction to Silicon Detectors
J. LeeCenter for High Energy PhysicsKyungpook National University
First School for Particle Detectors and Applications @ SPDAK 2019
2019. 1. 14
Outline
1. Introduction
โข Types of silicon detectors
โข Interaction of particles with silicon
2. Properties of silicon
3. Silicon detectors for charged particle detection
4. Silicon detectors for photon detection
5. Summary
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1. Introduction
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Types of Silicon Detectors
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Pixel sensor for CMShttp://hep.fi.infn.it/CMS/sensors/Silicon_Detector.gif
Double-side strip sensor
Single-side strip sensor
Strip-pixel sensor
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Interaction of charged particles with silicon
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By S. Banerjee & A. Caner
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Energy loss by ionization
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3.6 eV required for producing a pair of e-h in Siโ 10,000 e-h pairs / 100 ฮผm expected in Si
Bethe equation
z: charge of incident particle
<๐๐ธ
๐๐ฅ> โ 40 keV / 100 ฮผm in Si for minimum ionizing particles
<๐๐ธ
๐๐ฅ> โ z2
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Photon energy (eV)
Interaction of photons with silicon
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Photon energy (keV)
Photon energy (eV)
(A)
(B)
(C)
Comptonscattering
Photoelectric effect Pair production
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References for the plots in Page 6
A. Sze, S. M., Physics of Semiconductor Devices, John Wiley and Sons, N.Y., 1981. Jellison, Jr., G. E. and F. A. Modine, Appl. Phys. Lett- 41, 2 (1982) 180-182.
B. X-RAY DATA BOOKLET, Lawrence Berkeley National Laboratory
C. Durini (Editor), โHigh Performance Silicon Imaging: Fundamentals and Applications of CMOS and CCD Sensorsโ, Woodhead Publishing, 2014 Particularly: Chapter 10 (p286) by R. Turchetta, STFC, UK
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2. Properties of silicon
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Band & bandgap
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From โSemiconductor Devices
Physics and Technology Second Editionโ
by S.M. Sze
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Indirect vs Direct Bandgap Semiconductors
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Direct bandgap Indirect bandgap
phonon
Si GaAs
Excitation/De-excitation = EgExcitation/De-excitation = Eg + Ephonon
From โSemiconductor DevicesPhysics and Technology Second Editionโ by S.M. Sze
SPDAK 2019
โข abundant --> cheap
โข Lighter
โข SiO2 layer
โ Naturally or inexpensively formed
โ chemically and mechanically very stable
โ effectively passivates the surface states of the underlying silicon
โ forms an effective diffusion barrier for the commonly used dopant species
โ easily preferentially etched from the silicon, and vice versa, with high selectivity
โ By contrast, GeO2 is a chemically unstable, poor electrical insulator that is 33 times more soluble in water than SiO2, making it less suited to the photolithographic and wet chemical processes used to fabricate integrated circuits.
Why Silicon?
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Sand to silicon wafer
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Recipe for fabrication process
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Clean wafer
Oxidation
Cover with
photoresist
Expose
through mask
Develop
Etch SiO2
N+Diffusion
P+ Implantation
Anneal
Metallization
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Intrinsic Si semiconductor
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low T : electrons bound in lattice higher T : free electrons & holes
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The crystalline structure is Diamond Cubic (FCC).Bare wafers of or crystals are popular onesused for silicon detector fabrications.
Impurities
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Jargons
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Doping: acceptors & donors
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Effect of doping
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3. Silicon detectors for charged particle detection
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p-n junction (fundamental structure)
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The depletion region d is a region with no charge carriers (with nofree charges).
dSPDAK 2019
p-n junction
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Depletion depth
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d=
d=
d=
d=
d=
AD N and N of smallest the is NB
field barrier to due difference potential : Vbi
An exercise :
intrinsic Si at 300K
V~110 V
d~300 ฮผm
cm 5103.3
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p-n junction reverse bias characteristics
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0
0
VV for const.
VV for
C
VC /1
0
0
VV for
VV for
0dd
Vd
thickness junctiond
voltage depletion fullV
0
0
depth layer depletiond
0
0
VV for const.
VV for
i
Vdi
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PIN Diode
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Intrinsic or lightly doped
n p
pn
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When a charged particle traverses the depletion zone
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~ 10,000 e-h pairs / 100 ฮผm
Intrinsic or lightly doped
Simple detector
n p
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Silicon pixel sensor
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โข PIN diode, DC typeโข Wafer: 5 inch, 525 ฮผm in thickness, double polished side,
N-type high resistivity (>5 kโฆ-cm), (111) orientation
Measure the ionization energy loss in silicon sensor-> Determine the charge of the incident particle
P+ (0.6 ฮผm)
N+ (1.0 ฮผm)
currentHigh Energy Charged Particle,
or Nuclei
Intrinsic โ N-type high resistivity bias voltage
Al
SiO2
<๐๐ธ
๐๐ฅ> โ z2
pixel size = 1.55 cm x 1.38 cm
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Silicon Pixel Sensor & Ladder for SCD
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pixel size = 1.55 x 1.38 cm2
Built by SKKU group
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Silicon Charge Detector (design, fabrication & assembly
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Built by SKKU group
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Silicon Charge Detector (specification)
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ISS-CREAM payload
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BSD
Instrument
BCD
Instrument
TCD
Instrument
Calorimeter
PIU
Electronics
Rack (1 of 3)
Grapple Fixture
(1 of 2)
Calorimeter
Composite Base
Plate
Targets
HPDs
(2 of 4)
Power
Distribution
Boxes
ATCS
BSD
Electronics
Readout Box
Fluid Loop
Accumulators Not Shown (Located behind Power Distribution Boxes
- Housekeeping Box
- Science Flight Computers
Vents
(1 of 2)
4-layer SCD (built by SKKU group)
Mass ~ 1258 kgPower ~ 415 WLength ~ 185 cm
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ISS-CREAM @ GSFC before TVAC test (July 22-25, 2015)
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ISS-CREAM in space operation
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SCD performance: standalone tracking
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ฮธ = 34.19 +1.91 -0.59ยฐ
ฯ = 105.5 +5.9 -2.9ยฐ
layer1
layer2
layer3
layer4
4
A 4-layer track!
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SCD performance: charge measurement
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Preliminary!
C
N
O
NeMg Si
S
Fe
z
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ATLAS Silicon Trackers
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4. Silicon detectors for photon detection
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MOS structure (fundamental structure)
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CCD (Charge Coupled Device) sensor
Charge Coupled Device
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Photoelectrons produced by photoelectric
effect
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CCD analogy
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output = charge
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CCD inventors (winners of Nobel prize in physics in 2010)
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Having Fun @ Bell Lab in 1974 !
G. E. Smith & W.S. Boyle : invented CCD in 1970
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How much advanced?
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Kodak Mega pixel CCD~ 1cm2
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CCD application in Astronomy/Astrophysics
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CMOS sensor
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PD = Photo Diode output = voltage
CMOS : Complementary Metal Oxide Semiconductor
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A pixel in CMOS sensor
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Layout of typical CMOS sensor
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CCD & CMOS summary
์์น์ ์ผ๋ก๋ ๋์ผ, ์ฆ ํฌํ ๋ค์ด์ค๋ ๊ตฌ์กฐ๋ก, ๊ด์ ์ธ๊ธฐ๊ฐ ์ ํ๋์ผ๋ก ๋ณํ๋๊ณ , ์ ํ๋ฅผ ์ ์์ผ๋ก ๋ณํ ์ถ๋ ฅ
๋ณํ๊ธฐ๊ฐ ์ด๋์ ์์นํ๋๊ฐ๊ฐ ๋ ์ผ์์ ๊ทผ๋ณธ์ ์ธ ์ฐจ์ดโ ํฝ์ ์ ์ ๋ณด ์ด๋ ๋ฐฉ๋ฒ์ ์ฐจ์ด, ์ฆ CCD๋ ์ ํ๋ก ํฝ์ ๊ฐ ์ด๋ ์ต์ข ์ ์์ผ
๋ก ๋ณํ, CMOS๋ ํฝ์ ๋จ์์์ ์ ์์ผ๋ก ๋ณํํ์ฌ ์ด๋
์ก์์ด ํฌ๊ณ , ๋์ ํญ (dynamic range) ๋ฐ ์๋์์ ๋ฐ์ด๋์ง ์์โ ๋์ ํญ = Full Well Capacity / ์ก์โ Kodak Mega ํฝ์ CCD 200,000 ์ ์ / 20์ ์ = 100,000
๊ด๋์ด ์ ์ ํ๊ฒฝ์์๋ ๊ณ ๋ฏผ๊ฐ๋์ ์ผ์๊ฐ ํ์ํ๋, CCD์ CMOS๋์ฆํญํ ์ผ์๊ฐ ์๋๋ฏ๋ก ์ผ๊ฐ ์ํฉ์์ ๊ทธ ์ฑ๋ฅ์ ํ๊ณ
์ฐ๋ฆฌ์ ๋์ ๋ฏผ๊ฐ๋๋ CCD ๋ณด๋ค ์ฐ์ํจโ CCD ๋ฏผ๊ฐ๋ ~ 0.03 Lux (๋๊ฐ ์ 0.002 Lux)
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Photomultiplier
โข ์ ํํ ๋งํ๋ฉด ๊ด์ ์๋ฅผ ๋ค์์ ์ ์๋ก ์ฆํญ
โข ๊ด์๊ทน(photocathode)๊ณผ ํจ๊ป ์ฌ์ฉํ๋ PMT(Photomultiplier Tube) ์ MCP(Microchannel Plate)๊ฐ ๋ํ์ ์ผ๋ก๋จ์ผ ๊ด์ ๊ณ์ ๊ฐ๋ฅ
โข ๋ฐ๋์ฒด ์์์์๋ ์ผ์ ๋ด๋ถ์์๊ด์ ์(photoelectron)๋ฅผ์ฆํญ: ICCD(Intensified CCD), EB(Electron Bombardment)CCD, EM(Electron Multiplier)CCD, APD(Avalanche Photodiode), SiPM(Silicon Photomultiplier)
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Photomultiplier Tubes (PMTs)
โข ์ด๋ฏผ๊ฐ ์ด๊ณ ์ ํน์ฑ์ ๊ฐ๋ ๊ด์ผ์๋ก ๊ณผ๊ฑฐ ์์ญ๋ ๊ฐ ํน์๋ชฉ์ ์ ์ฌ์ฉ
โข ๊ทธ๋ฌ๋ ์ง๊ณต๊ด์์ผ๋ก ๋ถํผ๊ฐ ๋งค์ฐ ํฌ๊ณ , ์ถฉ๊ฒฉ์ ์ทจ์ฝํ๋ฉฐ ๊ณ ์ ์์ํ์๋ก ํ๋ฏ๋ก, ์ผ์ ์์ ๋ด๊ตฌ์ฑ, ํด๋์ฑ ๋ฐ ์ค์ฉ์ฑ์ด ํฌ๊ฒ ๋จ์ด์ง๋ฉฐ, ๊ด๋์ด ๋ง์์ง๋ฉด ์์๊ฐ ํ๊ดด๋๋๋ฌธ์
PMT์ ์๋ฆฌ์ Hamamatsu์ฌ ์ ํ
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20 inch World largest PMT
For Super-K
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SiPM (Silicon PhotoMultiplier)
โข Micropixel (Geiger mode APD) ์ด๋ ์ด๋ก ์ด๋ฃจ์ด์ง ๋ฐ๋์ฒด ๊ด๋ค์ด์ค๋
โข Micropixel์ ํฌ๊ธฐ๋ 10~100ฮผm๋ก 1mm2์ ๋ฉด์ ๋น 100~1000๊ฐ ์ง์
โข ๊ฐ Micropixel ์ ๊ณตํต์ ์ธ๊ฐ์ ์๊ณผ ๋ก๋ ์ ํญ์ผ๋ก ์๋, ์ถ๋ ฅ์ ํธ๋ ๋ชจ๋ Micropixel ์ ํธ์ ํฉ(multiplexed output)
โข ์ฆ Binary์ ๋์งํธ์์๋ก ์ ์ฌ๊ด์ ์๋ฅผ ์ธ๋ ์๋ ๋ก๊ทธ์์ ๊ด์ผ์
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Geiger Mode
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SiPM
โข PN ์ ํฉ๋ฉด์๋งค์ฐ ๋์ ์ ๊ธฐ์ฅ ํ์ฑ
โข ํ ๊ฐ์ ๊ด์ ์ ์ฌ -> 100๋ง ๋ฐฐ์ ์ ์์ฆํญ๋ฐ์ -> ์ด ๋ฏผ ๊ฐ ๋ !!
โข ๊ด์ด ์ ์ฌ๋์์ ๋ ์ผ์์ ๋ฐ์ ์๋ -> 1ns ์ด ๊ณ ์ ๋ !!
21
N+
P+
Electric field
10
6
10
2
10
40
E (V
/cm)
X (u
m)
34
56
SiPM์ Micropixel2019-01-14 SPDAK 2019
Analog Signal
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Q(t)
Analog Signal & Dynamic/Working Range
IRST of INFN Pisa
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SiPM ํฝ์ : 1 x 1 mm2 ํฌ๊ธฐ(30x30ฮผm2ํฌ๊ธฐ, 103๊ฐ์๋ง์ดํฌ๋กํฝ์ )
64ch SiPM ์์ : 1 x 1 cm2
๋คํ์์ฉ 8 x 8 ํฝ์ ์ด๋ ์ด ์์
1cm
1cm
1
1
64ch ์ค๊ณ๋
64ch SiPM ์ผ์(1cm2)์ ํ๋ฏธ๊ฒฝ ์ฌ์ง
1cm
1cm
1 2 3 4 5 6 7 8
2
3
4
5
6
7
8
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1024 ํ์ ๋ฐฐ์ด
1024 ํ์ ๊ตฌ์ฑ
๋จ์์์= 8x8 ํ์
1024 ํ์= 4x4 ๋จ์์์
ํ์
1mm x 1mm
8mm x 8mm
32mm x 32mm
30ฮผm
30ฮผm
32x32 = 1024 mircro-pixels
in parallel
a micro-pixel
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๋จ์์์ 4๊ฐ๊ฐ wirebonding๋ Rigid-FPCB
์ ์๋ SiPM ๋จ์ ์์๋ค (๊ฐ 1cm2, 64ch์ ํฝ์ ๋ก ๊ตฌ์ฑ)
SiPM ํฝ์ 1024ch ์ ์: 1 x 1 mm2 ํฌ๊ธฐ(30x30ฮผm2ํฌ๊ธฐ, 103๊ฐ์๋ง์ดํฌ๋กํฝ์ )
64ch SiPM ์์ : 1 x 1 cm2
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16๊ฐ์ 8 x 8 SiPM ํฝ์ ์ด๋ ์ด๋ก ๊ตฌ์ฑ๋ ๋คํ์ (1024-ch)
ํญ๋ณต์ ์ ๊ท ์ผ->
Multi channel test
4cm
4cm
1๋จ๊ณ SiPM ํฝ์ 1024ch ์ ์: 1 x 1 mm2 ํฌ๊ธฐ(30x30ฮผm2ํฌ๊ธฐ, 103๊ฐ์๋ง์ดํฌ๋กํฝ์ )
64ch SiPM ์์ : 1 x 1 cm2
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1024-ch
Voltage(V)
1024-ch SiPM + ์ ํธ์ฒ๋ฆฌ์ฅ์น + Pinhole
Pinhole
Electronics
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Image Test
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SiPM Pinhole
10 cm
10 cm
A
APinhole Camera
Image TestPinhole Camera
200 cm
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Absolutely Dark!CCD or CMOS camerascan NOT get this image!
SiPM Applications
โข ์ฒ์ฒด/์ฒ๋ฌธ: ๋ฏธ์ฝํ ๊ด์ ํธ ์ธก์ ์ ์ํ ๊ด์ผ์
โข ๋ณด์ ๊ฐ์ : Homeland Security
โข ์๋ฃ์ฉ : PET Scanners, Medical imaging
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5. Summary
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Summary
โข Silicon is one of most popular material for radiation detection in the fields of Particle physics/Astro-particle physics
โ Charged particle detection
โ Photon detection
โข During Lab, try to understand
โ C-V & I-V characteristics of silicon detectors
โ Responses (signals) of silicon detector to radiation sources or cosmic muons)
โข Signal as a function of Vbias ?
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Back-up slides
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dE/dx is of random nature
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Probabilitydensity Function~ LandauFunction
0
sin)](lnexp[/1)( uuudufL
Landau functionMost probable dE/dx
Due to ฮด rays:Knock-on electrons
From Review of Particle Physics
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Absorption Coefficient
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