![Page 1: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/1.jpg)
Space Instrumentation
![Page 2: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/2.jpg)
Definition
![Page 3: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/3.jpg)
How do we measure these particles?
h
p+e-
Device Signal
Source
![Page 4: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/4.jpg)
Short History
![Page 5: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/5.jpg)
![Page 6: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/6.jpg)
Early Imaging Device (Image Intensifier)
photocathode
photoelectron
………….........
Light
1000V
0V
Fluorescence screen
Lens
Signal processing
![Page 7: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/7.jpg)
Early Image Intensifiers
![Page 8: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/8.jpg)
Early Image Intensifier (cont’d)
![Page 9: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/9.jpg)
Major Discovery
![Page 10: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/10.jpg)
Dynodes
![Page 11: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/11.jpg)
Continuous Electron Multiplier (CEM)
![Page 12: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/12.jpg)
Detector (Modern)
![Page 13: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/13.jpg)
Modern Image Intensifier
![Page 14: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/14.jpg)
Principles of Detectors
![Page 15: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/15.jpg)
Coulomb Interaction (Classical)
• During “collision”, moves very little, so electric field can be calculated (Not valid if V ~ ve).
• Calculate momentum acquired by electron, e-.
• Impulse acquired by the electron = (electrostatic force) (time of collision)
o
b
me
zeV
€
Δp= F∫ dt = F⊥∫ dt = ze2
b2
⎛
⎝
⎜ ⎜ ⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟ ⎟ ⎟
bV
⎛
⎝
⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟
Ion
Electron
![Page 16: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/16.jpg)
Coulomb Interaction (Cont’d)
• As charged particles lose energy by electromagnetic interactions, electrons of the matter are raised to excited energy states.
- If to continuum, electron ionized (otherwise electrons excited)
• The rate of energy loss per unit of path length by ions
z = charge of the particle, n= number of e- /cm3, b = impact parameter. €
dEdx ⎛
⎝
⎜ ⎜
⎞
⎠
⎟ ⎟ions
= 4πz2e4nmv2
⎛
⎝
⎜ ⎜
⎞
⎠
⎟ ⎟lnbmax
bmin
⎛
⎝
⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟
![Page 17: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/17.jpg)
Energy loss of charged particles (Ions)
• Energy loss of heavy charged particle through matter is (H. Bethe)
where v and ze are velocity and charge of the primary particle, I is average ionization potential of the absorber (detector), and N and Z are the number density and atomic number of the absorber.
• For v << c, only first term in bracket significant.
• Equation valid for different types of charged particles if v >> vorbital of
electrons in absorber.• For v << c, dE/dx varies as 1/v2.
• Energy transfer maximum when charged particles have low energy and spends more time in the vicinity of electron in the matter.
• z2 dependence means particles with high z have larger energy loss
(dE/dx for He++ > p+).
€
dEdx
=−4πNZz2e4
mov2 ln2mov2
I−ln1−v2
c2
⎛
⎝
⎜ ⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟ ⎟−v2
c2
⎡
⎣
⎢ ⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥ ⎥
![Page 18: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/18.jpg)
Energy loss of meson in Cu
![Page 19: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/19.jpg)
Energy loss of Ions through air
![Page 20: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/20.jpg)
Range of ions
€
R= dEdx ⎛
⎝
⎜ ⎜
⎞
⎠
⎟ ⎟Eo
0∫
−1
dE
Si
![Page 21: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/21.jpg)
![Page 22: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/22.jpg)
€
dEdx
=−2πNZe4
mov2 ln mov2E2I 2(1−β 2)
−ln2(2 1−β 2 −1+β 2
⎡
⎣
⎢ ⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥ ⎥
+(1−β 2)+18
(1− 1−β 2 )2)
€
dEdx
=−NEZ(Z+1)e4
137mo2c4
4ln 2Em
oc2
−43
⎡
⎣
⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥
![Page 23: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/23.jpg)
Range of Electrons
€
R= dEdx ⎛
⎝
⎜ ⎜
⎞
⎠
⎟ ⎟Eo
0∫
−1
dE
backscatter straggle
![Page 24: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/24.jpg)
Range of Electrons• Range similar in different material
![Page 25: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/25.jpg)
Electron Backscattering
• When an electron hits an atom it can undergo a very large angle deflection, (can often scatter out of the material).
• Larger Z has more backscattering.
![Page 26: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/26.jpg)
Electron Energy Loss by Radiation (Bremsstrahlung)
• Radiation loss (Bethe)
€
dEdx
⎛
⎝
⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟=−NEZ(Z+1)e4
137mo2c4
4ln 2Em
oc2
− 43
⎛
⎝
⎜ ⎜ ⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟ ⎟ ⎟
• Presence of E and Z2 in the numerator indicates radiation losses important for high energy electrons and for material of high atomic number Z.
• For monoenergy electron, bremsstrahlung X-ray spectrum is continuous and extends to as high as the electron energy.
• Shown is 5.3 MeV electron on Au-W target
![Page 27: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/27.jpg)
Energy loss electrons (Cont’d)• Total Loss
• Ratio
where E is in MeV and Z is the atomic number of the absorber.
• For Silicon, for example. Z~14. Radiation loss ~Collision loss when E ~ 50 MeV. For Pb, Z=82, so E ~8.5 MeV.
€
dEdx
⎛
⎝
⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟= dE
dx
⎛
⎝
⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟c
+ dEdx
⎛
⎝
⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟r
€
dEdx
⎛
⎝
⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟T
=
dEdx
⎛ ⎝ ⎜
⎞ ⎠ ⎟r
dEdx
⎛ ⎝ ⎜
⎞ ⎠ ⎟
c
≈ EZ700 Useful Formula
![Page 28: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/28.jpg)
Photon interaction with Matter
![Page 29: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/29.jpg)
Photon interaction with matter• Photoelectric effect: the photon kicks loose an electron. The energy of the electron is the incident photon energy minus the binding energy.
• Compton effect: the photon hits an electron and some of the energy is transferred but the photon keeps going.
• Pair production: the incident photon interaction in the matter creates electron positron pair.
• Each of these processes produces electrons (positrons) interacting with scintillators (matter) that emit photons (uv-visible) characteristic of the scintillator that the PMTs can “see.”
![Page 30: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/30.jpg)
Photon Interaction-1
€
E=hν −Eb
€
σ=k× Z n
(hν )3.5
![Page 31: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/31.jpg)
Photon Interaction-2
€
hν '= hν1+ hν
moc2 (1−cosθ)
![Page 32: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/32.jpg)
Photon Interaction-3
€
E−+E
+=hν −m
oc2
![Page 33: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/33.jpg)
Absorption coefficient in Si
![Page 34: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/34.jpg)
Design a photon Instrument
• Designing an X- and -ray instrument requires taking into account all three interaction processes.
• For example, if the goal is to measure of X-ray energy spectra,
one needs to reduce Compton effect.
• Compton scattering degrades energy spectra.
• Here, x must be thick enough to capture the photon with good efficiency but thin enough to minimize the Compton interaction.
€
I = Ioe−(μ ph+μc+μ pp)x
![Page 35: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/35.jpg)
Simulation Tools
![Page 36: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/36.jpg)
Ion Simulation Software
![Page 37: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/37.jpg)
CASINO Simulation
![Page 38: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/38.jpg)
Protons in Silicon
dE/dx
![Page 39: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/39.jpg)
Alpha particles in Silicon
![Page 40: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/40.jpg)
CASINO -" monteCArloSImulationof electroNtrajectory in sOlids".
![Page 41: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/41.jpg)
CASINO Simulation result in Si
![Page 42: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/42.jpg)
Electrons in Silicon
![Page 43: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/43.jpg)
The End
![Page 44: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/44.jpg)
€
dEdx
=−2πNZe4
mov2 ln mov2E2I 2(1−β 2)
−ln2(2 1−β 2 −1+β 2
⎡
⎣
⎢ ⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥ ⎥
+(1−β 2)+18
(1− 1−β 2 )2)
€
dEdx
=−4πNZz2e4
mov2 ln2mov2
I−ln1−v2
c2
⎛
⎝
⎜ ⎜ ⎜ ⎜
⎞
⎠
⎟ ⎟ ⎟ ⎟−v2
c2
⎡
⎣
⎢ ⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥ ⎥
![Page 45: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/45.jpg)
Empirical Formula for Energy loss
• Feather’s rule (electron)
R = 0.542E – 0.133 for E >0.8 MeV
in Al, but OK for other substance. R in gm/cm2, E in MeV.
For example, R~2 MeV/gm/cm2; 1 cm plastic scintillator will stop 2 MeV particles .
• Wilson’s formula (R. R. Wilson, 1951)
R = ln 2[1+E/(Ec ln2)]
Ec= 700/(Z+1.2) MeV defined as that energy at which the ionizatio loss = radiation energy loss.
![Page 46: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/46.jpg)
Design a photon Instrument
€
I = Ioe−(μ ph+μc+μ pp)x
• Designing an X-ray instrument requires taking into account all three interaction processes. • For example, if the goal is to measure of X-ray energy spectra, must reduce Compton effect.• Compton scattering degrades energy spectra.
• Here, x must be thick enough to capture the photon with good efficiency but thin enough to minimize the Compton interaction.
![Page 47: Space Instrumentation. Definition How do we measure these particles? h p+p+ e-e- Device Signal Source](https://reader030.vdocument.in/reader030/viewer/2022032612/56649eac5503460f94bb2492/html5/thumbnails/47.jpg)
TRIM/SRIM Ion Simulation