This document discusses types of radiation, their interaction with matter, and radiation detectors. It covers the following types of radiation: photons (gamma rays and x-rays), neutrons, electrons, ions, protons, and alpha particles. It describes the processes of photoelectric effect, Compton scattering, and pair production for photon interaction, as well as scattering, capture and other interactions for neutrons. The document also discusses why radiation detection is important and gives examples of different types of radiation detectors like gas detectors, scintillation detectors, and semiconductor detectors.
1. TYPES OF RADIATION/INTERACTION
WITH MATTER/RADIATION
DETECTORS
Girish kumar Palvai
Website: www.conceptualphysicstoday.com
Email: palvaigirish@physicsdownloads.com
2. Topics under Discussion
What is Radiation?
Types of Radiation?
Interaction of radiation with matter.
Why Radiation Detection?
Types of Radiation detectors
Radiation Detectors in ECIL
Radiation --- harmful to mankind?
3. Radiation could be referred to as flux of energetic
particles emanating from Nuclei /atomic events.
The word radiation in the present world covers both high
energy photons and energetic subatomic particles such
as electrons, protons, -particles, fission products etc.
4. Process of emission of energetic
subatomic/Nuclei particles due to change
in state of certain atoms/nuclei. Such nuclei
are called unstable nuclides.
This phenomenon is called Radioactivity.
5. Types of Radiation :
1. Uncharged Radiation ( Electromagnetic Radiation )
a) Photons (Gamma Rays & X-Rays )
b) Neutrons
2. Charged Particle Radiation :
a) Light Charge Particle – eg: Beta ( electron ), Positron
3H, 14 C
b) Heavy Charged Particle – eg :Alpha : 232Th, 238 U
6.
7. Types of Radiations
Photons
Particles
Electromagnetic waves
X-rays gamma-rays Electron Ions Neutron
-ray Proton, -rays
EB
Commonly used Heavy ions
radiation sources
8. Cosmic Shower
~109-1021 eV (~ 6 GeV)
(~ km) (100mb)
2 x 1018 particles (mainly
protons) / s enter the
atmosphere
(ISOTROPIC)
Upto
~100
• Interact with atmospheric nuclei MeV
& produce secondary particles
(muons, electrons, photons,
neutrons: responsible for cosmic
dose) Flux %
H 1300 92.9
He 88 6.3
>He 10.7 1.06
9. S
o
u
r
The Neutron Sources
c
e
Cosmic radiations & High-energy particle
accelerators are well-known neutron sources
Cosmic rays: 2 types
High-Energy Particle
accelerators
13. Interaction of Gamma Photons with matter
Photoelectric effect:
The kinetic energy Ee of the
photoelectron is given by
E e= hν–E b hν
The cross section for photoelectric
absorption depends on the atomic Ee
number (Z) of the absorber and
energy of the photon Eγ
σPE α Z4.5 / Eγ3
13
14. Compton scattering
The scattered photon energy is given by
E
Esc
E
1 1 - cos
m0 c 2
The cross section for Compton scattering is hν e
θ
σ cs α Z / Eγ
hν’
14
15. Pair Production
The excess energy above 1.02 MeV is shared between the positron
and electron as kinetic energy, which are later slowed down in the
stopping medium.
Eγ= e- + e+ + Ee- + Ee+
The cross section for pair production varies with Z of the absorber
and Energy of the photon as,
σ pp α Z2 ln Eγ
15
19. Fast Neutron Interaction
In- Elastic scattering: -
Excited Compound
Nucleus
Emitted Neutron
Incident
Neutron
Gamma Ray
Target nucleus
20. Elastic scatter:
• The neutron and the nuclide collide and share a part of their kinetic
energies. They rebound with speeds different from the original speeds,
such that the total kinetic energy before and after the collision remains
the same. If the nucleus is stationary before collision, it will gain energy
from the neutron and start moving, and the neutron gets slowed down
due to loss of kinetic energy. However, the residual nucleus is not excited
but is in its ground state.
• The most important process for slowing down of neutrons.
• Total kinetic energy is conserved
• E lost by the neutron is transferred to the recoiling particle.
• Maximum energy transfer occurs with a head-on collision.
21. Non elastic scatter
• Differs from inelastic scattering in that a secondary
particle that is not a neutron is emitted after the
capture of the initial neutron.
eg: 12C ( n, α ) 9Be ; Egamma = 1.75 MeV
• Energy is transferred to the alpha particle and the
de excitation gamma ray.
22. Neutron capture
• Same as non elastic scatter, but by definition, neutron capture
occurs only at low neutron energies (thermal energy range is <
0.025 eV).
• Capture leads to the disappearance of the neutron.
• Neutron capture accounts for a significant fraction of the energy
transferred to tissue by neutrons in the low energy ranges.
eg: 1H ( n, gamma ) 2H ; Egamma = 2.2 MeV
Spallation
• In this process, after the neutron is captured, the nucleus
fragments into several parts. Only important at neutron energies in
excess on 100 MeV. (cross sections are higher at 400-500 MeV).
24. Why to detect Radiation?
• Environmental safety
• Personal protection of occupational workers
• Calibration of radioactive isotopes
• Power regulation in nuclear reactors
• Research applications
• Estimation of radiation dose in treatment of
patients and more…………….
25. How to detect Radiation?
Choose a radiation detector working on a particular
principle of interaction (ionization/scintillation/etc)
with known sensitivity to estimate the radiation under
detection.
26. Some Characteristics of Radiation Detectors
• Sensitivity
• Operating voltage
• Operating voltage region
• Radiation detection range
• Resolution (for pulse based)
• Less dead time
• Life time
27. TYPES OF RADIATION DETECTORS
Gas Flow Scintillation Semi-Conductor
Detectors Gas Filled
Detectors Detectors Radiation
Detectors
Alpha Beta Gamma Neutron Other Particles
Detectors Detectors Detectors Detectors & Energy GM
Radiation
32. GAS FILLED DETECTORS
Gamma Ion Chamber Gamma Ion Chamber B10F3 filled counter.
Criticality Alarm Systems Area Monitoring He3 filled counter.
Neutron Monitoring
Fission Detector with MI Fission Detector with MI Neutron Monitoring
cable for Source Range Self Powered Neutron Detector
cable for Intermediate
Monitoring ( BWR) Range Monitoring( BWR) Gamma Compensated neutron
Ion chamber
Uncompensated Neutron Ion
Chamber with MI cable for Power
Range Monitoring in PHWRs
35. B10 Lined Proportional Counters
Application: Used normally for physical or
normal start-up of Reactors.
Sensitivity From 0.8 to 20 CPS/nV
4 CPS/nV detectors are supplied regularly to
NPCIL for Reactor Start-up
Enriched Boron (96% enriched amorphous fine
powder) is the main constituent.
10B + 0n1 (5B11) (3Li7 )+++ + (2He4 )++ + 2.34 Mev
36. B10 Coated Ion chambers
Supplied regularly to NPCIL for Reactor Power
Measurement in Intermediate and Power Range
Sensitivity:
Neutron: 10-14 Amps/nv,
Gamma: 10-11 Amps/R/hr (Un Compensated)
10-12 Amps/R/hr (Compensated)
37. B10 coated Ion chamber with integral MI cable assembly
Boron-10 coated chamber with integral MI cable assembly
Neutron Sensitivity: 1x10-14 Amps/nv
Gamma Sensitivity: 2.5 x10-12 Amps/R/h
Range: 104 to 1011 nv
Operating Voltage: 600 V
Operating Temperature: 100 deg C
Dimensions: 88 mm dia, 330 mm length,
38. 10BF Gas Filled Detectors
3
Sensitivity from 4 to 150 CPS/nv
25 CPS/nv detectors are supplied regularly to NPCIL,
BARC for DNM and other systems
Enriched Boron Complex (B10 F3 CaF2 ).. 90% enriched
powder) is the main conversion material to generate
BF3 Gas by thermal decomposition.
B10 F3 CaF2 complex currently produced by HWB
Generation and purification system is made by ECIL
39. He3 Detectors
Sensitivity from 10 to 250 CPS/nv
Applications: SNM detection
systems, research applications etc.
Supplied to IGCAR, BARC for Neutron well
counters and other applications
40.
41. Fission Detectors
• HEU based
SRM, IRM, LPRM, Wide Range
Sensitivity From 10-3 to 1 CPS/nv, With & Without
integral MI Cable
Supplied to BWR, FBTR
• LEU (<20% Enrichment) based
Sensitivity From 10-3 to 0.18 CPS/nv, With & Without
integral MI Cable
Supplied to BARC, PHWR
High Temperature (650o C) Fission Counter for PFBR
42. FD for Source Range Monitor
Used for incore flux monitoring in BWRs.
Pulse mode operation
U-235 (90% enriched) coated counter with integral MI cable assembly
Sensitivity: 10-3 CPS/nv
Range: 104 to 109 nv
Operating Voltage: 350 V
Operating Temperature: 300 deg C
Dimensions: 6 mm dia, 75 mm length, sensitive length: 25 mm
43. Local Power Range Monitor
U-235 (90% enriched) coated chamber with integral MI cable assembly
Neutron Sensitivity: 1x10-17 Amps/nv
Range: 1011 to 1013 nv
Gamma Sensitivity: Less than 5x10-14 Amps/R/h
Operating Voltage: 100 V
Operating Temperature: 300 deg C
Dimensions: 6 mm dia, 75 mm length, sensitive length: 25 mm
44. Self Powered Neutron Detectors
Sensitivity: 10-22 Amps/nv
Operating temperature: Up to 3000C
Emitter: Cobalt, Vanadium, Platinum
Supplied regularly to NPCIL for Incore Flux Mapping
Fabricated with Integral MI Cable
Tested for hydrostatic pressure of 250 kg/cm2
47. Gamma Detectors
Gamma Ion Chambers
• CRITICALITY-CAS-G11;
• AREA MONITORING-G12, 12A;
• ISOTOPE CALIBRATION- well type-G13;
• ENVIRONMENTAL RADIATION MONITORING-G15,
G17
• FUEL FAILURE DETECTION, DHRUVA , BARC-G20,
G21
48. • Application: Criticality Alarm System
• Gamma Field range: 1mR/hr to 1000R/hr
• Sensitivity : 3 x 10-10 A/R/Hr
• Fill gas: Nitrogen + Argon
• Seismic qualified
49. • Application: Shut Down Area Range Monitor
• Gamma Field range: 1mR/hr to 1000R/hr
• Sensitivity : 4.5 x 10-9 A/R/Hr
• Fill gas: Nitrogen + Argon
• Seismic qualified
50. • Application: Wide Range Gamma Monitor
• Gamma Field range: 100 mR/hr to 104 R/hr
• Sensitivity : 1.0 x 10-10 A/R/Hr
• Fill gas: Nitrogen + Argon
• Seismic qualified
51. GAMMA IONISATION CHAMBER #G12 & #G12A for SHUTDOWN
AREA RADIATION MONITOR &
WIDE RANGE GAMMA RADIATION MONITOR for PHWR
APPLICATIONS