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The Nature of
Radiation
January 10, 2001

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Learning Objectives
Know basic constituents of the atom
Define and give an examples of:
Isotopes
Nuclides
Radionuclides
Ra...
Learning Objectives
List charged and uncharged particles
Write the equation that describes how
uncharged particles are att...
Basic Nuclear Particles
Atom: consists of protons,
neutrons & electrons
Proton, mass = 1.007277 amu
Neutron, mass = 1.0086...
Basic Nuclear Particles
Beta ( -), mass = 0.000549 amu
Positron ( +), mass = 0.000549 amu
Alpha (), mass = ~4 amu

Gamm...
b er
num
ass N
M +
=Z

A
Z

Nuclear Terms

XN

At
nu om
m ic
be
r

ron
t
eu ber
N m
nu

Nucleons
Protons and neutrons

Nuc...
b er
num
ass N
M +
=Z

A
Z

Nuclear Terms,
continued

XN

At
nu om
m ic
be
r

ron
t
eu ber
N m
nu

Radionuclide
Radioactiv...
Classification of Nuclear Particles

ged
r
ha
C

art
P

s
cle
i

alpha (), + 2 charge
Proton, +1 charge
Electron, -1 char...
Classification of Nuclear Particles

nc
U

ar
h

le s
tic
ar
dP
ge

Neutron

Gamma ray

X ray

Jump to first page
Charged Particle Interactions
alpha ()

e-

e-

e-

e-

e-

ionization
e-

e-

e-

e-

beta ( -)

e-

ionization

ee

e-...
Uncharged Particle Interactions
photons

eeee-

recoil nuclei

fast neutron
recoil nuclei

thermal neutron

diffusion

rec...
Important Radiation
Interactions in Matter
Production of Bremsstrahlung
Photon Interactions
Photoelectric Effect
Compton E...
Bremsstrahlung
Radiation
Electrons are
deflected and
accelerated in the
Coulomb field of
the nucleus.

e-

Accelerated
ele...
Photon Interactions Photoelectric Effect

eJump to first page
Photon Interactions Compton Effect

eJump to first page
Photon Interactions –
Pair Production

e+

e-

Jump to first page
Photon Interactions –
Positron Annihilation

e+
e-

e-

e+
Jump to first page
Important Equations
Alpha Particle Range
Beta Particle Range
Proton Range
Photon Absorption
Neutron Absorption

Jump to fi...
Alpha Particle Range

Rα = 0.318 E

3/ 2

Where:
Rα =

range in cm of air at 1
atm and 15oC
E =
energy in MeV

Note…this i...
pes
: Ty s
bar tion
ide ua
S eq Dimensionally correct
of
Internally consistent
May be physics based
May include empiricall...
pes
: Ty s
bar tion
ide ua
S eq
Empirically derived
f
o
Experimental method of science
applied to the creation of equation...
Beta Particle Range

Rβ = 412 E

1.265 − 0.0954 ln E

For particles 0.01<E<2.5 MeV
Where
Rβ =

range expressed in mg/cm2

...
Proton Range
1.8

Rp

 E 
=

 9 .3 
Where
Rp =
E =

range expressed in
meters of air
energy in MeV (few MeV to 200
M...
The “one-size fits all”
equation
N = N0e

−λ t

Activity decay equation

I = I0e

−µ x

Atom decay equation

A = A0 e

−λ ...
I=

Photon Absorption
− µx
I 0e
Where
I0 is the original exposure rate or beam
fluence or flux
I is the attenuated exopsur...
Neutron Absorption

I = I 0e

−σNx

Where

= I 0e

− Σx

I0 is the original neutron intensity
I is the attenuated neutron ...
Behavior of Exponential Functions
Linear plot
N0

Semi-log plot
ln (N0)

N

ln N
t, x, or Z

t, x, or Z

Jump to first pag...
The Chart of the Nuclides
Still available
See Jean Robinson, NE Office

A portable resource
Known elements
Stable and radi...
Chart of the Nuclides

Jump to first page
Chart Information

Jump to first page
Chart Information, cont’d

Jump to first page
Chart Information,
cont’d

Jump to first page
Chart Information,
cont’d

Jump to first page
Summary
Basic constituents of the atom
Defined and give an examples of
nuclear terms
Described major radiation
interaction...
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Lecture 1-The Nature of Radiation

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Lecture 1-The Nature of Radiation

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Transcript of "Lecture 1-The Nature of Radiation"

  1. 1. The Nature of Radiation January 10, 2001 Jump to first page
  2. 2. Learning Objectives Know basic constituents of the atom Define and give an examples of: Isotopes Nuclides Radionuclides Radioisotopes Radiations Know major radiation interactions in matter Become familiar with and use equations to describe radiation interactions Jump to first page
  3. 3. Learning Objectives List charged and uncharged particles Write the equation that describes how uncharged particles are attenuated Describe/draw an image of how uncharged particles penetrate into matter Calculate the: Range of an alpha particle in air Range of a beta particle in a known material Attenuation of a photon beam Attenuation of a neutron beam Jump to first page
  4. 4. Basic Nuclear Particles Atom: consists of protons, neutrons & electrons Proton, mass = 1.007277 amu Neutron, mass = 1.008665 amu Electron, mass = 0.000549 amu Jump to first page
  5. 5. Basic Nuclear Particles Beta ( -), mass = 0.000549 amu Positron ( +), mass = 0.000549 amu Alpha (), mass = ~4 amu Gamma ray, no mass X ray, no mass Jump to first page
  6. 6. b er num ass N M + =Z A Z Nuclear Terms XN At nu om m ic be r ron t eu ber N m nu Nucleons Protons and neutrons Nuclide Species of atom defined by Z and A 1 H, 238U, 2H are all nuclides Isotopes Nuclides of same element (Z), different number of neutrons (N) 1 H, 2H, 3H are isotopes of H Isotones Nuclides with same number of neutrons 206 Pb and 204Hg Jump to first page
  7. 7. b er num ass N M + =Z A Z Nuclear Terms, continued XN At nu om m ic be r ron t eu ber N m nu Radionuclide Radioactive nuclide Radioisotope Radioactive isotope Radiation Particles or waves with sufficient energy to interact with or cause ionization of the atoms with which they interact Jump to first page
  8. 8. Classification of Nuclear Particles ged r ha C art P s cle i alpha (), + 2 charge Proton, +1 charge Electron, -1 charge beta ( -), -1 charge positron ( +), + 1 charge Jump to first page
  9. 9. Classification of Nuclear Particles nc U ar h le s tic ar dP ge Neutron Gamma ray X ray Jump to first page
  10. 10. Charged Particle Interactions alpha () e- e- e- e- e- ionization e- e- e- e- beta ( -) e- ionization ee e- e- positron ( ) Ionization and annihilation radiation e- - + ee - e- e- annihilation radiation 0.511 MeV ee- e - e- e+ annihilation radiation 0.511 MeV Jump to first page
  11. 11. Uncharged Particle Interactions photons eeee- recoil nuclei fast neutron recoil nuclei thermal neutron diffusion recoil nuclei elastic scattering of nuclei and production of recoil nuclei photon Absorption with (n,) reaction Jump to first page
  12. 12. Important Radiation Interactions in Matter Production of Bremsstrahlung Photon Interactions Photoelectric Effect Compton Effect Pair Production Positron Annihilation Jump to first page
  13. 13. Bremsstrahlung Radiation Electrons are deflected and accelerated in the Coulomb field of the nucleus. e- Accelerated electric charges emit electromagnetic waves (X-rays) e- e- Jump to first page
  14. 14. Photon Interactions Photoelectric Effect eJump to first page
  15. 15. Photon Interactions Compton Effect eJump to first page
  16. 16. Photon Interactions – Pair Production e+ e- Jump to first page
  17. 17. Photon Interactions – Positron Annihilation e+ e- e- e+ Jump to first page
  18. 18. Important Equations Alpha Particle Range Beta Particle Range Proton Range Photon Absorption Neutron Absorption Jump to first page
  19. 19. Alpha Particle Range Rα = 0.318 E 3/ 2 Where: Rα = range in cm of air at 1 atm and 15oC E = energy in MeV Note…this is an empirically derived equation, the units don’t “work out” Jump to first page
  20. 20. pes : Ty s bar tion ide ua S eq Dimensionally correct of Internally consistent May be physics based May include empirically derived Example: Velocity (m/s) = distance (m) / time (t) Units “work out” Examples Radiation attenuation equations Radioactive decay Jump to first page
  21. 21. pes : Ty s bar tion ide ua S eq Empirically derived f o Experimental method of science applied to the creation of equations. Hypotheses generated to test theory Data collected and analyzed. Patterns extracted to describe observed behavior Units may not “work out” Examples Many “rules of thumb” Range equations Jump to first page
  22. 22. Beta Particle Range Rβ = 412 E 1.265 − 0.0954 ln E For particles 0.01<E<2.5 MeV Where Rβ = range expressed in mg/cm2 E = maximum energy in MeV Note…this is also an empirically derived equation, the units don’t “work out” Jump to first page
  23. 23. Proton Range 1.8 Rp  E  =   9 .3  Where Rp = E = range expressed in meters of air energy in MeV (few MeV to 200 MeV) Note…this is also an empirically derived equation, the units don’t “work out” Jump to first page
  24. 24. The “one-size fits all” equation N = N0e −λ t Activity decay equation I = I0e −µ x Atom decay equation A = A0 e −λ t Photon attenuation equation And many more…. Jump to first page
  25. 25. I= Photon Absorption − µx I 0e Where I0 is the original exposure rate or beam fluence or flux I is the attenuated exopsure rate, fluence or flux µ is the linear absorption coefficeint (cm-1) x is the thickness of the absorber e is the base of the natural logarithm (2.718..) Jump to first page
  26. 26. Neutron Absorption I = I 0e −σNx Where = I 0e − Σx I0 is the original neutron intensity I is the attenuated neutron intensity N is the number of atoms per cm3 in the absorbing material σ is the cross section of the abosrber (capture coefficient (cm2) x is the thickness of the absorber (cm) e is the base of the natural logarithm (2.718..) Σ is the macroscopic cross section of the absorber Jump to first page
  27. 27. Behavior of Exponential Functions Linear plot N0 Semi-log plot ln (N0) N ln N t, x, or Z t, x, or Z Jump to first page
  28. 28. The Chart of the Nuclides Still available See Jean Robinson, NE Office A portable resource Known elements Stable and radioactive forms Periodic table Brief description of nuclear properties Conversion tables! Jump to first page
  29. 29. Chart of the Nuclides Jump to first page
  30. 30. Chart Information Jump to first page
  31. 31. Chart Information, cont’d Jump to first page
  32. 32. Chart Information, cont’d Jump to first page
  33. 33. Chart Information, cont’d Jump to first page
  34. 34. Summary Basic constituents of the atom Defined and give an examples of nuclear terms Described major radiation interactions in matter Listed equations to describe radiation interactions Layout of the Chart of the Nuclides Jump to first page
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