From my class on nuclear physics for nuclear medicine technologists. This class covers alpha, beta, and gamma decay, plus conversion electrons, Auger electrons, and k-alpha and other X-rays
16. Gamma decay comes when nucleus falls
from high energy state to low energy state
Gamma rays can be absorbed by electrons
in the atom
Conversion electron: Gamma ray ejects
electron
k-α, L-β X-ray radiation when electrons
from high shells fall to low shells
Auger electrons when k-α absorbed by
outer electrons, ejecting them.
17. Gamma decay comes when nucleus falls
from high energy state to low energy state
Gamma rays can be absorbed by electrons
in the atom
Conversion electron: Gamma ray ejects
electron
k-α, L-β X-ray radiation when electrons
from high shells fall to low shells
Auger electrons when k-α absorbed by
outer electrons, ejecting them.
20. MP (MD MHe ) 11-34
c2
Note that the mass of the two electrons in the He atom compensates for the fact
that the daughter atom has two fewer electrons than the parent atom. Applying this
to the example given in Equation 11-33, the mass of the 232Th atom is 232.038124 u
The mass of the daughter atom 228Ra is 228.031139 u, and adding it to the 4.002603
u mass of 4He, we get 232.033742 u for the total mass of the decay products
Equation 11-34 then yields Q/c 2 0.004382 u, which, when multiplied by the con-
version factor 931.5 MeV/c 2, gives Q 4.08 MeV. Thus, the rest energy of 232Th
is greater than that of 228Ra 4He; therefore, 232Th is unstable toward spontaneous
decay.
The kinetic energy of the particle (for decays to the ground state of the daugh-
ter nucleus) is slightly less than the decay energy Q because of the small recoil energy
of the daughter nucleus. If the parent nucleus is at rest when it decays, the daughter
1600
!286
Number of particles
1200 !61
!0
800
!334
!330
400 !
!376 342 !247 !174 !80
!350 !30
!280 !235 !124
5.70 5.80 5.90 6.00
Energy, MeV
21.
22.
23. Alpha decay when nucleus is too large
Alpha particles emitted at specific energies
Not dangerous from outside: can’t penetrate
skin
Dangerous when ingested/inhaled
Gamma decay comes when nucleus falls
from high energy state to low energy state
Gamma rays can be absorbed by electrons
in the atom
Conversion electron: Gamma ray ejects
electron
k-α, L-β X-ray radiation when electrons
from high shells fall to low shells
Auger electrons when k-α absorbed by
outer electrons, ejecting them.
24. Alpha decay when nucleus is too large
Alpha particles emitted at specific energies
Not dangerous from outside: can’t penetrate
skin
Dangerous when ingested/inhaled
Gamma decay comes when nucleus falls
from high energy state to low energy state
Gamma rays can be absorbed by electrons
in the atom
Conversion electron: Gamma ray ejects
electron
k-α, L-β X-ray radiation when electrons
from high shells fall to low shells
Auger electrons when k-α absorbed by
outer electrons, ejecting them.
25.
26. _
n p + e– + ν
p n + e+ + ν
p + e– n+ ν
n ν
p+ β-
39. Positron decay makes
back-to-back photons
1 keV
= 51 11
hν +5
1k
eV
– g y: : 0
er ge h/λ
=
51 En ar m:
: hν
= 511 h entu
gy : 0
er ge λ=
- + C m
Mo
n r
E a : h/
Ch men tum
Mo TOTAL
Energy: 2mc2 = 1022 keV
Charge: 0
Momentum: 0
47. Alpha decay when nucleus is too large
Alpha particles emitted at specific energies
Not dangerous from outside: can’t penetrate
skin
Dangerous when ingested/inhaled
Beta decay: neutron turned into proton or
proton turned into neutron
Neutrino takes some energy: beta particle
has range of energies
Positron decay makes annihilation photons
Electron capture: nucleus grabs low-lying
electron
Gamma decay comes when nucleus falls
from high energy state to low energy state
Gamma rays can be absorbed by electrons
in the atom
Conversion electron: Gamma ray ejects
electron
k-α, L-β X-ray radiation when electrons
from high shells fall to low shells
Auger electrons when k-α absorbed by
outer electrons, ejecting them.
48. Alpha decay when nucleus is too large
Alpha particles emitted at specific energies
Not dangerous from outside: can’t penetrate
skin
Dangerous when ingested/inhaled
Beta decay: neutron turned into proton or
proton turned into neutron
Neutrino takes some energy: beta particle
has range of energies
Positron decay makes annihilation photons
Electron capture: nucleus grabs low-lying
electron
Gamma decay comes when nucleus falls
from high energy state to low energy state
Gamma rays can be absorbed by electrons
in the atom
Conversion electron: Gamma ray ejects
electron
k-α, L-β X-ray radiation when electrons
from high shells fall to low shells
Auger electrons when k-α absorbed by
outer electrons, ejecting them.