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Radioactive Decay
Too many
proto
ns
Too many
neutr
ons
Too big
7/13/09 10:25 AMDecay Radiation Results
Page 2 of 3file:///Users/david/Documents/Clinical/Teaching/Nuclear%20Medicine%…Teaching/Types%20of%20decay/Tc99%20Decay%20Radiation%20Results.htm
XR k!1 21.657 8.54E-5 % 24 1.85E-8 5
XR k!2 22.074 2.00E-5 % 6 4.42E-9 13
89.6 3 S 0.0010 % 9.3E-7
232.8 2 8.5E-6 % 20 2.0E-8 5
322.4 2 9.7E-5 % 17 3.1E-7 5
Dataset #2:
Authors: J. K. TULI, G. REED, B. SINGH Citation: Nuclear Data Sheets 93, 1 (2001)
Parent Nucleus
Parent E(level)
Parent J"
Parent T1/2
Decay Mode GS-GS Q-value
(keV)Daughter Nucleus
Decay
Scheme 99
43Tc 142.6832 11 1/2- 6.015 h 9 IT: 99.9963 6 %
99
43Tc
Electrons:
Energy (keV)
Intensity (%)
Dose ( MeV/Bq-s )
CE M 1.6286 11 74.595 % 0.0012149
Auger L 2.17 10.32 % 6 2.240E-4 14
Auger K 15.5 2.05 % 4 3.17E-4 6
CE K 119.4670 12 8.84 % 0.01056
CE K 121.59 3 0.55 % 5 6.7E-4 6
CE L 137.4685 11 1.07 % 0.00147
CE L 139.59 3 0.172 % 16 2.40E-4 23
CE M 139.9670 14 0.194 % 2.72E-4
CE NP 140.4430 22 0.0374 % 5.25310E-5
CE M 142.09 3 0.034 % 3 4.8E-5 5
CE NP 142.56 3 0.0066 % 6 9.4E-6 9
Gamma and X-ray radiation:
Energy (keV)
Intensity (%)
Dose ( MeV/Bq-s )
2.1726 4 6.201E-9 % 1.347E-13
XR l 2.42 0.447 % 11 1.08E-5 3
XR k#2 18.251 2.14 % 6 3.91E-4 11
XR k#1 18.367 4.07 % 12 7.47E-4 21
XR k!3 20.599 0.330 % 10 6.79E-5 20
XR k!1 20.619 0.639 % 18 1.32E-4 4
XR k!2 21.005 0.145 % 4 3.04E-5 8
140.511 1 89.06 % 0.1251
142.63 3 0.0187 % 18 2.7E-5 3
Dataset #3:
Author: L. K. PEKER Citation: Nuclear Data Sheets 73,1 (1994)
Parent Nucleus
Parent E(level)
Parent J"
Parent T1/2
Decay Mode GS-GS Q-value
(keV)Daughter Nucleus
A conversion electron is ejected by a gamma photon from the nucleus
A conversion electron is ejected by a gamma photon from the nucleus
A kα X-ray comes when an electron from the L shell falls to
the K shell
A kα X-ray comes when an electron from the L shell falls to
the K shell
An Auger electron is ejected by a kα X-ray
An Auger electron is ejected by a kα X-ray
Gamma decay comes when nucleus falls from high energy state to low energy stateGamma rays can be absorbed by electrons in the atomConversion electron: Gamma ray ejects electronk-α, L-β X-ray radiation when electrons from high shells fall to low shellsAuger electrons when k-α absorbed by outer electrons, ejecting them.
Gamma decay comes when nucleus falls from high energy state to low energy stateGamma rays can be absorbed by electrons in the atomConversion electron: Gamma ray ejects electronk-α, L-β X-ray radiation when electrons from high shells fall to low shellsAuger electrons when k-α absorbed by outer electrons, ejecting them.
Alpha decay energy
400
1200
800
1600
Energy, MeV
!235
!247
!286
!280
!330
!334
!342
!350
!376 !174!124
!80!30
!61!0
5.70 5.905.80 6.00
Num
ber
of part
icle
s
short
standard
long
37480 Tipler(Freem) LEFT INTERACTIVE
top of RHbase of RH
top of txtbase of txtMoreMore
Energetics of Alpha Decay
The energy released in ! decay, Q, is determined by the difference in mass of theparent nucleus and the decay products, which include the daughter nucleus and the! particle. Consider the decay of 232Th (Z ! 90) into 228Ra (Z ! 88) plus an ! particle.This is written as
232 228 228 4Th !: Ra " ! (! Ra " He) 11-33
The energy Q is usually expressed in terms of atomic masses (which include themasses of the electrons) because, as explained earlier, these are the masses measuredin mass spectroscopy. If MP is the mass of the parent atom, MD that of the daughteratom, and MHe that of the helium atom, the decay energy Q is given by conservationof mass energy as
Q! M # (M " M ) 11-34P D He2c
Note that the mass of the two electrons in the He atom compensates for the factthat the daughter atom has two fewer electrons than the parent atom. Applying thisto 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 4.002603u 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 232This 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 energyof the daughter nucleus. If the parent nucleus is at rest when it decays, the daughter
Fig. 11-19 Alpha-particlespectrum from 227Th. Thehighest-energy ! particlescorrespond to decay to theground state of 223Ra with atransition energy of Q ! 6.04MeV. The next highest energyparticles, !30, result fromtransitions to the first excitedstate of 223Ra, 30 keV abovethe ground state. The energylevels of the daughter nucleus,223Ra, can be determined bymeasurement of the !-particleenergies.
Continued
Gamma decay comes when nucleus falls from high energy state to low energy stateGamma rays can be absorbed by electrons in the atomConversion electron: Gamma ray ejects electronk-α, L-β X-ray radiation when electrons from high shells fall to low shellsAuger electrons when k-α absorbed by outer electrons, ejecting them.
Alpha decay when nucleus is too largeAlpha particles emitted at specific energiesNot dangerous from outside: can’t penetrate skinDangerous when ingested/inhaled
Gamma decay comes when nucleus falls from high energy state to low energy stateGamma rays can be absorbed by electrons in the atomConversion electron: Gamma ray ejects electronk-α, L-β X-ray radiation when electrons from high shells fall to low shellsAuger electrons when k-α absorbed by outer electrons, ejecting them.
Alpha decay when nucleus is too largeAlpha particles emitted at specific energiesNot dangerous from outside: can’t penetrate skinDangerous when ingested/inhaled
p+ β-
νn
n ⇨ p + e– + ν_
p ⇨ n + e+ + νp + e– ⇨ n + ν
7/10/09 10:53 AMDecay Radiation Results
Page 2 of 4file:///Users/david/Documents/Clinical/Teaching/Nuclear%20Medicine%…0Teaching/Types%20of%20decay/Y90%20Decay%20Radiation%20Results.htm
XR k!1 16.738 0.581 % 21 9.7E-5 3
XR k!2 17.013 0.111 % 4 1.90E-5 7
202.53 3 97.3 % 4 0.1970 7
479.51 5 90.74 % 5 0.43510 24
681.8 6 0.32 % 3 0.00217 19
Dataset #2:
Author: E. BROWNE Citation: Nuclear Data Sheets 82, 379 (1997)
Parent Nucleus
Parent E(level)
Parent J"
Parent T1/2
Decay Mode GS-GS Q-value
(keV)Daughter Nucleus
DecayScheme 90
39Y 682.04 2 7+ 3.19 h 1 !- 2280.1 16
9040
Zr
Beta-:
Energy (keV)
End-point energy (keV)
Intensity (%)
Dose ( MeV/Bq-s )
232.5 10 643.2 16 0.0018 % 3 4.2E-6 7
Mean beta- energy: 2.3E+2 keV 5, total beta- intensity: 0.0018 % 3, mean beta- dose: 4.2E-6 MeV/Bq-s 11
Gamma and X-ray radiation:
Energy (keV)
Intensity (%)
Dose ( MeV/Bq-s )
2318.968 10 0.00180 % 4.2E-5
Dataset #3:
Author: E. BROWNE Citation: Nuclear Data Sheets 82, 379 (1997)
Parent Parent Parent Parent T1/2
Decay Mode GS-GS Q-value Daughter
7/10/09 11:04 AMDecay Radiation Results
Page 3 of 4file:///Users/david/Documents/Clinical/Teaching/Nuclear%20Medicine%…0Teaching/Types%20of%20decay/Y90%20Decay%20Radiation%20Results.htm
Gamma and X-ray radiation:
Energy
(keV)
Intensity
(%)
Dose
( MeV/Bq-s )
2318.968 10 0.00180 % 4.2E-5
Dataset #3:
Author: E. BROWNE Citation: Nuclear Data Sheets 82, 379 (1997)
Parent
Nucleus
Parent
E(level)
Parent
J!
Parent
T1/2Decay Mode
GS-GS Q-value
(keV)
Daughter
Nucleus
Decay
Scheme 90
39Y 0 2- 64.00 h 21 "-: 100 % 2280.1 16
90
40Zr
Beta-:
Energy
(keV)
End-point energy
(keV)
Intensity
(%)
Dose
( MeV/Bq-s )
25.0 7 93.8 16 1.4E-6 % 3 3.5E-10 8
185.6 10 519.4 16 0.0115 % 14 2.1E-5 3
933.7 12 2280.1 16 99.9885 % 14 0.9336 12
Mean beta- energy: 933.6 keV 12, total beta- intensity: 100.0000 % 20, mean beta- dose:
0.9336 MeV/Bq-s 12
Electrons:
Energy Intensity Dose
Decay radiation
p
n
e+
νe
u u
u d d
d
W+
–+
Positron decay makes back-to-back photons
TOTALEnergy: 2mc2 = 1022 keVCharge: 0Momentum: 0
–+
–+
Positron decay makes back-to-back photons
TOTALEnergy: 2mc2 = 1022 keVCharge: 0Momentum: 0
Energy: hν
= 511 keV
Charge: 0
Momentum: h/λ = +511
Energy: hν
= 511 keV
Charge: 0
Momentum: h/λ = -511
7/13/09 8:45 AMDecay Radiation Results
Page 1 of 1file:///Users/david/Documents/Clinical/Teaching/Nuclear%20Medicine%…0Teaching/Types%20of%20decay/F18%20Decay%20Radiation%20Results.htm
Search parameters:
Nucleus:18F
Results:
Dataset #1:
Authors: TILLEY, WELLER, CHEVES, CHASTELER Citation: Nuclear Physics A595, 1 (1995)
Parent
Nucleus
Parent
E(level)
Parent
J!
Parent
T1/2Decay Mode
GS-GS Q-value
(keV)
Daughter
Nucleus
Decay
Scheme 18
9F 0 1+ 109.77 m 5 "+: 100 % 1655.50 63
18
8O
Beta+:
Energy
(keV)
End-point energy
(keV)
Intensity
(%)
Dose
( MeV/Bq-s )
249.8 3 633.5 6 96.73 % 4 0.2416 3
Mean beta+ energy: 249.8 keV 3, total beta+ intensity: 96.73 % 4, mean beta+ dose: 0.2416 MeV/Bq-s 3
Electrons:
Energy
(keV)
Intensity
(%)
Dose
( MeV/Bq-s )
Auger K 0.52 3.072 % 11 1.597E-5 6
Gamma and X-ray radiation:
Energy
(keV)
Intensity
(%)
Dose
( MeV/Bq-s )
XR k#2 0.525 0.009 % 3 4.5E-8 18
XR k#1 0.525 0.017 % 7 9E-8 4
Annihil. 511.0 193.46 % 8
p+ β-
νn
p ⇨ n + e+ + νp + e– ⇨ n + νmp+me+Q = mn+Eout
mp+Q = mn+me+Eout
Positron decay requires enough initial energy to make a positron
7/13/09 10:45 AMDecay Radiation Results
Page 1 of 2file:///Users/david/Documents/Clinical/Teaching/Nuclear%20Medicine%…Teaching/Types%20of%20decay/C057%20Decay%20Radiation%20Results.htm
Search parameters:
Nucleus:57CO
Results:
Dataset #1:
Author: M. R. BHAT Citation: Nuclear Data Sheets 85, 415 (1998)
Parent
Nucleus
Parent
E(level)
Parent
J!
Parent
T1/2Decay Mode
GS-GS Q-value
(keV)
Daughter
Nucleus
Decay
Scheme 57
27Co 0.0 7/2- 271.74 d 6 ": 100 % 836.0 4
57
26Fe
Electrons:
Energy
(keV)
Intensity
(%)
Dose
( MeV/Bq-s )
Auger L 0.67 251 % 4 0.001684 24
Auger K 5.62 105.1 % 17 0.00591 10
CE K 7.3009 11 71.1 % 24 0.00519 18
CE L 13.5668 7 7.4 % 3 1.00E-3 3
CE K 114.9487 9 1.83 % 10 0.00211 12
CE L 121.2146 4 0.192 % 17 2.32E-4 21
CE K 129.3616 9 1.30 % 14 0.00169 18
Gamma and X-ray radiation:
Energy
(keV)
Intensity
(%)
Dose
( MeV/Bq-s )
XR l 0.7 1.52 % 15 1.06E-5 11
XR k#2 6.391 16.6 % 9 0.00106 5
XR k#1 6.404 32.9 % 15 0.00211 10
XR k$1 7.058 3.91 % 19 2.76E-4 13
XR k$3 7.058 2.00 % 10 1.41E-4 7
14.4129 6 9.16 % 15 0.001320 22
122.06065 12 85.60 % 17 0.10448 21
136.47356 29 10.68 % 8 0.01458 11
230.4 4 4E-4 % 4 9E-7 9
339.69 21 0.0037 % 3 1.26E-5 10
352.33 21 0.0030 % 3 1.06E-5 11
Gamma decay comes when nucleus falls from high energy state to low energy stateGamma rays can be absorbed by electrons in the atomConversion electron: Gamma ray ejects electronk-α, L-β X-ray radiation when electrons from high shells fall to low shellsAuger electrons when k-α absorbed by outer electrons, ejecting them.
Alpha decay when nucleus is too largeAlpha particles emitted at specific energiesNot dangerous from outside: can’t penetrate skinDangerous when ingested/inhaled
Beta decay: neutron turned into proton or proton turned into neutronNeutrino takes some energy: beta particle has range of energiesPositron decay makes annihilation photonsElectron capture: nucleus grabs low-lying electron
Gamma decay comes when nucleus falls from high energy state to low energy stateGamma rays can be absorbed by electrons in the atomConversion electron: Gamma ray ejects electronk-α, L-β X-ray radiation when electrons from high shells fall to low shellsAuger electrons when k-α absorbed by outer electrons, ejecting them.
Alpha decay when nucleus is too largeAlpha particles emitted at specific energiesNot dangerous from outside: can’t penetrate skinDangerous when ingested/inhaled
Beta decay: neutron turned into proton or proton turned into neutronNeutrino takes some energy: beta particle has range of energiesPositron decay makes annihilation photonsElectron capture: nucleus grabs low-lying electron