Types of radioactive decay

Radioactive Decay

Too many

proto

ns

Too many

neutr

ons

Too big

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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

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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

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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

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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

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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