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Radionuclide Dosimetric Data Sheets
Cesium-138
Summary data
General
Classification
Isotope: Cs-138
Atomic number (Z): 55
Mass number (A): 138
Neutron number (N): 83
Radioactive decay
Decay modes: β-
Half-life: 33.41 [m]
Decay constant: 3.4578e-04 [1/s]
Daughters: Ba-138 (100.0%)
Radioactive daughters: None
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 1.24621 [MeV]
Mean photon energy: 2.36111 [MeV]
Air kerma rate constant, Γ10: 7.738e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 7.738e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.997e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δα: 0.000e+00
[Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δβ-,β+,e-:
1.997e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 3.783e-13
[Gy·kg/Bq·s]
Dose point kernels (plot)
Dose point kernel source: Graves, et al. Medical Physics. 2019 Nov.; 46(11):5284-5293.
Note: Bins are spaced every 0.1 mm until a radius of 10 cm, and every 1 mm until a radius of 2 m.
Download tabulated dose point kernel file here: www.mirdsoft.org/products/MIRDspecs/Cs-138 DPK.csv
Summary spectra (plot)
Spectra source: ICRP Publication 107: Nuclear Decay Data for Dosimetric Calculations. Ann. ICRP 2008, 38 (3).
Download tabulated summary spectra file here: www.mirdsoft.org/products/MIRDspecs/Cs-138 Summary Spectrum.csv
Beta spectra (plot)
Spectra source: ICRP Publication 107: Nuclear Decay Data for Dosimetric Calculations. Ann. ICRP 2008, 38 (3).
Download tabulated beta spectra file here: www.mirdsoft.org/products/MIRDspecs/Cs-138 Beta Spectrum.csv
Tabulated data
Summary spectra (table)
Spectra source: ICRP Publication 107: Nuclear Decay Data for Dosimetric Calculations. Ann. ICRP 2008, 38 (3).
Note: Radiations with yield < 0.01 are excluded from the table, but are available in the linked *.csv data.
Download tabulated summary spectra file here: www.mirdsoft.org/products/MIRDspecs/Cs-138 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
1.86005e-05 |
2.642e-01 |
X-ray |
|
1.38100e-01 |
1.488e-02 |
Gamma |
|
2.27760e-01 |
1.511e-02 |
Gamma |
|
4.08980e-01 |
4.662e-02 |
Gamma |
|
4.62796e-01 |
3.075e-01 |
Gamma |
|
5.47001e-01 |
1.076e-01 |
Gamma |
|
8.71800e-01 |
5.112e-02 |
Gamma |
|
1.00978e+00 |
2.983e-01 |
Gamma |
|
1.14722e+00 |
1.244e-02 |
Gamma |
|
1.34359e+00 |
1.145e-02 |
Gamma |
|
1.43586e+00 |
7.630e-01 |
Gamma |
|
2.21800e+00 |
1.518e-01 |
Gamma |
|
2.63959e+00 |
7.630e-02 |
Gamma |
|
1.04672e+00 |
1.591e-02 |
Beta |
|
1.11101e+00 |
8.808e-02 |
Beta |
|
1.12518e+00 |
1.672e-02 |
Beta |
|
1.20043e+00 |
4.404e-01 |
Beta |
|
1.26431e+00 |
7.307e-02 |
Beta |
|
1.30589e+00 |
1.301e-01 |
Beta |
|
1.45431e+00 |
1.371e-01 |
Beta |
|
1.67031e+00 |
4.304e-02 |
Beta |
|
1.08630e-05 |
5.637e-02 |
Auger electron |
|
4.69638e-05 |
3.265e-02 |
Auger electron |
|
4.88068e-05 |
8.943e-02 |
Auger electron |
|
1.14550e-04 |
1.286e-02 |
Auger electron |
|
5.52135e-04 |
2.928e-02 |
Auger electron |
|
3.56752e-03 |
1.149e-02 |
Auger electron |
Useful Links
Isotope decay characteristics are periodically updated as better measurements can be made - changes that may not be reflected on this page. Please see useful links:
National Nuclear Data Center (NNDC): https://www.nndc.bnl.gov/nudat3/mird/
International Atomic Energy Agency (IAEA) Livechart: https://www-nds.iaea.org/relnsd/vcharthtml/VChartHTML.html
Reference Links
ICRP Report 107: https://www.icrp.org/publication.asp?id=ICRP%20Publication%20107
Graves et al. Dose Point Kernels: https://doi.org/10.1002/mp.13789
MIRD Decay Schemes 2nd Edition: https://sites.snmmi.org/SNMMI-MAIN/iCore/Store/StoreLayouts/Item_Detail.aspx?iProductCode=0-932004-80-6
MIRDsoft MIRDspecs version 20250101 (www.mirdsoft.org)
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