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Radionuclide Dosimetric Data Sheets
Cesium-123
Summary data
General
Classification
Isotope: Cs-123
Atomic number (Z): 55
Mass number (A): 123
Neutron number (N): 68
Radioactive decay
Decay modes: β+, Electron capture
Half-life: 5.88 [m]
Decay constant: 1.9647e-03 [1/s]
Daughters: Xe-123 (100.0%)
Radioactive daughters: Xe-123
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.95089 [MeV]
Mean photon energy: 1.08595 [MeV]
Air kerma rate constant, Γ10: 1.523e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 4.258e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.523e-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-:
1.523e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 1.740e-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-123 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-123 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-123 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-123 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
1.66176e-05 |
7.246e+00 |
X-ray |
|
4.09719e-03 |
2.324e-02 |
X-ray |
|
4.41300e-03 |
1.358e-02 |
X-ray |
|
2.94521e-02 |
1.331e-01 |
X-ray |
|
2.97812e-02 |
2.464e-01 |
X-ray |
|
3.35665e-02 |
2.313e-02 |
X-ray |
|
3.36295e-02 |
4.485e-02 |
X-ray |
|
7.12600e-02 |
1.242e-02 |
Gamma |
|
8.33800e-02 |
4.086e-02 |
Gamma |
|
9.73900e-02 |
2.270e-01 |
Gamma |
|
2.61800e-01 |
2.157e-02 |
Gamma |
|
3.07100e-01 |
3.859e-02 |
Gamma |
|
4.34300e-01 |
1.067e-02 |
Gamma |
|
4.99200e-01 |
1.407e-02 |
Gamma |
|
5.11000e-01 |
1.413e+00 |
Annihilation photon |
|
5.13600e-01 |
1.589e-02 |
Gamma |
|
5.96600e-01 |
1.010e-01 |
Gamma |
|
6.11100e-01 |
3.178e-02 |
Gamma |
|
6.44200e-01 |
2.270e-02 |
Gamma |
|
6.67800e-01 |
1.022e-02 |
Gamma |
|
6.93700e-01 |
1.294e-02 |
Gamma |
|
7.41500e-01 |
2.951e-02 |
Gamma |
|
1.17620e+00 |
2.043e-02 |
Gamma |
|
1.27320e+00 |
3.178e-02 |
Gamma |
|
8.57434e-01 |
2.242e-02 |
Positron |
|
1.05137e+00 |
1.560e-02 |
Positron |
|
1.10045e+00 |
3.607e-02 |
Positron |
|
1.16057e+00 |
3.217e-02 |
Positron |
|
1.16724e+00 |
7.993e-02 |
Positron |
|
1.23844e+00 |
2.047e-02 |
Positron |
|
1.34905e+00 |
1.657e-02 |
Positron |
|
1.36331e+00 |
4.581e-02 |
Positron |
|
1.39887e+00 |
1.755e-01 |
Positron |
|
1.44432e+00 |
2.144e-01 |
Positron |
|
2.61724e-05 |
1.129e+00 |
Auger electron |
|
3.62407e-05 |
3.447e+00 |
Auger electron |
|
1.23765e-04 |
4.244e-01 |
Auger electron |
|
3.20379e-04 |
8.046e-02 |
Auger electron |
|
5.05115e-04 |
9.451e-01 |
Auger electron |
|
6.17295e-04 |
5.408e-02 |
Auger electron |
|
3.32489e-03 |
3.725e-01 |
Auger electron |
|
4.00209e-03 |
1.105e-01 |
Auger electron |
|
2.44715e-02 |
3.741e-02 |
Auger electron |
|
2.86854e-02 |
1.674e-02 |
Auger electron |
|
3.67040e-02 |
2.364e-02 |
Conversion electron |
|
4.88240e-02 |
5.015e-02 |
Conversion electron |
|
6.28340e-02 |
1.798e-01 |
Conversion electron |
|
9.19731e-02 |
2.162e-02 |
Conversion 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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