<= Return to MIRDspec isotope database

Radionuclide Dosimetric Data Sheets

Cesium-137

Isotope:  Cs-137
Atomic number (Z):  55
Mass number (A):  137
Neutron number (N):  82

Decay modes:  β-
Half-life:  30.17 [y]
Decay constant:  7.2811e-10 [1/s]
Daughters:  Ba-137m (94.4%), Ba-137 (5.6%)
Radioactive daughters:  Ba-137m

Mean alpha energy:  0.0 [MeV]
Mean electron energy:  0.18836 [MeV]
Mean photon energy:  0.0 [MeV]
Air kerma rate constant, Γ₁₀:  6.108e-23 [Gy·m²/Bq·s]
Air kerma coefficient, K_air:  6.108e-23 [Gy·m²/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or electrons), Δ_wp:  3.018e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δ_α:  0.000e+00 [Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δ_β-,β+,e-:  3.018e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δ_p:  0.000e+00 [Gy·kg/Bq·s]

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-137 DPK.csv

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-137 Summary Spectrum.csv

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-137 Beta Spectrum.csv

 

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-137 Summary Spectrum.csv

 

Energy [MeV]	Yield [#/nt] if > 0.01	Radiation type
1.74293e-01	9.440e-01	Beta
4.25616e-01	5.600e-02	Beta

 

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

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)

<= Return to MIRDspec isotope database