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Radionuclide Dosimetric Data Sheets

Cesium-135m

Isotope:  Cs-135m
Atomic number (Z):  55
Mass number (A):  135
Neutron number (N):  80

Decay modes:  Internal transition
Half-life:  53.0 [m]
Decay constant:  2.1797e-04 [1/s]
Daughters:  Cs-135 (100.0%)
Radioactive daughters:  Cs-135

Mean alpha energy:  0.0 [MeV]
Mean electron energy:  0.03606 [MeV]
Mean photon energy:  1.59723 [MeV]
Air kerma rate constant, Γ₁₀:  5.882e-17 [Gy·m²/Bq·s]
Air kerma coefficient, K_air:  5.882e-17 [Gy·m²/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or electrons), Δ_wp:  5.777e-15 [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-:  5.777e-15 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δ_p:  2.559e-13 [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-135m 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-135m Summary 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-135m Summary Spectrum.csv

 

Energy [MeV]	Yield [#/nt] if > 0.01	Radiation type
2.18869e-05	5.093e-01	X-ray
3.09789e-02	1.742e-02	X-ray
7.87200e-01	9.970e-01	Gamma
8.46100e-01	9.589e-01	Gamma
2.09394e-05	6.789e-02	Auger electron
4.14435e-05	2.417e-01	Auger electron
1.19589e-04	2.974e-02	Auger electron
5.28337e-04	6.641e-02	Auger electron
3.44715e-03	2.612e-02	Auger electron
8.10115e-01	3.410e-02	Conversion electron

 

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

 

 

 

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