<= Return to MIRDspec isotope database


Radionuclide Dosimetric Data Sheets

Cesium-127

Summary data

General

Classification

Isotope:  Cs-127
Atomic number (Z):  55
Mass number (A):  127
Neutron number (N):  72

Radioactive decay

Decay modes:  β+, Electron capture
Half-life:  6.25 [h]
Decay constant:  3.0807e-05 [1/s]
Daughters:  Xe-127 (100.0%)
Radioactive daughters:  Xe-127

Dosimetric constants

Mean alpha energy:  0.0 [MeV]
Mean electron energy:  0.02934 [MeV]
Mean photon energy:  0.43336 [MeV]
Air kerma rate constant, Γ10:  1.858e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair:  1.976e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or electrons), Δwp:  4.701e-15 [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-:  4.701e-15 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp:  6.943e-14 [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-127 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-127 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-127 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-127 Summary Spectrum.csv

 

Energy [MeV]

Yield [#/nt] if > 0.01

Radiation type

1.66177e-05

1.234e+01

X-ray

4.09719e-03

3.942e-02

X-ray

4.41300e-03

2.287e-02

X-ray

2.94521e-02

2.271e-01

X-ray

2.97812e-02

4.206e-01

X-ray

3.35665e-02

3.948e-02

X-ray

3.36295e-02

7.655e-02

X-ray

3.44080e-02

1.615e-02

X-ray

1.24700e-01

1.137e-01

Gamma

2.87160e-01

3.825e-02

Gamma

3.21540e-01

1.306e-02

Gamma

4.11950e-01

6.280e-01

Gamma

4.62310e-01

5.074e-02

Gamma

5.11000e-01

6.108e-02

Annihilation photon

5.87010e-01

4.208e-02

Gamma

2.96288e-01

1.314e-02

Positron

4.76761e-01

1.264e-02

Positron

2.61927e-05

1.924e+00

Auger electron

3.62444e-05

5.866e+00

Auger electron

1.23738e-04

7.241e-01

Auger electron

3.22357e-04

1.396e-01

Auger electron

5.05191e-04

1.606e+00

Auger electron

6.17505e-04

9.195e-02

Auger electron

3.32576e-03

6.330e-01

Auger electron

4.00312e-03

1.878e-01

Auger electron

4.70752e-03

1.427e-02

Auger electron

2.44715e-02

6.385e-02

Auger electron

2.86854e-02

2.857e-02

Auger electron

9.01440e-02

4.411e-02

Conversion electron

3.77394e-01

1.001e-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)

<= Return to MIRDspec isotope database