<= Return to MIRDspec isotope database
Radionuclide Dosimetric Data Sheets
Tellurium-121m
Summary data
General
Classification
Isotope: Te-121m
Atomic number (Z): 52
Mass number (A): 121
Neutron number (N): 69
Radioactive decay
Decay modes: Electron capture, Internal transition
Half-life: 154.0 [d]
Decay constant: 5.2094e-08 [1/s]
Daughters: Te-121 (88.6%), Sb-121 (11.4%)
Radioactive daughters: Te-121
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.08167 [MeV]
Mean photon energy: 0.21759 [MeV]
Air kerma rate constant, Γ10: 1.066e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 1.066e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.309e-14 [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-:
1.309e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 3.486e-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/Te-121m 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/Te-121m Summary 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/Te-121m Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
1.22327e-05 |
2.907e+00 |
X-ray |
|
1.36125e-05 |
1.190e+01 |
X-ray |
|
3.75695e-03 |
3.371e-02 |
X-ray |
|
4.02446e-03 |
1.253e-02 |
X-ray |
|
2.60930e-02 |
4.673e-02 |
X-ray |
|
2.63486e-02 |
8.721e-02 |
X-ray |
|
2.71868e-02 |
1.028e-01 |
X-ray |
|
2.74652e-02 |
1.914e-01 |
X-ray |
|
2.97173e-02 |
1.543e-02 |
X-ray |
|
3.09378e-02 |
1.762e-02 |
X-ray |
|
3.09901e-02 |
3.417e-02 |
X-ray |
|
2.12189e-01 |
8.142e-01 |
Gamma |
|
1.10215e+00 |
2.538e-02 |
Gamma |
|
1.68964e-05 |
1.431e+00 |
Auger electron |
|
2.29166e-05 |
5.814e+00 |
Auger electron |
|
2.48433e-05 |
1.955e+00 |
Auger electron |
|
2.73587e-05 |
4.831e-01 |
Auger electron |
|
1.19627e-04 |
6.797e-01 |
Auger electron |
|
1.22012e-04 |
1.618e-01 |
Auger electron |
|
2.83815e-04 |
2.958e-02 |
Auger electron |
|
3.14883e-04 |
1.218e-01 |
Auger electron |
|
4.22561e-04 |
3.622e-01 |
Auger electron |
|
4.49761e-04 |
1.486e+00 |
Auger electron |
|
5.04984e-04 |
1.097e-02 |
Auger electron |
|
5.42187e-04 |
5.744e-02 |
Auger electron |
|
2.96578e-03 |
1.426e-01 |
Auger electron |
|
3.07215e-03 |
5.753e-01 |
Auger electron |
|
3.52066e-03 |
3.859e-02 |
Auger electron |
|
3.66622e-03 |
1.627e-01 |
Auger electron |
|
4.28284e-03 |
1.151e-02 |
Auger electron |
|
6.65900e-03 |
9.063e-02 |
Conversion electron |
|
2.17904e-02 |
1.630e-02 |
Auger electron |
|
2.26653e-02 |
3.322e-02 |
Auger electron |
|
2.65056e-02 |
1.463e-02 |
Auger electron |
|
3.24643e-02 |
1.077e-02 |
Conversion electron |
|
4.99830e-02 |
3.453e-01 |
Conversion electron |
|
7.68738e-02 |
1.405e-01 |
Conversion electron |
|
7.71698e-02 |
3.173e-02 |
Conversion electron |
|
7.74483e-02 |
2.626e-01 |
Conversion electron |
|
8.09732e-02 |
1.050e-01 |
Conversion electron |
|
8.17880e-02 |
2.391e-02 |
Conversion electron |
|
1.80384e-01 |
6.189e-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
