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Radionuclide Dosimetric Data Sheets
Tin-121m
Summary data
General
Classification
Isotope: Sn-121m
Atomic number (Z): 50
Mass number (A): 121
Neutron number (N): 71
Radioactive decay
Decay modes: β-, Internal transition
Half-life: 43.9 [y]
Decay constant: 5.0034e-10 [1/s]
Daughters: Sn-121 (77.6%), Sb-121 (22.4%)
Radioactive daughters: Sn-121
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.03539 [MeV]
Mean photon energy: 0.00515 [MeV]
Air kerma rate constant, Γ10: 1.218e-18 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 1.218e-18 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 5.670e-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-:
5.670e-15 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 8.251e-16
[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/Sn-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/Sn-121m 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/Sn-121m 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/Sn-121m Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
1.08587e-05 |
8.210e+00 |
X-ray |
|
1.22326e-05 |
2.738e+00 |
X-ray |
|
3.43218e-03 |
2.490e-02 |
X-ray |
|
2.60930e-02 |
4.455e-02 |
X-ray |
|
2.63486e-02 |
8.315e-02 |
X-ray |
|
2.97173e-02 |
1.471e-02 |
X-ray |
|
3.71500e-02 |
1.850e-02 |
Gamma |
|
1.21854e-01 |
2.240e-01 |
Beta |
|
1.12772e-05 |
4.062e+00 |
Auger electron |
|
1.68951e-05 |
1.348e+00 |
Auger electron |
|
2.73683e-05 |
4.541e-01 |
Auger electron |
|
3.02634e-05 |
1.385e+00 |
Auger electron |
|
1.21475e-04 |
4.524e-01 |
Auger electron |
|
1.22172e-04 |
1.518e-01 |
Auger electron |
|
2.80831e-04 |
2.701e-02 |
Auger electron |
|
3.94856e-04 |
1.052e+00 |
Auger electron |
|
4.22441e-04 |
3.421e-01 |
Auger electron |
|
4.64745e-04 |
2.373e-02 |
Auger electron |
|
5.04578e-04 |
1.035e-02 |
Auger electron |
|
2.36320e-03 |
4.851e-01 |
Conversion electron |
|
2.76408e-03 |
3.583e-01 |
Auger electron |
|
2.96433e-03 |
1.348e-01 |
Auger electron |
|
3.27299e-03 |
9.127e-02 |
Auger electron |
|
3.51895e-03 |
3.647e-02 |
Auger electron |
|
5.57968e-03 |
2.389e-01 |
Conversion electron |
|
6.29000e-03 |
4.693e-02 |
Conversion electron |
|
6.67100e-03 |
1.779e-01 |
Conversion electron |
|
2.17904e-02 |
1.554e-02 |
Auger electron |
|
3.24763e-02 |
2.114e-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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