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Radionuclide Dosimetric Data Sheets
Iridium-191m
Summary data
General
Classification
Isotope: Ir-191m
Atomic number (Z): 77
Mass number (A): 191
Neutron number (N): 114
Radioactive decay
Decay modes: Internal transition
Half-life: 4.94 [s]
Decay constant: 1.4031e-01 [1/s]
Daughters: Ir-191 (100.0%)
Radioactive daughters: None
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.09707 [MeV]
Mean photon energy: 0.07643 [MeV]
Air kerma rate constant, Γ10: 1.385e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 1.385e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.555e-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-:
1.555e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 1.225e-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/Ir-191m 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/Ir-191m 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/Ir-191m Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
4.54779e-05 |
1.267e+01 |
X-ray |
|
1.99623e-03 |
5.942e-02 |
X-ray |
|
8.06831e-03 |
1.127e-02 |
X-ray |
|
9.09081e-03 |
1.947e-02 |
X-ray |
|
9.16922e-03 |
1.716e-01 |
X-ray |
|
1.07358e-02 |
1.511e-01 |
X-ray |
|
1.09194e-02 |
3.142e-02 |
X-ray |
|
1.25485e-02 |
2.914e-02 |
X-ray |
|
6.34550e-02 |
1.641e-01 |
X-ray |
|
6.50999e-02 |
2.815e-01 |
X-ray |
|
7.34138e-02 |
3.070e-02 |
X-ray |
|
7.37750e-02 |
5.937e-02 |
X-ray |
|
7.58295e-02 |
1.385e-02 |
X-ray |
|
1.29431e-01 |
2.610e-01 |
Gamma |
|
3.53720e-05 |
2.409e+00 |
Auger electron |
|
1.71325e-04 |
4.193e+00 |
Auger electron |
|
3.53109e-04 |
8.480e-01 |
Auger electron |
|
3.59350e-04 |
1.851e-01 |
Auger electron |
|
8.52030e-04 |
1.591e-01 |
Auger electron |
|
1.64683e-03 |
2.012e+00 |
Auger electron |
|
1.84986e-03 |
1.783e-01 |
Auger electron |
|
7.13203e-03 |
6.162e-01 |
Auger electron |
|
9.10722e-03 |
2.501e-01 |
Auger electron |
|
1.11109e-02 |
2.485e-02 |
Auger electron |
|
2.89870e-02 |
3.501e-01 |
Conversion electron |
|
3.06320e-02 |
3.568e-01 |
Conversion electron |
|
3.93070e-02 |
2.207e-01 |
Conversion electron |
|
4.18460e-02 |
6.501e-02 |
Conversion electron |
|
5.13520e-02 |
1.575e-02 |
Auger electron |
|
5.31170e-02 |
5.875e-01 |
Conversion electron |
|
1.16035e-01 |
8.667e-02 |
Conversion electron |
|
1.16572e-01 |
2.496e-02 |
Conversion electron |
|
1.18217e-01 |
1.428e-02 |
Conversion electron |
|
1.26892e-01 |
2.999e-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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