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Radionuclide Dosimetric Data Sheets
Iridium-194m
Summary data
General
Classification
Isotope: Ir-194m
Atomic number (Z): 77
Mass number (A): 194
Neutron number (N): 117
Radioactive decay
Decay modes: β-
Half-life: 171.0 [d]
Decay constant: 4.6915e-08 [1/s]
Daughters: Pt-194 (100.0%)
Radioactive daughters: None
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.14215 [MeV]
Mean photon energy: 2.3339 [MeV]
Air kerma rate constant, Γ10: 9.060e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 9.060e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 2.277e-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-:
2.277e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 3.739e-13
[Gy·kg/Bq·s]
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-194m 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/Ir-194m 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/Ir-194m Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
1.01469e-05 |
5.778e+00 |
X-ray |
|
2.07200e-03 |
1.625e-02 |
X-ray |
|
9.43802e-03 |
4.474e-02 |
X-ray |
|
1.11006e-02 |
4.453e-02 |
X-ray |
|
6.53020e-02 |
4.747e-02 |
X-ray |
|
6.70480e-02 |
8.110e-02 |
X-ray |
|
7.59780e-02 |
1.718e-02 |
X-ray |
|
1.11700e-01 |
8.900e-02 |
Gamma |
|
3.24000e-01 |
2.000e-02 |
Gamma |
|
3.28500e-01 |
9.300e-01 |
Gamma |
|
3.38800e-01 |
5.500e-01 |
Gamma |
|
3.90800e-01 |
3.500e-01 |
Gamma |
|
4.82600e-01 |
9.700e-01 |
Gamma |
|
5.62400e-01 |
3.500e-01 |
Gamma |
|
5.62400e-01 |
3.500e-01 |
Gamma |
|
6.00500e-01 |
6.200e-01 |
Gamma |
|
6.87800e-01 |
5.900e-01 |
Gamma |
|
1.01180e+00 |
3.600e-02 |
Gamma |
|
5.45116e-02 |
9.700e-01 |
Beta |
|
7.54487e-02 |
3.000e-02 |
Beta |
|
3.74591e-05 |
1.229e+00 |
Auger electron |
|
5.60425e-05 |
1.987e+00 |
Auger electron |
|
1.71637e-04 |
1.052e+00 |
Auger electron |
|
4.11708e-04 |
1.911e-01 |
Auger electron |
|
9.35609e-04 |
4.159e-02 |
Auger electron |
|
1.70150e-03 |
5.119e-01 |
Auger electron |
|
1.91507e-03 |
4.897e-02 |
Auger electron |
|
7.36419e-03 |
1.580e-01 |
Auger electron |
|
9.41839e-03 |
6.534e-02 |
Auger electron |
|
3.30850e-02 |
5.430e-02 |
Conversion electron |
|
9.83870e-02 |
9.011e-02 |
Conversion electron |
|
1.00133e-01 |
7.380e-02 |
Conversion electron |
|
1.09063e-01 |
4.429e-02 |
Conversion electron |
|
1.11700e-01 |
1.292e-02 |
Conversion electron |
|
2.49885e-01 |
4.560e-02 |
Conversion electron |
|
2.60185e-01 |
2.500e-02 |
Conversion electron |
|
4.03985e-01 |
1.934e-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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