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Radionuclide Dosimetric Data Sheets
Protactinium-237
Summary data
General
Classification
Isotope: Pa-237
Atomic number (Z): 91
Mass number (A): 237
Neutron number (N): 146
Radioactive decay
Decay modes: β-
Half-life: 8.7 [m]
Decay constant: 1.3279e-03 [1/s]
Daughters: U-237 (100.0%)
Radioactive daughters: U-237
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.57804 [MeV]
Mean photon energy: 0.60947 [MeV]
Air kerma rate constant, Γ10: 2.291e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 2.291e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 9.261e-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-:
9.261e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 9.765e-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/Pa-237 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/Pa-237 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/Pa-237 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/Pa-237 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
7.53164e-05 |
5.726e+00 |
X-ray |
|
3.33010e-03 |
2.550e-02 |
X-ray |
|
3.10100e-01 |
1.739e-02 |
Gamma |
|
4.98700e-01 |
2.421e-02 |
Gamma |
|
5.29400e-01 |
1.500e-01 |
Gamma |
|
5.40700e-01 |
9.207e-02 |
Gamma |
|
5.54900e-01 |
1.534e-02 |
Gamma |
|
8.53700e-01 |
3.410e-01 |
Gamma |
|
8.65000e-01 |
1.569e-01 |
Gamma |
|
4.67180e-01 |
5.297e-01 |
Beta |
|
5.18219e-01 |
2.099e-02 |
Beta |
|
5.94531e-01 |
2.399e-01 |
Beta |
|
8.12589e-01 |
1.899e-01 |
Beta |
|
7.16207e-05 |
1.618e+00 |
Auger electron |
|
1.64236e-04 |
1.017e-02 |
Auger electron |
|
2.03161e-04 |
1.465e+00 |
Auger electron |
|
2.03416e-04 |
8.512e-01 |
Auger electron |
|
6.62103e-04 |
5.492e-01 |
Auger electron |
|
1.52706e-03 |
1.800e-02 |
Auger electron |
|
2.53252e-03 |
3.623e-01 |
Auger electron |
|
3.07605e-03 |
7.225e-02 |
Auger electron |
|
7.01040e-03 |
3.961e-01 |
Conversion electron |
|
1.02142e-02 |
1.250e-02 |
Auger electron |
|
1.13000e-02 |
1.420e-01 |
Conversion electron |
|
2.32320e-02 |
1.989e-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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