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Radionuclide Dosimetric Data Sheets
Yttrium-85
Summary data
General
Classification
Isotope: Y-85
Atomic number (Z): 39
Mass number (A): 85
Neutron number (N): 46
Radioactive decay
Decay modes: β+, Electron capture
Half-life: 2.68 [h]
Decay constant: 7.1844e-05 [1/s]
Daughters: Sr-85m (100.0%)
Radioactive daughters: Sr-85m
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.48814 [MeV]
Mean photon energy: 1.07946 [MeV]
Air kerma rate constant, Γ10: 2.061e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 4.631e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 7.821e-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-:
7.821e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 1.729e-13
[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/Y-85 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/Y-85 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/Y-85 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/Y-85 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
2.09354e-05 |
2.814e+00 |
X-ray |
|
1.40549e-02 |
5.941e-02 |
X-ray |
|
1.41246e-02 |
1.141e-01 |
X-ray |
|
1.57975e-02 |
1.690e-02 |
X-ray |
|
5.04440e-01 |
6.000e-01 |
Gamma |
|
5.11000e-01 |
1.328e+00 |
Annihilation photon |
|
9.13890e-01 |
9.000e-02 |
Gamma |
|
4.75381e-01 |
3.830e-02 |
Positron |
|
6.58302e-01 |
3.830e-01 |
Positron |
|
8.88290e-01 |
2.419e-01 |
Positron |
|
1.36397e-05 |
7.844e-01 |
Auger electron |
|
7.49562e-05 |
7.822e-01 |
Auger electron |
|
9.39289e-05 |
3.322e-01 |
Auger electron |
|
1.00513e-04 |
7.132e-02 |
Auger electron |
|
1.09925e-04 |
3.791e-02 |
Auger electron |
|
1.57335e-03 |
3.271e-01 |
Auger electron |
|
1.71374e-03 |
2.909e-02 |
Auger electron |
|
1.20238e-02 |
6.790e-02 |
Auger electron |
|
1.37890e-02 |
2.301e-02 |
Auger 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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