Summary data

General

Classification

Isotope: Br-85
Atomic number (Z): 35
Mass number (A): 85
Neutron number (N): 50

Radioactive decay

Decay modes: β-
Half-life: 2.9 [m]
Decay constant: 3.9836e-03 [1/s]
Daughters: Kr-85m (99.8%), Kr-85 (0.221%)
Radioactive daughters: Kr-85m, Kr-85

Dosimetric constants

Mean alpha energy: 0.0 [MeV]
Mean electron energy: 1.03842 [MeV]
Mean photon energy: 0.06604 [MeV]
Air kerma rate constant, Γ₁₀: 2.343e-18 [Gy·m²/Bq·s]
Air kerma coefficient, K_air: 2.343e-18 [Gy·m²/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or electrons), Δ_wp: 1.664e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δ_α: 0.000e+00 [Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δ_β-,β+,e-: 1.664e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δ_p: 1.058e-14 [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/Br-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/Br-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/Br-85 Summary Spectrum.csv

Energy [MeV]	Yield [#/nt] if > 0.01	Radiation type
8.02410e-01	2.557e-02	Gamma
9.24630e-01	1.630e-02	Gamma
2.89858e-01	2.223e-02	Beta
1.06606e+00	9.571e-01	Beta

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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