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Radionuclide Dosimetric Data Sheets

Terbium-149m

Isotope:  Tb-149m
Atomic number (Z):  65
Mass number (A):  149
Neutron number (N):  84

Decay modes:  α, β+, Electron capture
Half-life:  4.16 [m]
Decay constant:  2.7770e-03 [1/s]
Daughters:  Gd-149 (100.0%), Eu-145 (0.022%)
Radioactive daughters:  Gd-149, Eu-145

Mean alpha energy:  0.0009 [MeV]
Mean electron energy:  0.20905 [MeV]
Mean photon energy:  1.37476 [MeV]
Air kerma rate constant, Γ₁₀:  4.275e-17 [Gy·m²/Bq·s]
Air kerma coefficient, K_air:  5.165e-17 [Gy·m²/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or electrons), Δ_wp:  3.364e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δ_α:  1.442e-16 [Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δ_β-,β+,e-:  3.349e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δ_p:  2.203e-13 [Gy·kg/Bq·s]

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/Tb-149m DPK.csv

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/Tb-149m Summary Spectrum.csv

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/Tb-149m Beta Spectrum.csv

 

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/Tb-149m Summary Spectrum.csv

 

Energy [MeV]	Yield [#/nt] if > 0.01	Radiation type
1.94295e-05	7.312e+00	X-ray
1.09477e-03	1.114e-02	X-ray
6.04290e-03	5.128e-02	X-ray
6.71540e-03	3.315e-02	X-ray
4.23559e-02	1.822e-01	X-ray
4.30603e-02	3.276e-01	X-ray
4.86161e-02	3.329e-02	X-ray
4.87612e-02	6.440e-02	X-ray
5.00239e-02	1.420e-02	X-ray
7.50000e-02	1.261e-02	Gamma
1.65000e-01	7.273e-02	Gamma
5.11000e-01	4.599e-01	Annihilation photon
6.30700e-01	2.812e-02	Gamma
6.51000e-01	3.258e-01	Gamma
7.73000e-01	3.394e-02	Gamma
7.96000e-01	9.698e-01	Gamma
8.53000e-01	1.164e-02	Gamma
9.88000e-01	1.940e-02	Gamma
1.68140e+00	2.424e-02	Gamma
8.37334e-01	2.299e-01	Positron
1.68638e-05	4.914e-01	Auger electron
1.13380e-04	3.290e+00	Auger electron
1.23655e-04	2.705e-01	Auger electron
1.82306e-04	5.139e-01	Auger electron
5.72509e-04	1.037e-01	Auger electron
8.97954e-04	1.108e+00	Auger electron
1.07582e-03	7.524e-02	Auger electron
4.77203e-03	4.074e-01	Auger electron
5.92810e-03	1.429e-01	Auger electron
7.11885e-03	1.241e-02	Auger electron
3.47386e-02	2.842e-02	Auger electron
4.11460e-02	1.407e-02	Auger electron
1.14697e-01	2.587e-02	Conversion electron

 

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

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

 

 

 

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