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Radionuclide Dosimetric Data Sheets

Actinium-224

Summary data

General

Classification

Isotope:  Ac-224
Atomic number (Z):  89
Mass number (A):  224
Neutron number (N):  135

Radioactive decay

Decay modes:  α, Electron capture
Half-life:  2.78 [h]
Decay constant:  6.9259e-05 [1/s]
Daughters:  Ra-224 (90.9%), Fr-220 (9.1%)
Radioactive daughters:  Ra-224, Fr-220

Dosimetric constants

Mean alpha energy:  0.5662 [MeV]
Mean electron energy:  0.04901 [MeV]
Mean photon energy:  0.23248 [MeV]
Air kerma rate constant, Γ10:  2.304e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair:  2.304e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or electrons), Δwp:  9.857e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δα:  9.072e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δβ-,β+,e-:  7.852e-15 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp:  3.725e-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/Ac-224 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/Ac-224 Summary 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/Ac-224 Summary Spectrum.csv

 

Energy [MeV]

Yield [#/nt] if > 0.01

Radiation type

6.05941e-05

1.264e+00

X-ray

7.12229e-05

1.522e+01

X-ray

2.88379e-03

7.805e-02

X-ray

1.06609e-02

1.269e-02

X-ray

1.21973e-02

2.159e-02

X-ray

1.23447e-02

1.899e-01

X-ray

1.48529e-02

3.857e-02

X-ray

1.53013e-02

1.434e-01

X-ray

1.79232e-02

3.122e-02

X-ray

8.44000e-02

1.520e-02

Gamma

8.57602e-02

2.252e-01

X-ray

8.88641e-02

3.678e-01

X-ray

9.98380e-02

4.189e-02

X-ray

1.00546e-01

8.152e-02

X-ray

1.03272e-01

1.030e-02

X-ray

1.03453e-01

2.056e-02

X-ray

1.31350e-01

2.690e-01

Gamma

2.15750e-01

5.229e-01

Gamma

2.56146e-05

4.187e+00

Auger electron

3.06891e-05

3.470e-01

Auger electron

1.20249e-04

4.233e+00

Auger electron

1.20647e-04

3.576e-01

Auger electron

1.35371e-04

1.854e-02

Auger electron

1.81185e-04

2.390e+00

Auger electron

1.84984e-04

1.996e-01

Auger electron

4.63898e-04

6.035e-01

Auger electron

5.05362e-04

7.109e-02

Auger electron

1.15505e-03

2.792e-02

Auger electron

1.43391e-03

1.679e-01

Auger electron

2.19015e-03

1.018e-01

Auger electron

2.21570e-03

1.351e+00

Auger electron

2.56102e-03

1.612e-02

Auger electron

2.58614e-03

2.170e-01

Auger electron

3.11171e-03

1.215e-02

Auger electron

3.25550e-03

1.473e-02

Conversion electron

5.97000e-03

1.091e-02

Conversion electron

8.75550e-03

1.129e-02

Conversion electron

9.21579e-03

1.796e-02

Auger electron

9.31739e-03

3.682e-01

Auger electron

1.22421e-02

1.783e-01

Auger electron

1.51976e-02

2.045e-02

Auger electron

2.70300e-02

5.275e-02

Conversion electron

2.97700e-02

1.012e-02

Conversion electron

6.58400e-02

1.333e-01

Conversion electron

6.84262e-02

1.681e-02

Auger electron

6.89440e-02

1.029e-01

Conversion electron

8.06263e-02

6.572e-02

Conversion electron

8.44000e-02

2.219e-02

Conversion electron

1.11430e-01

3.173e-02

Conversion electron

6.05985e+00

2.000e-02

Alpha

6.14215e+00

2.338e-02

Alpha

6.20707e+00

1.087e-02

Alpha

6.21385e+00

1.863e-02

Alpha

1.10251e-01

2.000e-02

Alpha recoil

1.11748e-01

2.338e-02

Alpha recoil

1.12929e-01

1.087e-02

Alpha recoil

1.13052e-01

1.863e-02

Alpha recoil

 

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

 

 

 

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