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Radionuclide Dosimetric Data Sheets

Protactinium-227

Summary data

General

Classification

Isotope:  Pa-227
Atomic number (Z):  91
Mass number (A):  227
Neutron number (N):  136

Radioactive decay

Decay modes:  α, Electron capture
Half-life:  38.3 [m]
Decay constant:  3.0163e-04 [1/s]
Daughters:  Ac-223 (85.0%), Th-227 (15.0%)
Radioactive daughters:  Ac-223, Th-227

Dosimetric constants

Mean alpha energy:  5.5649 [MeV]
Mean electron energy:  0.02261 [MeV]
Mean photon energy:  0.02335 [MeV]
Air kerma rate constant, Γ10:  7.373e-18 [Gy·m2/Bq·s]
Air kerma coefficient, Kair:  7.373e-18 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or electrons), Δwp:  8.952e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δα:  8.916e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δβ-,β+,e-:  3.623e-15 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp:  3.741e-15 [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-227 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-227 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/Pa-227 Summary Spectrum.csv

 

Energy [MeV]

Yield [#/nt] if > 0.01

Radiation type

7.95587e-05

6.043e+00

X-ray

8.22404e-05

1.721e+00

X-ray

2.97508e-03

3.180e-02

X-ray

1.26589e-02

6.604e-02

X-ray

1.29764e-02

2.307e-02

X-ray

1.52434e-02

1.353e-02

X-ray

1.57834e-02

4.797e-02

X-ray

1.62775e-02

1.395e-02

X-ray

1.84875e-02

1.055e-02

X-ray

6.46200e-02

6.120e-02

Gamma

9.03299e-02

3.103e-02

X-ray

9.37949e-02

5.016e-02

X-ray

1.06073e-01

1.121e-02

X-ray

1.10050e-01

1.242e-02

Gamma

3.11369e-05

1.380e+00

Auger electron

5.13466e-05

4.145e-01

Auger electron

1.25901e-04

1.636e+00

Auger electron

1.32341e-04

4.583e-01

Auger electron

1.86641e-04

9.093e-01

Auger electron

1.87940e-04

2.593e-01

Auger electron

4.90702e-04

2.523e-01

Auger electron

4.92788e-04

6.757e-02

Auger electron

1.29567e-03

1.302e-01

Auger electron

1.43166e-03

2.678e-02

Auger electron

2.26826e-03

5.228e-01

Auger electron

2.31238e-03

1.504e-01

Auger electron

2.66167e-03

8.684e-02

Auger electron

2.72493e-03

2.577e-02

Auger electron

9.65672e-03

1.296e-01

Auger electron

9.69095e-03

3.961e-02

Auger electron

1.26942e-02

6.373e-02

Auger electron

1.28128e-02

1.969e-02

Auger electron

1.85520e-02

1.513e-02

Conversion electron

2.25520e-02

3.102e-02

Conversion electron

2.32370e-02

9.138e-02

Conversion electron

2.65170e-02

8.258e-02

Conversion electron

2.67520e-02

2.139e-02

Conversion electron

2.84520e-02

1.797e-02

Conversion electron

3.08520e-02

2.006e-02

Conversion electron

3.67520e-02

1.613e-02

Conversion electron

3.84961e-02

5.482e-02

Conversion electron

4.24000e-02

1.880e-02

Conversion electron

6.35586e+00

6.797e-02

Alpha

6.37488e+00

2.237e-02

Alpha

6.40050e+00

8.087e-02

Alpha

6.41417e+00

1.299e-01

Alpha

6.42233e+00

1.007e-01

Alpha

6.46398e+00

4.319e-01

Alpha

1.14081e-01

6.797e-02

Alpha recoil

1.14422e-01

2.237e-02

Alpha recoil

1.14882e-01

8.087e-02

Alpha recoil

1.15127e-01

1.299e-01

Alpha recoil

1.15274e-01

1.007e-01

Alpha recoil

1.16021e-01

4.319e-01

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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