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Radionuclide Dosimetric Data Sheets

Xenon-121

Summary data

General

Classification

Isotope:  Xe-121
Atomic number (Z):  54
Mass number (A):  121
Neutron number (N):  67

Radioactive decay

Decay modes:  β+, Electron capture
Half-life:  40.1 [m]
Decay constant:  2.8809e-04 [1/s]
Daughters:  I-121 (100.0%)
Radioactive daughters:  I-121

Dosimetric constants

Mean alpha energy:  0.0 [MeV]
Mean electron energy:  0.58189 [MeV]
Mean photon energy:  1.47199 [MeV]
Air kerma rate constant, Γ10:  3.358e-17 [Gy·m2/Bq·s]
Air kerma coefficient, Kair:  5.217e-17 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or electrons), Δwp:  9.323e-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-:  9.323e-14 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp:  2.358e-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/Xe-121 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/Xe-121 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/Xe-121 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/Xe-121 Summary Spectrum.csv

 

Energy [MeV]

Yield [#/nt] if > 0.01

Radiation type

1.52658e-05

8.990e+00

X-ray

3.92520e-03

2.625e-02

X-ray

4.21605e-03

1.539e-02

X-ray

2.83065e-02

1.548e-01

X-ray

2.86096e-02

2.873e-01

X-ray

3.22368e-02

2.672e-02

X-ray

3.22942e-02

5.182e-02

X-ray

3.30298e-02

1.090e-02

X-ray

8.01000e-02

2.394e-02

Gamma

9.57000e-02

4.536e-02

Gamma

1.32800e-01

1.096e-01

Gamma

1.75800e-01

4.284e-02

Gamma

1.77700e-01

1.071e-02

Gamma

2.52700e-01

1.260e-01

Gamma

3.00700e-01

2.583e-02

Gamma

3.10500e-01

5.418e-02

Gamma

4.33400e-01

1.058e-02

Gamma

4.45200e-01

7.812e-02

Gamma

5.11000e-01

9.609e-01

Annihilation photon

5.29100e-01

1.386e-02

Gamma

6.49700e-01

1.537e-02

Gamma

9.31000e-01

1.336e-02

Gamma

1.02390e+00

1.109e-02

Gamma

1.03560e+00

1.058e-02

Gamma

2.54470e+00

1.071e-02

Gamma

2.64340e+00

2.205e-02

Gamma

1.05698e+00

2.710e-02

Positron

1.07372e+00

1.807e-02

Positron

1.11899e+00

5.119e-02

Positron

1.14568e+00

3.614e-02

Positron

1.18120e+00

4.517e-02

Positron

1.20108e+00

4.617e-02

Positron

1.26266e+00

2.008e-01

Positron

2.70197e-05

1.348e+00

Auger electron

2.89514e-05

4.333e+00

Auger electron

1.25059e-04

4.971e-01

Auger electron

3.05737e-04

9.508e-02

Auger electron

4.76981e-04

1.154e+00

Auger electron

5.78509e-04

5.493e-02

Auger electron

3.20497e-03

4.525e-01

Auger electron

3.83965e-03

1.337e-01

Auger electron

2.35598e-02

4.647e-02

Auger electron

2.46360e-02

1.697e-02

Conversion electron

2.75866e-02

2.080e-02

Auger electron

4.69360e-02

2.969e-02

Conversion electron

6.25360e-02

6.195e-02

Conversion electron

9.11455e-02

1.049e-02

Conversion electron

9.96360e-02

3.237e-02

Conversion 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

 

 

 

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