GammaVision
®
v7 (A66-BW) 783620H / 1013
The gammas yield the following:
81 × 0.37
+ 79 × 6×10
-4
+ 100 × 9×10
-5
+ 220 × 6×10
-7
+ 302 × 4×10
-5
+ 382 × 2×10
-5
=
=
=
=
=
=
30.0
0
0
0
0
0
+ 36 × 0.534
= 19.2
+ 6 × 0.09
= 0.5
49.7
keV/disintegration
Adding the values for the electron energy and gamma energy gives the total average energy of
195.7 keV/disintegration for
133
Xe.
In the calculation of the average energy value for a nuclide, care must be taken to ensure that all radiations are counted.
NOTE
Be sure the isotope identifiers (e.g., “Xe-133") in the average energy table match the identifiers in the analysis library, otherwise, GammaVision will be unable to calculate this value correctly.
6.14. IEQ — Iodine Equivalence
The iodine equivalence (Dose Equivalent Iodine-131) calculation is used to calculate that concentration of
131
I which alone would produce the same thyroid dose as the quantity and isotopic mixture of
131
I,
132
I,
133
I,
134
I, and
135
I actually present. The thyroid dose conversion factors are given in Table III of TID-14844
37
or Table E-7 of NRC
NUREG 1.109 Rev. 1.
38
Table 15 shows the IEQ values from TID-14844.
Nuclide
131
I
132
I
133
I
134
I
135
I
Table 15. IEQ Table.
131
I Equiv
1.00000
3.610000E
!02
0.270300
1.690000E
!02
8.380000E
!02
The IEQ value is the sum of the products of the isotopic abundance and the corresponding factor for all the isotopes in both the analysis library and the table.
37
TID-14844, United States Department of Energy, Office of Scientific and Technical Information, Oak Ridge,
Tennessee.
38
Guide Number 1.109 Rev. 1, United States Nuclear Regulatory Commission, Washington, DC. October 1977.
308
