SIGNIFICANT RADIATION PARAMETERS OF COMMONLY USED ISOTOPES


SIGNIFICANT RADIATION PARAMETERS OF COMMONLY USED ISOTOPES

Nuclide Principal Radiation Half-Life Ingestion Limit, uCi Shielding Notes
H-3 Beta
18.6 keV
12.3y 80000 None --------
C-14 Beta
156 keV
5730y 2000 None --------
P-32 Beta
1700 keV
14.3 d 600 Acrylic. Plexiglas (1cm) The Beta s will produce x-rays by Bremstrahlung if they interact with and high atomic number material. Lead or other metals should not be used for shielding. Contact RSO for guidance.
S-35 Beta
167 keV
87 d 1000 None ------
Ca-45 Beta
257 keV
163 d 2000 See P-32 -------
Cr-51 Gamma
320 keV
28 d 40000 HVL=1.7mm --------
Co-57 Gamma
122 keV
271 d 4000 HVL=.2mm --------
I-125 Gamma
27 keV
60 d 40 HVL=.02mm Volatilization is the most significant hazard. Work with a volatile iodine compound whose activity exceeds 1 millicuries must be done in a fume hood unless a bioassay program is established for the user.
I-131 Beta
606 keV
8 d 30 HVL=2.3mm See I-125
Gamma
364 keV