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 Bremsstrahlung 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 |