| MAC | mass attenuation coefficient |
| HVL | half value layer |
| Zeff | effective atomic number |
| I0 | Initial intensity |
| I | transmitted intensity |
| fi | molar fraction of the ith constituent element |
| Ai | atomic weight of the ith constituent element |
| Zi | atomic number of the ith constituent element |
| MFP | mean free path |
| RPE | radiation protection efficiency |
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