放射能は、不安定な原子核が放射によってエネルギーを失うプロセスです。Beckerels（BQ）で測定されます。
1 R = 0.01 n/cm²/s
1 n/cm²/s = 100 R
例:
15 Roentgenを中性子流束に変換します。
15 R = 0.15 n/cm²/s
| Roentgen | 中性子流束 |
|---|---|
| 0.01 R | 0 n/cm²/s |
| 0.1 R | 0.001 n/cm²/s |
| 1 R | 0.01 n/cm²/s |
| 2 R | 0.02 n/cm²/s |
| 3 R | 0.03 n/cm²/s |
| 5 R | 0.05 n/cm²/s |
| 10 R | 0.1 n/cm²/s |
| 20 R | 0.2 n/cm²/s |
| 30 R | 0.3 n/cm²/s |
| 40 R | 0.4 n/cm²/s |
| 50 R | 0.5 n/cm²/s |
| 60 R | 0.6 n/cm²/s |
| 70 R | 0.7 n/cm²/s |
| 80 R | 0.8 n/cm²/s |
| 90 R | 0.9 n/cm²/s |
| 100 R | 1 n/cm²/s |
| 250 R | 2.5 n/cm²/s |
| 500 R | 5 n/cm²/s |
| 750 R | 7.5 n/cm²/s |
| 1000 R | 10 n/cm²/s |
| 10000 R | 100 n/cm²/s |
| 100000 R | 1,000 n/cm²/s |
Inayam