List of units of measurement relevant to radiation protection
This is a comparative list of units of measurement relevant to radiation protection
| Measurand | SI unit | obsolete units | Remarks | |
|---|---|---|---|---|
| Activity (A) | Number of decays per unit of time |
Becquerel 1 Bq = 1 / s |
1 Curie (Ci) = 3.7 · 10 10 Bq 1 Rutherford (Rd) = 10 6 Bq 1 Stat (St) = 1.345 · 10 4 Bq |
1 Ci is approximately the activity of 1 g 226 Ra . The stat was only used when specifying the radioactivity of medicinal waters. |
| Absorbed dose (D) | Absorbed energy per unit of mass |
Gray 1 Gy = 1 J / kg |
1 Rad (rad, rd) = 0.01 Gy 1 Rep (rep) = 0.01075 Gy |
Gray is also the unit of measure for kerma |
| Equivalent dose (H) | Energy dose, multiplied by a weighting factor w, of the biological activity indicates |
Sievert 1 Sv = 1 J / kg |
1 Rem (rem) = 0.01 Sv | For X-ray , gamma and beta radiation w is 1; 1 Gy then corresponds to 1 Sv. For other radiation, the factor increases up to 20. |
| Ion dose (J) | Ions generated by radiation per unit of mass | C / kg | 1 X-ray (R) = 2.58 · 10 −4 C / kg | Which absorbed dose corresponds to the ion dose depends on the material, radiation type and radiation energy. In dry air, 1 C / kg corresponds to about 35 Gy; this results in the rule of thumb 1 R ≈ 1 rad (more precisely 0.9 rad would be). |
| Activity concentration | Activity per unit volume | Bq / m³ | 1 eman = 10 −10 Ci / l = 3700 Bq / m³ 1 ME = 3.64 eman = 13.4545 Bq / l |
The eman and the mache unit (ME) were used to indicate the radon concentration in water and air. |
| Absorbed dose rate | Absorbed dose per unit of time | Gy / s | 1 rad / s = 3600 rad / h | |
| Dose rate equivalent | Equivalent dose per unit of time | Sv / s | 1 rem / s = 3600 rem / h | often given in μSv per hour or mSv per year (1 μSv / h = 8.76 mSv / a); the natural radiation background in Germany is between 0.6 mSv / a and 1.2 mSv / a |