放射性是不稳定原子核因辐射失去能量的过程。它以Becquerels（BQ）进行测量。
1 Ci = 37,000,000,000 β
1 β = 2.7027e-11 Ci
例子:
将15 居里转换为beta颗粒：
15 Ci = 555,000,000,000 β
| 居里 | beta颗粒 |
|---|---|
| 0.01 Ci | 370,000,000 β |
| 0.1 Ci | 3,700,000,000 β |
| 1 Ci | 37,000,000,000 β |
| 2 Ci | 74,000,000,000 β |
| 3 Ci | 111,000,000,000 β |
| 5 Ci | 185,000,000,000 β |
| 10 Ci | 370,000,000,000 β |
| 20 Ci | 740,000,000,000 β |
| 30 Ci | 1,110,000,000,000 β |
| 40 Ci | 1,480,000,000,000 β |
| 50 Ci | 1,850,000,000,000 β |
| 60 Ci | 2,220,000,000,000 β |
| 70 Ci | 2,590,000,000,000 β |
| 80 Ci | 2,960,000,000,000 β |
| 90 Ci | 3,330,000,000,000 β |
| 100 Ci | 3,700,000,000,000 β |
| 250 Ci | 9,250,000,000,000 β |
| 500 Ci | 18,500,000,000,000 β |
| 750 Ci | 27,750,000,000,000 β |
| 1000 Ci | 37,000,000,000,000 β |
| 10000 Ci | 370,000,000,000,000 β |
| 100000 Ci | 3,700,000,000,000,000 β |
规则