Rad
The Rad is a measure of the Total Ionising Dose (TiD) in the CGS system. In SI units, it has been replaced by the Gray (Gy), and its use is strongly discouraged, but it is still common in the US.
It is defined as
D = \frac{d\epsilon}{dm}
where, d\epsilon is the energy absorbed by the material, and dm is the mass of the device.
Relationship to Other Units
1\ rad = 0.01\ Gy \quad 1\ Gy = 100\ rad
1\ rad = 0.01\ J/Kg \quad 1\ J/Kg = 100\ rad
Effects on Humans
| Dose | Description |
|---|---|
| 25 Rad | Lowest dose to cause clinically observable blood changes |
| 400 Rad | Whole body LD50 |
| 1 kRad | Whole body LD100 |
Effects on Electronics
| Dose | Description |
|---|---|
| 1-20 kRad | Typical radiation tolerance of ordinary microchips |
| 1 MRad | Typical radiation tolerance of radiation-hardened microchips |