image banner

Types of radioactive decay



Penetration r is the max depth the beta electrons can reach in material. After that, all electrons are adsorbed.

\[ r = \frac{0.412}{d} E^{1.29} \]

d is density in g/cm3 (2.702 for aluminium)

E is the energy of the β rays in MeV


\[ N(x) = N_0 \exp(-\mu x) \]

\[ \ln\left(\frac{N(x)}{N_0}\right) = -\mu x \]

Half-Value Layer. Layer necessary to half the amount of incident gamma radiation

Decrease quadratically with distance. Assuming point emission,

\[ I(r) = \frac{I_0}{4\pi r^2} \]

so that

\[ \frac{I(r_1)}{I(r_2)} = \frac{r_2^2}{r_1^2} \]

doubling the distance, the intensity decreases by 4.

Last update: 29 June 2018