| Behaviour of Alphas-I |
- Charge particles interact with nucleus and electrons through Coulombic interaction and it ionizes the medium.
- It is a general practice to refer to terms like Specific Ionization, Stopping Power and Range. These are defined as follows.
- Specific Ionization is expressed as the number of ion-pairs produced per unit distance travelled.
- Stopping Power is expressed in energy lost per unit distance travelled. This is also called LET (Linear Energy Transfer).
- Range is the total distance travelled before the radiation is absorbed.
- The Count rate of alphas as a function of absorber thickness in air is shown in the following figure.
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- The almost abrupt fall in intensity can be attributed to the almost mono-energetic spectra of alphas.
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- The range of alphas in other materials relative to that in air is found by using the Bragg-Kleeman Rule
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- Alphas do not pose any shielding problem, though they affect tissues. More discussion on this will follow later.
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