In: Physics
Ionization Chamber region is used to detect high energetic ? and ? paricles while Proportinal region is suitable to detect ? and ? particles with low energy. Why?
As an energetic charged particle passes through a gas, its electrostatic field will dislodge orbital electrons from atoms sufficiently close to its path. In each case, the negatively charged electron dislodged and the more massive positive ion comprising the remainder of the atom form an ion pair. The minimum energy (in electron volts) required for such ion pair formation in a given gas is called the ionization potential. This value differs markedly for different gases and is dependent on the type and energy of the charged particle. A more meaningful value is the average energy lost by the particle in producing one ion pair, which is nearly independent of particle energy and type (and is about 35 eV).The rate of energy loss will depend on the energy and type of charged particle. Alpha particles will create intense ionization (-‐104-‐105 ion pairs /cm of path length) whereas β-‐particles will produce 102-‐103 ion pairs/cm and the passage of γ-‐rays will result in 1-‐10 ion pairs/cm