Weakly Penetrating Particles This includes low energy electrons, protons, a-particles and heavy ions. The rate of energy
loss in matter increases as the charge and mass of the particle increase, but the
conversion of particle energy in scintillation light decreases. The number of photons
produced by an 5.4 MeV a-particle is only 70-80% of a gamma photon with the same energy. Apart
from the emitted energy and the specific scintillator, the energy resolution for particles
also depends on the surface treatment of the material.
The following aspects should be considered. The entrance window of the
detector should be very thin so that the incident radiation is not absorbed; aluminized
mylar windows are normally used. For heavy ions, the detector is best operated in a
light-tight environment without a window. The thickness of mylar windows can vary between
1.5 mm and 100 m m. |