Electromagnetic radiations and electrons have low LETs compared to
heavy particles (e.g.,a-particles), which have high LETs. Explain.
The range of an a-particle is almost equal to the total path traveled,
whereas the range of an electron is less than the total path traveled by
the particle. Explain.
Indicate how the range of a charged particle is affected by the follow-
ing conditions:
(a) As the mass increases, the range increases or decreases.
(b) As the energy of the particle increases, the range increases or
decreases.
(c) As the charge of the particle increases, the range increases or
decreases.
Define Bragg ionization and straggling of ranges. Which has more strag-
gling, an a-particle or an electron? Explain.
How is bremsstrahlung produced? Does its production increase
or decrease with increasing kinetic energy of the electron and the
atomic number of the absorber? Explain why^32 P is stored in plastic
containers.
Discuss the mechanism of the photoelectric effect. Does this process
increase or decrease with increasing energy of the g-ray and with
increasing atomic number of the absorber?
A 0.495-MeV g-ray interacts with a K-shell electron by the photo-
electric process. If the binding energy of the K-shell electron is 28 keV,
what happens to the rest of the photon energy?
(a) Explain the Compton scattering of electromagnetic radiations in
the absorber.
(b) Does it depend on the atomic number of the absorber?
(c) How is it affected by the g-ray energy?
If a relatively high-energy g-ray is scattered at 180° (backscattered) by
the Compton scattering, what is the maximum energy of the scattered
photon?
(a) How does pair production occur?
(b) Why does pair production require a minimum of 1.02 MeV for g-
ray energy?
(c) Is this process affected by the atomic number of the absorber and
the photon energy?
Which electrons of the absorber atom are involved in the photoelectric
and Compton interactions of electromagnetic radiations?
(a) Discuss the attenuation of a photon beam passing through an
absorber.
(b) Does it depend on the density and the atomic number of the
absorber?
(c) Define the half-value layer (HVL) of an absorbing material for a
g-ray energy.
