f.
Plastic or glass shielding permits operator to view work
Gamma and X rays
a.
Theoretically, this radiation cannot be absorbed completely
by shielding
b.
Shield that will pass only a nonhazardous fraction of the
original radiation should be objective
c.
Effective materials for gamma shields are elements having
high densities
d.
Compromises must be made, however, on cost and weight
Neutrons
a.
Neutrons present the most difficult shielding problems
b.
Thickness of shield depends on composition and energy of
neutrons
c.
Gamma rays are produced in the attenuation of neutrons and
.in the fission process - materials used to fabricate the
shield must guard against bothtypes of radiation
dad.
Hydrogenous materials are excellent for neutron shielding
Positrons emitted from cyclotron require beta and ganma
shielding
Distance from source of radiation
Distance may be used as a means of control
Distance from alpha and beta particles where no exposure is
received can be ascertained
Gamma and X-ray exposure decreases with distance in the same
manner that the intensity of light is never completely eliminated
3 - 3
DO’ ARCHIVES