DOE-HDBK-1019/1-93
Atomic and Nuclear Physics
INTERACTION OF RADIATION WITH MATTER
INTERACTION OF RADIATION WITH MATTER
Different types of radiation interact with matter in widely different ways. A large,
massive, charged alpha particle cannot penetrate a piece of paper and even has
a limited range in dry air.
A neutrino, at the other extreme, has a low
probability of interacting with any matter, even if it passed through the diameter
of the earth.
EO 5.1
DESCRIBE interactions of the following with matter:
a.
Alpha particle
c.
Positron
b.
Beta particle
d.
Neutron
EO 5.2
DESCRIBE the following ways that gamma radiation interacts
with matter:
a.
Photoelectric effect
b.
Compton scattering
c.
Pair production
Interaction of Radiation With Matter
Radiation can be classified into two general groups, charged and uncharged; therefore, it may be
expected that interactions with matter fall into two general types. Charged particles directly
ionize the media through which they pass, while uncharged particles and photons can cause
ionization only indirectly or by secondary radiation.
A moving charged particle has an electrical field surrounding it, which interacts with the atomic
structure of the medium through which it is passing. This interaction decelerates the particle and
accelerates electrons in the atoms of the medium. The accelerated electrons may acquire enough
energy to escape from the parent atom. This process, whereby radiation "strips" off orbital
electrons, is called ionization. Uncharged moving particles have no electrical field, so they can
only lose energy and cause ionization by such means as collisions or scattering. A photon can
lose energy by the photoelectric effect, Compton effect, or pair production.
Rev. 0
Page 63
NP-01
