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Chapter 9
Medical Applications of
14 MeV Neutrons
9.1 INTRODUCTION
Attenuation of neutron beam, as shown in Figure 9.1, by the specimen depends
on thickness and the attenuation coecient similar to gamma ray as follows:
I
t
= I
0
exp (−Σt)
where
I
t
is the transmitted neutron intensity (n/cm
2
/s)
I
0
is the incident neutron intensity (n/cm
2
/s)
t is the specimen thickness (cm)
Σ is the macroscopic cross section (cm
−1
)
Σ is equivalent to the linear attenuation coecient of gamma ray (μ) and is the
characteristic of elements in the specimen. Σ and μ are the products of atom
density of elements contained in the specimen (in atoms/cm
3
) and their eec-
tive micro ...