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with a screen is dependent upon the number of 6Li
atoms in a fixed volume. The neutron attenuation co-
efficients of any material can be determined using the
Equation 5.3. Where t is the thickness of the material,
X is the atomic cross section in barns, N is the num-
ber of 6Li atoms per cm3, I◦ is the incident neutron flux,
I is the transmitted neutron flux.

I = I(◦–NXt) (5.3)

Contrast of radiograph in neutron radiography is
given the value of I and it is proportional with the value
of attenuation coefficients. The contrast registered on
the radiograpy film or CCD camera record a details of
object internal.

5.3 Principle of Neutron Tomogra-
phy

There are many ways to reconstruct data to form to-
mography image. Neutron tomography can be recon-
structed from radiograph obtained in neutron radiog-
raphy technique. Even though tomography image can
be reconstructed from many data configuration, this
chapter will discuss tomography image formation prin-
ciple based on radiography technique.

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