Page 115 - bukuneutron

age. In neutron radiography, a scintillation screen or
converter is used to convert thermal neutron to the light
so that can be registered as an image on the radio-
graphic film. Current approach for detection of image
in radiography technique is by Charge Couple Device
(CCD) camera. Both approaches, film or CCD still re-
quired converter materials to transform particle to the
light. The materials used as a converter in film ra-
diography is gadolinium, indium, dysprosium,lithium,
boron, rhodium, cadmium, samarinium, gold, and etc
[Hardt and H.Rottger, 1981]. The properties important
of converter materials for radiography and imaging us-
ing thermal neutron is given in Table 5.1.These ele-
ment widely used in the film neutron radiography tech-
nique. Currently, there are some composites materials
based on the element stated in Table 5.1.

Composite material used for converter screen in
neutron radiography usually contained Li and Gd. Typ-
ical example of this material is 6Li, F and Zn. The
process for neutron capture in a 6LiF/ZnS:Ag polymer
screen is by reaction of a thermal neutron with 6Li atom.
The reaction in the neutron capture process will results
in production of tritium and α (4He) as given in Equa-
tion 5.2. In addition to these particles, light at wave-
length 450 nm also emitted. This is the blue light and
it is detected by digital camera. The intensity of light
emitted from the conversion screen reflect the internal
distribution of object.

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