Understanding Neutron Radiography

To make an informed choice of imaging system for a radiographic task we
must, ideally, have a detailed knowledge to the basic characteristics of a wide
range of recorders. These characteristics may be indentified as the
characteristic curve, neutron registration efficiency, and resolving power. The
screen/film recorders used for most neutron radiography are of two basic
types:
1) Those employing light-emitting intensifying screens, which have a
logarithmic response to neutron exposure and suffer from reciprocity-law
failure when exposure times are long.
2) Those employing charged particle-emitting screens, which have a linear
response and do not suffer reciprocity failure.
A simple analysis, particularly relevant in low-background conditions,
suggests that only when a linear-response recorder is used the sensitivity is
improved by increasing exposure. However, consideration of the effect of
natural statistics shows, that it is advantageous to increase exposures
whenever possible. 7.1.7.
Charlie Chong/ Fion Zhang
Practical.NR Chapter 7