Understanding Neutron Radiography

The system provided a peak thermal neutron flux of about 10 9 neutrons per
square centimeter second (109 n∙cm -1 ∙s -1 ), two orders of magnitude less than
the reactor systems described above but sufficient for low throughput work
using 2 h exposure times and a relatively low beam collimation ratio.
Cyclotrons and radio frequency quadrupole accelerators are other candidates
for a potential custom designed in-house neutron radiographic system.
Neutron radiographic performance data have been reported for designs with a
variety of sizes, neutron yields and costs. For transportable systems much of
the development work has used sealed tube acceleration of deuterium tritium
mixtures. This can consist of a source head that is maneuverable with long
high tension cable linking it to the high voltage power supply and control unit
as illustrated (Fig. 9). The particular type shown yields a peak thermal neutron
flux of about 10 8 neutrons per square centimeter second with a tube operation
half life of about 200 h.
Charlie Chong/ Fion Zhang