7.5 Neutron Generators in Extreme Conditions
347
e main characteristic peaks of iron (UXO shell), titanium (ROV window),
carbon, and oxygen (TNT surrogate) can be observed. With respect to labora-
tory measurements of the sensor stability, underwater inspections were per-
formed with a neutron emission rate of 2.6 × 10
7
n/s instead of the maximum
5.8 × 10
7
n/s. Indeed, neutron interactions with the surrounding environment
strongly increase the gamma detector count rate and the associated random
background, the last rising with the square of neutron emission.
e relative proportion of carbon, oxygen, and nitrogen is commonly used
for explosive detection. In underwater inspection of thick iron shells, however,
the characteristic peaks of nitrogen ...