Advanced fissile neutron detection system and method

A fissile neutron detection system for detecting incident fissile neutrons, said fissile neutron detection system, comprising:

• an ionizing thermal neutron detector arrangement including an inner peripheral shape that at least substantially surrounds a moderator region for detecting thermal neutrons that exit the moderator region but is at least generally transparent to the incident fissile neutrons, the ionizing thermal neutron detector arrangement further including at least one group of ionizing thermal neutron detectors with the ionizing thermal neutron detectors of each group in a side-by-side relationship and spaced apart in the side-by-side relationship to form a gap between adjacent ones of the ionizing thermal neutron detectors;
• at least one moderator disposed within the moderator region for converting the incident fissile neutrons in the moderator region to thermal neutrons which exit the moderator region to then enter the ionizing thermal neutron detector arrangement for detection of at least some of the thermal neutrons to produce an electrical current as a fissile neutron detection system output with the moderator having an outer peripheral shape that is at least generally complementary to said inner peripheral shape and the arrangement includes lateral extents such that any given dimension that bisects the lateral extents includes a length that is greater than any thickness of the moderator transverse to the lateral extents;
• and
• at least one external moderator disposed outside the moderator region proximate to the ionizing thermal neutron detector arrangement.