A new consideration has recently surfaced regarding neutron
sources for oil well logging:
homeland security /
nuclear non-proliferation issues.The
half lives for Cf252, AmBe, and AcBe in years are 2.645, 440, and 22,
respectively.Most sources are now AmBe
– AcBe has not caught on.(At present,
the program LVPM uses only AmBe as its neutron source.)Some Cf252 sources are in use, particularly
where small physical size and/or mechanical integrity are at a premium;
however, serious maintenance issues remain because of its short half-life.Sources like AmBe and AcBe with relatively
long half lives are prime candidates for dirty bomb manufacture and US regulations
for their possession, use, transport, and storage have tightened.Now, only the major players like Schlumberger
and Halliburton can afford to meet these new regulations and provide 24/7 guard
services to protect them.Delivery dates
have stretched out to 3 plus years.Particularly
dear are neutron sources with high neutron output (“19-Ci”).Cf252 is convenient for security gurus in
that it has a short half life of about 2.5 years.Neutron generators remain difficult to
manufacture and maintain and rarely work beyond 200 hours without maintenance/repair.