th  - 1987 - 51st ENC Conference

Monday - PM
NMR for the Detection of Explosives
William L. Rollwitz, Armando De Los Santos, George A. Matzkanin,
and J. DerwinKing
Southwest Research Institute
Division of Instrumentation and Space Research
6220 Culebra Road
San Antonio, TX 78213
High energy explosives have hydrogen NMR characteristics which are unique
and include very short values of T, and very long values of T,. These
characteristics cause problems when NMR is used to detect the presence of high
energy explosives in baggage, letters, packages, and soils when these items or
the NMR detection head are moving rapidly. The level crossing technique
(NMR/NQR) is used to reduce the long T, values of the explosives so that they
can be detected rapidly. By using the hydrogen NMR signal, the level-crossing
technique and other discrimination methods it is possible to detect the
presence of almost all explosives hidden in baggage, letters, packages and
soils using magnetic fields of less than 0.I Tesla and to discriminate rapidly
the hydrogen NMR signal caused by the explosives from the hydrogen NMR signal
from the other hydrogen containing materials that may be present in the
baggage, mail, packages and soils. It is even practical to consider portal-
type NMR detection heads to detect the presence of explosives hidden on or in
people.