Small, Portable, Lightweight DT Neutron Generator for Use with NMIS Page: 3 of 7
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SMALL, PORTABLE, LIGHTWEIGHT DT NEUTRON GENERATOR
FOR USE WITH NMIS
J. Reichardt
MF Physics Corporation
5074 List Drive
Colorado Springs, Colorado 80919
J. T. Mihalczo, R. B. Oberer, L. G. Chiang, and J. K. Mattingly
Oak Ridge National Laboratory
P. O. Box 2008
Oak Ridge, Tennessee 37831-6004
ABSTRACT
The advantages of 14.1 MeV DT neutrons as an alternate source for the Nuclear Materials
Identification System (NMIS) are mainly increased sensitivity and accuracy which will extend
applications considerably as well as result in shorter measurement times for present applications.
Since NMIS requires a neutron source of ~ 5 x 106 n/sec, a small, lightweight (<30 lbs. including
the power supply and is 3-in.-OD pipe, - 4-ft. long) is under development at MF Physics
Corporation for the Oak Ridge National Laboratory (ORNL). By associated particle (alpha)
detectors, a cone of neutrons can be defined which is particularly useful for active neutron
interrogation of fissile materials in containers. After final test at ORNL, this DT neutron source
will be useful at the Y-12 National Security Complex for routine use with NMIS.
INTRODUCTION
NMIS is a time correlation technique that can be used passively for plutonium and in the active
mode with an external source to excite fissile material. It is useful for highly enriched uranium
(HEU) and plutonium. In an active measurement, the results of a passive measurement can be
separated for Pu. It is presently being used in the template matching mode at the Oak Ridge
Y-12 National Security Complex for confirmation of HEU weapons components upon receipt
and for inventory.2 For heavily shielded containers, like the AT400R, the 52Cf source neutrons
have difficulty penetrating the hydrogenous material of the container and the inserts to reach the
fissile material to induce fission. Another difficulty with 252Cf source is that the slow neutrons
from the source mix with the fast neutrons from the induced fission in the fissile material and
reduce sensitivity with distance from the object. Difficulty of operation of the DT source in the
1960s led to the use of 252Cf in an ionization chamber as a timed source of fission neutrons and
gamma rays.3 The reliability and portability of present DT sources makes it practical to replace
the 252Cf with a small-portable DT source. This has a variety of advantages over 252Cf and
makes NMIS more useful. This paper describes a small, portable DT neutron generator designed
by one the authors (Jack Reichardt) and states many of the improvements in NMIS such a source
would produce.
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Reichardt, J.; Mihalczo, J. T.; Oberer, R. B.; Chiang, L. G. & Mattingly, J. K. Small, Portable, Lightweight DT Neutron Generator for Use with NMIS, article, June 18, 2001; Tennessee. (https://digital.library.unt.edu/ark:/67531/metadc720272/m1/3/: accessed April 23, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.