RRFM 2009 Transactions - European Nuclear Society

ESTABLISHMENT OF A SINGLE-CRYSTAL FILTERED THERMAL
NEUTRON BEAM FACILITY FOR NEUTRON CAPTURE THERAPY
AT THE UNIVERSITY OF MISSOURI
John Brockman and Leslie P. Foyto
University of Missouri-Columbia Research Reactor
1513 Research Park Drive, Columbia, Missouri, 65211 – USA
David W. Nigg
Idaho National Laboratory
P.O Box 1625, Idaho Falls, Idaho, 83415 – USA
ABSTRACT
The University of Missouri Research Reactor (MURR), the highest-powered (10 MW th )
University-operated research reactor in the U.S., is a pressurized, reflected, openpool-type,
light-water moderated and cooled, heterogeneous system that provides a
broad range of analytical, radiographic, and irradiation services to the research
community and the commercial sector.
The International Institute of Nano and Molecular Medicine (IINMM) at the University
of Missouri (MU) has begun a new research effort to increase the catalogue of boron
delivery agents for boron neutron capture therapy (BNCT). In support of this effort the
MURR and Idaho National Laboratory (INL) have designed and constructed a new
thermal neutron beam facility for small animal BNCT. The thermal neutron beam
facility is designed around a 15.24 cm (6 in) diameter beam tube that extends radially
from the beryllium reflector. The design uses single-crystal silicon and bismuth
sections to produce a thermal neutron beam while minimizing the dose from reactor
gamma rays. Initial parameter studies and design calculations were preformed using
the computer codes MCNP5 and DORT.
The calculated and measured thermal neutron flux produced at the irradiation location
is 9.8 x 10 8 n/cm 2 -s, with a measured cadmium ratio (Au foils) of 136.8, indicating a
well-thermalized neutron spectrum with sufficient thermal neutron flux for a variety of
small animal BNCT studies. The calculated combined epithermal and fast neutron
kerma of the beam is approximately 1.0 x 10 -11 cGy-cm 2 , and the calculated incident
gamma kerma is approximately 4.0 x 10 -11 cGy-cm 2 .
I. Introduction
The International Institute for Nano and Molecular Medicine (IINMM) at the University of
Missouri (MU), Idaho National Laboratory (INL), and the University of Missouri Research
Reactor (MURR) are collaborating in a new research initiative to further the development of
improved boron neutron capture therapy (BNCT) agents and treatment protocols for a
broader array of tumor types.
Modern (post-1994) BNCT clinical trials differ from earlier trials largely because of the
availability of significantly improved, near-optimal, neutron sources and the implementation of
much more accurate computational and experimental dosimetry, including the required
analytical chemistry. In contrast, there have been essentially no improvements in the boron
containing targeting agents approved for human applications in the past 30 years. The
currently available, approved BNCT compounds, while offering some attractive features, are
still not optimal for the treatment of tumors of interest [1]. A key first step in the development
of new BNCT agents and treatment protocols has involved the design and construction of a
thermal neutron beam irradiation facility for cell and small-animal radiobiological research at
the MURR. In this paper we present the beamline design and construction with the results of
pertinent design calculations as well as initial neutronic performance measurements.
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