Program - Brookhaven National Laboratory

from non 1/v behavior of nuclei. Moreover, the parallel use of neutron imaging and prompt gamma-ray
measurements of the same object gives a unique possibility for target characterization. The influence of
the energy and spatial distributions of the beam on the measurements of partial gamma-ray production
cross sections as well as on the total neutron capture cross sections will be discussed. The experimental
stations are open for the user community. For European users, in the nuclear data field, support can be
obtained from the EU FP7 ERINDA project (http://www.erinda.org/). Other users can make proposals
on bilateral agreement bases. * This work is supported by the NAP VENEUS OMFB 00184/2006 and the
NORMA 10 OMFB-00494/2010 projects.
[1] EFNUDAT - Slow and Resonance Neutrons. The 2nd EFNUDAT Workshop on Neutron Measurements,
Theory and Applications, 23-25 September 2009, ed. T. Belgya, 1-174. Budapest, Hungary: Institute of
Isotope, Hungarian Academy of Sciences (2010).
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New Method for Measurement of Neutron Detector Efficiency up to 20 MeV
N.V. Kornilov, S.M. Grimes, T.N. Massey, C.E. Brient, D. E. Carter, J.E. O’Donnell, K. W. Cooper
Department of Physics and Astronomy, Ohio University, Athens, OH 45701, USA
F.B. Bateman, A.D. Carlson
National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
R.C. Haight
Los Alamos Neutron Science Center, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
N. Boukharouba
Department of Physics, University of Guelma, Guelma 24000, Algeria
The efficiency of a neutron detector is an extremely important characteristic for successful experiments in
nuclear and neutron physics. This characteristic of the detector depends not only on scintillator properties
but includes strong influence on the detector environment and should be investigated experimentally as
well as by model calculations. For many fundamental measurements (like the angular distribution of (n,p)
scattering with an accuracy 1%) and applied tasks (such as measurements of standard neutron fields with
energies up to 20 MeV with accuracy 1-2%), the request for accuracy is very high. The realization of this
request is not a simple task. In this report we suggest a new method for the measurement of the neutron
detector efficiency. It is based on the obvious fact that the neutron yield from a symmetric reaction (one in
which the projectile and the target are identical) is the same for a forward angle θ, and the supplementary
back angle 180-θ, in the Center of Mass System, however the neutron energies at the corresponding angles
in the Laboratory System are different. Thus, the relative efficiency at two energies can be measured
directly. By changing the beam-energy, and analyzing reaction with excitation of the separate levels a
large set of efficiency ratios can be obtained. The 6 Li( 6 Li,n) is a very attractive candidate to cover the
energy range 1-20 MeV with input Li ion energy of 4-12 MeV. Starting from excitation of high energy levels
(neutron energy 2-8 MeV) we may move up to 20 MeV neutrons. The low energy range of the efficiency
may be estimated relative to the 252 Cf spontaneous fission neutron standard. In the report, we discuss the
method itself, and its application for the 6 Li( 6 Li,n), 12 C( 12 C,n), and D(d,n) reactions, and demonstrate
the results for a NE213 detector. This work is in support of the NIFFTE Fission TPC measurements.
Corresponding author: Thomas N. Massey
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