Program - Brookhaven National Laboratory

definitive results of the measurements of the isotopic and mass fission yields for the 233U(nth,f) reaction
performed at the Lohengrin recoil mass spectrometer of the ILL. The spectrometer separates the fission
products according to their mass over ionic charge and kinetic energy over ionic charge. The mass yields
were obtained with an ionisation chamber after separation by the spectrometer. The isotopic yields were
determined with a different set-up composed of two high purity Germanium clover detectors that was placed
subsequent to the spectrometer. An innovative analysis method developed for the Lohengrin spectrometer
will be presented, where the final results happen to be independant from the previous evaluations, which
is usually not the case. To provide experimental covariance data, detailed consideration has been given to
the uncertainties and their correlations during the various experimental phases of this work.
Corresponding author: C. Sage
PD 8 5:45 PM
Precision Velocity Measurements of Fission Fragments Using the SPIDER Detector 1
C.W. Arnold, F.K. Tovesson, K. Meierbachtol, A.B. Laptev, T.A. Bredeweg, M. Jandel, R.O. Nelson,
M.C. White
Los Alamos National Laboratory, Los Alamos, NM 87545, USA
Unit mass resolution of fragments from neutron-induced fission may be achieved if a fragment’s energy
and velocity can be measured to high enough precision. The SPIDER detector measures position and
TOF using a system of thin carbon foils, electrostatic mirrors, microchannel plates, delay-line anodes, and
a fast TDC to achieve the requisite precision for velocity. Tests have been conducted using spontaneous
fission( 252 Cf) and alpha ( 229 Th) sources. To date, timing resolution of 300 ps (FWHM) has been achieved
corresponding to < 1% uncertainty in velocity measurements of fission fragments over a 50 cm flight path
length. Optimization of the position and TOF portion of the SPIDER detector will improve the timing
resolution. The most recent results will be presented and discussed. 1 Work supported by grants for LDRD
Project 20110037DR.
Session PE Benchmark and Testing
Thursday March 7, 2013
Room: Central Park West at 3:30 PM
PE 1 3:30 PM
Benchmark Calculations for Reflector Effect in Fast Cores by Using the Latest Evaluated
Nuclear Data Libraries
Masahiro Fukushima, Makoto Ishikawa, Kazuyuki Numata, Tomoyuki Jin And Teruhiko Kugo
Japan Atomic Energy Agency (JAEA)
The impact of the scattering angular distributions (µ-bar) and scattering cross-sections on neutron multiplication
factor (keff ) values has been recently pointed out for small fast reactor cores with reflector.
In Working Party on International Nuclear Data Evaluation Cooperation (WPEC) of OECD/NEA, the
subgroup 35 (Scattering Angular Distribution in the Fast Energy) has started their activities in 2012.
Integral benchmark tests in which the scattering data play important role are necessary for evaluation for
these. In the present paper, benchmark calculations for reflector effects in fast cores are presented out by
using the latest major evaluated nuclear data libraries, JENDL-4.0, ENDF/B-VII.1 and JEFF-3.1.2. In
the benchmark tests, the FCA X-1 and -2 cores, the Joyo Mk-I and -II cores, the ZPR-3/53, -3/54 and the
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