Program - Brookhaven National Laboratory

extends the previous evaluation and includes comprehensive shell model analysis when possible. Evaluation
policies of experimental data and systematics will be discussed. Future plans for completion of the B(E2;0 + 1
→ 2 + 1 ) evaluation project will be outlined.
[1] S. Raman, C.W. Nestor and P. Tikkanen, Atomic Data and Nuclear Data Tables 78, 1 (2001).
PR 96
Measurements of High Energy Excited States and γ-rays of Fission Products with 4π
Clover Detector
Y. Shima, Graduate School of Engineering, Nagoya University, Japan. Y. Kojima, M. Shibata,
Radioisotope Research Center, Nagoya University, Japan. H. Hayashi, Institute of Health Biosciences,
The University of Tokushima, Japan. A. Taniguchi, Research Reactor Institute, Kyoto University, Japan.
Decay schemes are essential information in nuclear decay data for studies on nuclear physics and engineering.
To construct high energy excited states of fission products and γ-rays populating from the states is
important with respect to the decay heat evaluation in nuclear power plant, and also meaningful to know
the nuclear structure of neutron-rich nuclei. We have developed a clover detector which consists of four
large HPGe crystals (80 mm Φ x 90 mm) to measure β-decay energy (Qβ) [1]. Radioactive sources are
put into a through hole along the central axis of the detector. Therefore, we can measure the sources
with almost 4π solid angle. Energy signals from each Ge crystal are independently stored together with
the corresponding time information in an event-by-event mode. Two spectra, a singles and an add-back
spectrum, were obtained through an off-line sorting. In the singles spectrum, four individual spectra of
Ge crystals were summed and stored. Gamma-ray intensities are determined from the singles spectrum
using experimentally determined peak efficiencies with an accuracy of 5% [2]. In the add-back spectrum,
energy signals from the different crystals corresponding to coincident events were summed and stored.
High energy excited levels are assigned in the add-back spectrum compared with the singles one because
cascade γ-rays are identified as cross-over γ-rays. We have reported the level scheme of the fission product
147 Ce up to 3.5 MeV including newly identified 56 levels and 160 γ-rays [3]. 147 La isotopes, which are
the precursor of 147 Ce, were produced with the neutron-induced fission of 235 U, and separated using the
on-line mass separator installed at the Kyoto University Reactor. We have also measured γ-rays following
the β-decay of neutron-rich 145 Ba and 149 Ce, for which the excited levels up to 1.0 MeV were reported [4].
Note that 145 Ba is one of the radionuclides recommended to measure high energy excited states for precise
decay heat calculations [5]. We successfully observed the γ-rays and excited levels up to 3.0 and 2.5 MeV
in the daughter nuclei 145 La and 149 Pr, respectively. In this conference, we will report the decay schemes
of 145 Ba and 149 Ce as well as new findings of 147 La. This study is partially supported by “Study on nuclear
data by using a high intensity pulsed neutron source for advanced nuclear system” entrusted to Hokkaido
University by the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT).
[1] H. Hayashi et al., Abstract Book of the Int. Conf. Nucl. Data for Sci. and Technol. (ND2010), April
26-30, 2010, Jeju Island, Korea, 232. [2] Y. Shima et al., Proc. of the 2011 Symp. Nucl. Data, Nov. 16-17,
2011, Tokai, Japan, (in press). [3] Y. Shima et al., KURRI Prog. Rep. 2011, (in press). [4] Evaluated
Nuclear Structure Data File (ENSDF), http://nndc.bnl.gov/ensdf. [5] M.A. Kellett et al., NEA/WPEC
Volume 25, OECD, Nuclear Energy Agency Data Bank, Paris, France, 2007, ISBN 978-92-64-99034-0.
PR 97
Development Status and Perspectives on the CONRAD Evaluation Code
Pascal Archier, Cyrille De Saint Jean, Olivier Litaize, Gilles Noguère, Olivier Bouland, CEA, DEN,
DER, SPRC, LEPh, Cadarache, F-13108 Saint-Paul-lez-Durance, France.
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