Effects of the nuclear structure of fission fragments on the high-energy prompt fission -ray spectrum in U()

Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; Lguillon, R.; Ogawa, Tatsuhiko; Soldner, T.*; Kster, U.*; Pollitt, A.*; Hambsch, F.-J.*; et al.

Physical Review C, 100(4), p.044610_1 - 044610_7, 2019/10

https://doi.org/10.1103/PhysRevC.100.044610

A New detector system for the measurement of high-energy prompt -rays for low-energy neutron induced fission

Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; Lguillon, R.*; Ogawa, Tatsuhiko; Soldner, T.*; Hambsch, F.-J.*; Ache, M.*; Astier, A.*; et al.

Nuclear Instruments and Methods in Physics Research A, 906, p.88 - 96, 2018/10

https://doi.org/10.1016/j.nima.2018.07.055

We have developed a new setup to measure prompt fission -ray spectra in neutron induced fission up to energies sufficient to reveal the structure associated with giant dipole resonances of fission fragments. The setup consists of multi-wire proportional counters, to detect both fission fragments in coincidence, and two large volume (101.6 mm in diameter and 127.0 mm in length) LaBr(Ce) scintillators, to measure the -rays. The setup was used to obtain the prompt fission -ray spectrum for thermal neutron induced fission of U at the PF1B cold-neutron beam facility of the Institut Laue-Langevin, Grenoble, France. We have successfully measured the -ray spectrum up to energies of about 20 MeV, what extends the currently known -ray spectrum limit to higher energies by approximately a factor of two.

EXILL; A High-efficiency, high-resolution setup for -spectroscopy at an intense cold neutron beam facility

Jentschel, M.*; Blanc, A.*; de France, G.*; Kster, U.*; Leoni, S.*; Mutti, P.*; Simpson, G.*; Soldner, T.*; Ur, C.*; Urban, W.*; et al.

Journal of Instrumentation (Internet), 12(11), p.P11003_1 - P11003_33, 2017/11

https://doi.org/10.1088/1748-0221/12/11/P11003

Measurement of high-energy prompt -rays from neutron induced fission of U-235

Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; Lguillon, R.; Ogawa, Tatsuhiko; Soldner, T.*; Hambsch, F.-J.*; Astier, A.*; Pollitt, A.*; et al.

EPJ Web of Conferences, 146, p.04036_1 - 04036_4, 2017/09

https://doi.org/10.1051/epjconf/201714604036

The measurement of the prompt fission -ray spectrum (PFGS) is quite important to study the de-excitation process of neutron-rich fission fragments as well as to generate data required to design a generation-IV reactors. The PFGS measured for spontaneous fission of Cf shows a broad hump at energies more than 8 MeV. This is interpreted as a giant dipole resonance (GDR) of the fragments centered around 15 MeV. To understand how the GDR is populated in the fission process, one needs to measure the PFGS for the reactions with the mass yields different from the spontaneous fission of Cf, such as (n,f). The measurements of the PFGS for (n,f), however, are limited less than 9 MeV even in the recent experiment. This prompts us to make a new measurement to extend the know PFGS up to 20 MeV. The measurement has been carried out at the PF1B beam line of Institut Laue-Langevin. In this contribution we will present the results obtained the measurement.

Fission fragments mass distributions of nuclei populated by the multinucleon transfer channels of the O + Th reaction

Lguillon, R.; Nishio, Katsuhisa; Hirose, Kentaro; Makii, Hiroyuki; Nishinaka, Ichiro*; Orlandi, R.; Tsukada, Kazuaki; Smallcombe, J.*; Chiba, Satoshi*; Aritomo, Yoshihiro*; et al.

Physics Letters B, 761, p.125 - 130, 2016/10

https://doi.org/10.1016/j.physletb.2016.08.010

Multiple triaxial bands in Nd

Petrache, C. M.*; Ragnarsson, I.*; Ma, H.-L.*; Lguillon, R.; Zerrouki, T.*; Bazzacco, D.*; Lunardi, S.*

Physical Review C, 91(2), p.024302_1 - 024302_16, 2015/02

https://doi.org/10.1103/PhysRevC.91.024302

High spin structure of S and the proton-neutron coupling of intruder states

Mason, P.*; Mrginean, N.*; Lenzi, S. M.*; Ionescu-Bujor, M.*; Della Vedova, F.*; Napoli, D. R.*; Otsuka, Takaharu*; Utsuno, Yutaka; Nowacki, F.*; Axiotis, M.*; et al.

Physical Review C, 71(1), p.014316_1 - 014316_8, 2005/01

https://doi.org/10.1103/PhysRevC.71.014316

no abstracts in English

Measurement of high energy -ray spectrum accompanied by neutron induced fission of U

Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; Ogawa, Tatsuhiko; Soldner, T.*; Hambsch, F.-J.*; Frost, R.*; Tsekhanovich, I.*; Petrache, C. M.*

no journal, , 

The Japanese government has a plan to remove the melted reactor fuel for the full deconstruction of Fukushima I Nuclear Power Plants. The removal of the fuel must be carried out without reaching the criticality of the fuel. However, it is quite difficult to monitor the increased fission rate due to the background -rays from the fission products in the fuel. Here we are proposing to develop a system based on the use of the high energy -rays accompanied by fission. In order to design the system, it is essential to know the spectrum of prompt fission -rays up to more than 7 MeV for U(n,f) reaction. However, no data are available in the -ray energy range larger than 7 MeV. This prompted us to make a new measurement to extend the known prompt -ray energy spectrum up to 20 MeV. The measurement has been carried out at the PF1b beam line of the Institut Laue-Langevin. In this contribution, we will present the results obtained the measurement.

Surrogate reactions for neutron-induced fission reaction and capture reaction by heavy ion transfer reactions

Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; Yan, S. Q.*; Lguillon, R.; Smallcombe, J.*; Vermeulen, M. J.; Nishinaka, Ichiro*; Tsukada, Kazuaki; et al.

no journal, , 

A project of the fission data measurement as well as the measurement of the neutron capture cross sections, using a surrogate method based on multi-nucleon transfer reactions, is running at JAEA. We have constructed appatus consists of a fission setup including four position-sensitive multi-wire proportional counters (MWPCs) to detect fission fragments and a capture setup containing two anti-Compton LaBr(Ce) spectrometers to measure the rays from the populated compound nuclei. Both setups contain a Si E-E detector to detect outgoing projectile-like particles by which we can identify the populated compound nuclei. We also placed 33 scintillators around the fission setup to detect fission neutrons in coincidence with the fission fragments. The measurements was carried out at the JAEA-Tokai tandem accelerator facility. In this contribution, we will present our results on neutron-induced fission and neutron capture cross sections by using the surrogate method.

Measurement of high-energy prompt fission rays in U(n,f)

Ogawa, Tatsuhiko; Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; Lguillon, R.*; Soldner, T.*; Hambsch, F.-J.*; Ache, M.*; Astier, A.*; et al.

no journal, , 

Measurement of -rays emitted from fission of actinide has been conducted for radiation transport analysis in reactors, safety of spent fuel, and fundamental nuclear physics. In earlier studies, -rays up to 8 MeV were measured because they are those emitted by fission fragments at excited states. According to some theoretical studies, however, some fission fragments have excitation energy up to 20 MeV and they emit -rays above 8 MeV. In this study, the -rays produced by fission of U induced by thermal neutrons were measured with LaBr scintillators at the high-flux reactor in the Institut Laue Langevin. The obtained -ray spectrum agreed with the earlier measurement below 8 MeV, forms a bump above 10 MeV, and smoothly continued up to 20 MeV. The measurement in this study clarified the -ray energy spectrum attributed to fission reactions up to 20 MeV in case of U(n,f).