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Nakamura, Shoji; Kimura, Atsushi; Hales, B. P.; Iwamoto, Osamu; Shibahara, Yuji*; Uehara, Akihiro*; Fujii, Toshiyuki*
JAEA-Conf 2018-001, p.199 - 203, 2018/12
Study on cross-section measurements has been promoted for 
Cs among long-lived fission products in ImPACT Project. The feasibility study on 
Se sample preparation also has been conducted to measure its cross sections in future. During the feasibility study, we started the neutron-capture cross-section measurements of stable Se isotopes. This paper reports research progresses on preparation of a radioactive Cs sample, neutron irradiation experiments with the Cs sample, and cross-section measurements of stable Se isotopes.
Cs/
Cs isotopic ratio for samples used for neutron capture cross section measurement project by thermal ionization mass spectrometryShibahara, Yuji*; Uehara, Akihiro*; Fujii, Toshiyuki*; Nakamura, Shoji; Kimura, Atsushi; Hales, B. P.; Iwamoto, Osamu
JAEA-Conf 2018-001, p.205 - 210, 2018/12
In the ImPACT project, high-precision mass analysis was performed on a Cs standard solution for using Cs included in the standard solution as an impurity to measure the Cs cross-sections. A Cs standard solution of only 10Bq (pg order) was analyzed, and the isotope ratio of Cs and Cs was obtained with an accuracy of 0.5%.
Cs as a part of the ImPACT projectHales, B. P.; Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu
JAEA-Conf 2017-001, p.199 - 203, 2018/01
Nakamura, Shoji; Kimura, Atsushi; Hales, B. P.; Iwamoto, Osamu; Tsubata, Yasuhiro; Matsumura, Tatsuro; Shibahara, Yuji*; Uehara, Akihiro*; Fujii, Toshiyuki*
JAEA-Conf 2017-001, p.15 - 22, 2018/01
Neutron nuclear data of long lived fission products (LLFPs) have been required as basic data for the technology of reduce environmental impact involved in high level radioactive wastes (HLW). The innovative large project called by "Impusing Paradigm Change through Disruptive Technologies Program: ImPACT" have been started from October, 2014. In the ImPACT project, some research groups of JAEA engaged in the Project No.2 (Nuclear Reaction Data Measurements), and have started measurements of neutron capture cross-section at J-PARC/MLF/ANNRI. In our research, we selected cesium-135 (Cs) nuclide (half life: 2.3
10
yr.) among LLFPs in the HLW, and decided to measure the neutron capture cross-sections of Cs. When measurement, the Cs sample might contained cecium-137 (Cs) as impurities because it's impossible to chemically separate each other. To measure the cross-sections of Cs, there should be also needed to know the cross-sections of Cs. In this work, sample maintenance also has been examined especially for selen-79 (Se) nuclide among LLFPs having difficulty in sample preparations. In this oral session, the outline of our research project will be presented together with a research motivation, situations of past reported data, total schedules, progress, future plans, and some of high light data for neutron capture cross-section measurements.
Nakamura, Shoji; Shibahara, Yuji*; Uehara, Akihiro*; Fujii, Toshiyuki*; Kimura, Atsushi; Hales, B. P.; Iwamoto, Osamu
KURRI Progress Report 2016, P. 66, 2017/07
In the ImPACT project, high-precision mass analysis was performed on a Cs standard solution for using Cs included in the standard solution as an impurity to measure the Cs cross-sections. A Cs standard solution of only 10Bq (pg order) was analyzed, and the isotope ratio of Cs and Cs was obtained with an accuracy of 0.5%.
Cs(n,
) cross-section using a New DAQ System at ANNRIHales, B. P.; Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu
J-PARC 17-07; J-PARC MLF Annual Report 2016, p.88 - 89, 2017/03
Nakamura, Shoji; Kimura, Atsushi; Hales, B. P.; Iwamoto, Osamu; Tsubata, Yasuhiro; Matsumura, Tatsuro
no journal, ,
As a part of research items on ImPACT Project, nuclear data research group of JAEA has performed the research on neutron capture cross-section measurements of Cs isotopes, especially Cs-135. This presentation gives an outline of research plans and their progress.
CsHales, B. P.; Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu
no journal, ,
no abstracts in English
Cs neutron-capture cross-section as part of the ImPACT projectHales, B. P.; Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu
no journal, ,
There is currently a plan to measure the neutron-capture cross-section of Cs (half-life 2.3 million years), using the neutron beam at the Materials and Life science Facility (MLF) at J-PARC. In the course of measuring Cs, it is unavoidable that Cs (stable) will be an impurity within the sample. In order to derive high-quality Cs data, it is necessary to also measure Cs. We have measured the neutron-capture cross-section of Cs using ANNRI at the MLF at J-PARC, in the energy region from thermal to 1.5 keV, via the time-of-flight method. This measurement has better statistics and covers a wider energy range than previous measurements of Cs. Additionally, we have confirmed the misassignment of various resonances from previous experiments.
Cs using ANNRI in the MLF at J-PARCHales, B. P.; Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu
no journal, ,
As part of the ImPACT project, it is currently planned to measure the neutron cross-section of Cs (half-life 
y), a long-lived fission product (LLFP), via neutron time-of-flight (TOF) method using ANNRI in the Material and Life science Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC). Cs (natural Cs, stable) exists as a contaminant in the Cs sample. To make an accurate measurement of Cs, accurate data of the Cs cross-section is required. We have measured the neutron cross-section in the thermal and epithermal energy regions. We will report on the measured cross-section data, resonances, and our methodology.
cross-section of long-lived fission products as part of the ImPACT ProjectHales, B. P.; Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu
no journal, ,
Nakamura, Shoji; Kimura, Atsushi; Hales, B. P.; Iwamoto, Osamu; Shibahara, Yuji*; Uehara, Akihiro*; Fujii, Toshiyuki*
no journal, ,
This presentation gives some progress about neutron capture cross section measurements of long-lived fission products, especially Cecium-135 under the ImPACT Project.
Hales, B. P.; Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu
no journal, ,
We have measured the neutron-capture cross-sections of various Se isotopes (
Se) via neutron time-of-flight (nTOF) method, using J-PARC/MLF/ANNRI, up to the incident neutron energy range of 1.5 keV. We are currently considering measuring the long-lived fission product (LLFP) Se (half-life: 330,000 years), a component of nuclear waste, using J-PARC/MLF/ANNRI. It is thought to be very difficult to remove stable selenium isotopes from our Se sample. In order to increase the quality of the data in a Se measurement, data for stable selenium isotopes are necessary. In this presentation, we will presently mainly on our findings in regareds to 
.Se
Hales, B. P.; Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu
no journal, ,
It is necessary to account for detector and data acquisition system dead-time in time-dependent radiation detection experiments. Until now, the paralyzable and non-paralyzable models, in which an event occurring in the detector causes the detector to be unable to detect another event for a short period of time. (That is to say, deadtime occurs after an event). However, during a time-of-flight experiment with the new DAQ system for the Ge detector at J-PARC/MLF/ANNRI, we have found a phenomenon which is entirely unexplainable by these models. In this talk, we will discuss this new type of dead-time, its causes, and how to correct for it.
Nakamura, Shoji; Kimura, Atsushi; Hales, B. P.; Iwamoto, Osamu; Shibahara, Yuji*; Uehara, Akihiro*; Fujii, Toshiyuki*
no journal, ,
Under the ImPACT project, the neutron capture cross-section measurements of Cs-135 among the long-lived fission products have been performed at J-PARC and Kyoto University. In this presentation, the measurements of energy-dependent neutron capture cross-section for Cs-135 will be reported, and the neutron irradiations of Cs-135 at the KUR will be also presented.
