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Journal Articles

Study of neutron capture reactions using the 4$$pi$$ Ge spectrometer

Harada, Hideo; Goko, Shinji*; Kimura, Atsushi; Ota, Masayuki*; Oshima, Masumi; Kitatani, Fumito; Toh, Yosuke; Furutaka, Kazuyoshi; Kin, Tadahiro; Koizumi, Mitsuo; et al.

Journal of the Korean Physical Society, 59(2), p.1547 - 1552, 2011/08

 Times Cited Count:7 Percentile:48.39(Physics, Multidisciplinary)

For the improvement of the accuracy on the neutron capture cross sections, a 4$$pi$$ Ge spectrometer was developed. The 4$$pi$$ Ge spectrometer is a unique tool due to its superior energy resolution for studying properties on neutron capture reactions, not only capture cross sections but also resonance identification, $$gamma$$-ray intensity distribution, and spin-parity assignment. For example, its performance on the resonance identification was demonstrated using a $$^{rm nat}$$Ag sample. On the measurement of a $$gamma$$-ray intensity distribution for each resonance, the results of $$^{238}$$U will be shown. Using the 4$$pi$$ Ge spectrometer, the measurements of neutron capture cross sections were started at the J-PARC/MLF/ANNRI. The preliminary results on the measurements of neutron capture cross sections will be discussed mainly based on measurements of neutron capture cross sections for $$^{241}$$Am, together with related techniques.

Journal Articles

$$E1$$ and $$E2$$ cross sections of the $$^{12}$$C$$(alpha,gamma_{0})^{16}$$O reaction using pulsed $$alpha$$ beams

Makii, Hiroyuki; Nagai, Yasuki*; Shima, Tatsushi*; Segawa, Mariko; Mishima, Kenji*; Ueda, Hitoshi*; Igashira, Masayuki*; Osaki, Toshiro*

Physical Review C, 80(6), p.065802_1 - 065802_16, 2009/10

 Times Cited Count:26 Percentile:16.39(Physics, Nuclear)

We measured the $$gamma$$-ray angular distribution from $$^{12}$$C$$(alpha,gamma_{0})^{16}$$O to the ground state of $$^{16}$$O using a pulsed $$alpha$$ beam at $$E_{rm eff} = 1.6$$ and 1.4 MeV. True events of $$^{12}$$C$$(alpha,gamma_{0})^{16}$$O were discriminated from background events due to neutrons from $$^{13}$$C($$alpha,n$$)$$^{16}$$O with a time-of-flight method. The obtained $$gamma$$-ray spectrum with anti-Compton NaI(Tl) spectrometers showed a characteristic line shape from $$^{12}$$C$$(alpha,gamma_{0})^{16}$$O: the Doppler broadening and energy loss of $$alpha$$ particles in $$^{12}$$C targets. The astrophysical S factors for $$E1$$ and $$E2$$, $$S_{E1}(gamma_{0}:E_{rm eff})$$ and $$S_{E2}(gamma_{0}:E_{rm eff})$$, derived from the present cross sections are in excellent agreement with the values derived by $$R$$-matrix calculation of the $$beta$$-delayed $$alpha$$ spectrum of $$^{16}$$N, and by using the asymptotic normalization constant in the $$R$$-matrix fit.

Journal Articles

Performance of a 4$$pi$$ Ge spectrometer for neutron capture cross section measurements

Oshima, Masumi; Hori, Junichi*; Harada, Hideo; Furutaka, Kazuyoshi; Koizumi, Mitsuo; Kitatani, Fumito; Toh, Yosuke; Kimura, Atsushi; Nakamura, Shoji; Igashira, Masayuki; et al.

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.1, p.603 - 606, 2008/05

Neutron capture cross sections of minor actinides and long-lived fission products are important for the R&D of innovative nuclear reactors. However, those data are rather poor both in quality and in quantity at present. Thus, we have started projects for neutron cross section measurements. We will construct an innovative $$gamma$$-ray spectrometer consisting of Ge crystals and BGO shields. The neutron cross section measurements will be done at KUR linac and JAEA JRR-3M facilities, which will be extended at the high-intensity neutron source at J-PARC.

Journal Articles

Role of multiparticle-multihole states in $$^{18,19}$$O in thermal neutron capture of $$^{18}$$O

Nagai, Yasuki*; Segawa, Mariko; Osaki, Toshiro*; Matsue, Hideaki; Muto, Kazuo*

Physical Review C, 76(5), p.051301_1 - 051301_6, 2007/11

 Times Cited Count:9 Percentile:40.66(Physics, Nuclear)

The primary $$E$$1 $$gamma$$-ray transition strength from the thermal neutron capture of $$^{18}$$O to the 3/2$$^{-}$$ state, 18 keV below the neutron threshold of $$^{19}$$O, was found to be about two hundred thousand times stronger than that to the 1/2$$^{-}$$ excited state, 729 keV below the threshold. In addition, the $$E$$1 strength from the 3/2$$^{-}$$ state leading to the 3/2$$^{+}$$ state with three ($$d$$$$_{5/2}$$)$$^{3}$$ neutrons was six times stronger than that to the 5/2$$^{+}$$ ground state with a single ($$d$$$$_{5/2}$$) neutron. These anomalous $$gamma$$-ray decay patterns give the first clear experimental evidence for the predicted property of the 3/2$$^{-}$$ state as mainly having a one-hole-four-particle configuration. Unique features of the $$^{18}$$O ground state with a two-hole-four-particle configuration and of the 3/2$$^{+}$$ state combined with a discrete prompt $$gamma$$-ray spectroscopy following the thermal neutron capture of $$^{18}$$O enabled us to exclusively identify the configuration of the 3/2$$^{-}$$ state.

Journal Articles

Minor actinide neutron capture cross-section measurements with a 4$$pi$$ Ge spectrometer

Koizumi, Mitsuo; Osa, Akihiko; Toh, Yosuke; Kimura, Atsushi; Mizumoto, Motoharu; Oshima, Masumi; Igashira, Masayuki*; Osaki, Toshiro*; Harada, Hideo*; Furutaka, Kazuyoshi*; et al.

Nuclear Instruments and Methods in Physics Research A, 562(2), p.767 - 770, 2006/06

 Times Cited Count:6 Percentile:54.09(Instruments & Instrumentation)

In order to measure the neutron capture cross section of minor actinides, we have proposed the use of a 4$$pi$$ Ge spectrometer. A Time-of-Flight neutron beam line for the experiment has been constructed at the KURRI electron LINAC. The assembling of the 4$$pi$$ Ge spectrometer is in progress. We are also developing a new data acquisition system based on a digital processing technique.

Journal Articles

Distortion of pulse-height spectra of neutron capture $$gamma$$ rays

Laptev, A.; Harada, Hideo; Nakamura, Shoji; Hori, Junichi*; Igashira, Masayuki*; Osaki, Toshiro*; Ogama, Kazuya*

AIP Conference Proceedings 819, p.402 - 406, 2006/03

None

JAEA Reports

Study on neutron capture cross sections of long-lived fission products

Igashira, Masayuki*; Osaki, Toshiro*; Nagai, Yasuki*; Yamana, Hajimu*; Fujii, Toshiyuki*; Takamiya, Koichi*; Harada, Hideo; Furutaka, Kazuyoshi; Nakamura, Shoji

JNC-TY8400 2005-009, 186 Pages, 2005/09

JNC-TY8400-2005-009.pdf:14.33MB

Accurate fast-neutron capture cross sections of long-lived fission products (LLFPs) are indispensable for the R&D of nuclear transmutation systems which utilize the fast-neutron capture reaction. The accuracy of those cross section data contained nuclear data libraries are, however, quite inadequate. Therefore, accurate experimental data on those cross sections are necessary as the basic data usefule for the evaluation of capture cross sections of LLFPs. The final goal of the present study is to obtain the results with the errors from 5 to 10% fore the fast-neutron capture cross sections of $$^{99}$$Tc and tentative results with the errors of about 10% for those of $$^{93}$$Zr, using the electron linear accelerator based neutron source at the Oak Ridege National Laboratory. For this goal, the four research items were executed: (1) the separation, purification and analysis of LLFP samples, (2) the improvement of weighting function of $$gamma$$-ray detector, (3) the measurement of fast-neutron capture cross sections of impurity isotopes in LLFP samples, and (4) the measurement of fast-neutron capture cross sections of $$^{99}$$Tc and $$^{93}$$Zr. The final goal was not reached due to the long-term trouble of the electron linear accelerator, but sufficient results were obtained for the other items. In particular, the present results for the capture cross sections and capture $$gamma$$-ray spectra of $$^{90,91,92,94}$$Zr wer important nuclear data for the R&D of nuclear transmutation systems.

Journal Articles

Measurements of neutron-capture cross sections of radioactive nuclides through high-energy $$gamma$$-ray spectroscopic studies

Furutaka, Kazuyoshi; Harada, Hideo; Nakamura, Shoji; Sakane, Hitoshi; Yamana, Hajimu*; Fujii, Toshiyuki*; Yamamoto, Shuji*; Hori, Junichi*; Igashira, Masayuki*; Osaki, Toshiro*; et al.

KURRI Progress Report 2004, P. 16, 2005/09

This report describes the studies done through spectroscopic method of high-energy $$gamma$$ ray to determine neutron capture cross sections of radioactive nuclides, in FY2004 at the Research Reactor Institute, Kyoto University. The following three items are described. (1) Development of a method to determine thermal neutron capture cross sections by prompt $$gamma$$-ray measurements, (2) Evaluation of a large BGO detector system as a total-energy detector, and (3) neutron capture cross-section measurements by TOF method.

Journal Articles

Response of a high-resolution high-energy photon spectrometer (HHS) to monochromatic high-energy $$gamma$$ rays

Harada, Hideo; Furutaka, Kazuyoshi; Nakamura, Shoji; Osaka, Koji*; Akimune, Hidetoshi*; Utsunomiya, Hiroaki*; Osaki, Toshiro*; Igashira, Masayuki*

Nuclear Instruments and Methods in Physics Research A, 554(1-3), p.306 - 313, 2005/08

 Times Cited Count:19 Percentile:20.58(Instruments & Instrumentation)

The response function of a high-resolution high-energy photon spectrometer (HHS), consisting of a twin Ge detector and BGO (Bi$$_{3}$$Ge$$_{4}$$O$$_{12}$$) anti-coincidence shields, has been measured to 10.763 MeV monochromatic $$gamma$$-rays generated via an$$^{27}$$Al(p,$$gamma$$)$$^{28}$$Si reaction. The measured response functions both with and without anti-coincidence were compared with the calculations by Monte Carlo simulations, in which the pulse-height degradation effect associated with a surface channel has been taken into account. Excellent agreements were obtained between the measured response functions and the simulations by introducing two fitting parameters for the BGO shields.

Journal Articles

Simulation of 4$$pi$$ Ge spectrometer by Geant4

Goto, Jun; Sugawara, Masahiko*; Oshima, Masumi; Toh, Yosuke; Kimura, Atsushi; Osa, Akihiko; Koizumi, Mitsuo; Mizumoto, Motoharu; Osaki, Toshiro*; Igashira, Masayuki*; et al.

AIP Conference Proceedings 769, p.788 - 791, 2005/05

no abstracts in English

Journal Articles

Baseline distortion effect on $$gamma$$-ray pulse-height spectra in neutron capture experiments

Laptev, A.; Harada, Hideo; Nakamura, Shoji; Hori, Junichi*; Igashira, Masayuki*; Osaki, Toshiro*; Ogama, Kazuya*

Nuclear Instruments and Methods in Physics Research A, 543(2-3), p.502 - 508, 2005/00

 Times Cited Count:5 Percentile:57.11(Instruments & Instrumentation)

A baseline distortion effect due to gamma-flash at neutron time-of-flight measureemnt using a pulse neutron source has been investigated.

Journal Articles

The Response of the High-Resolution High-Energy Photon Spectrometer II

Osaka, Koji*; Utsunomiya, Hiroaki*; Akimune, Hidetoshi*; Osaki, Toshiro*; Igashira, Masayuki*; Furutaka, Kazuyoshi; Harada, Hideo

KEK Proceedings 2003-15, p.37 - 44, 2004/02

We report the response of the high-resolution high-energy photon spectrometer to 10.7 MeV $$gamma$$ rays produced in the Al-27(p,$$gamma$$)Si-28 reaction with and without the Compton suppression mode. A tail of the full-energy peak and an enhancement of the low-energy component were investigated in detail with a Cs-137 standard source. EGS4 simulations of these phenomena were made assuming imperfect charge collection due to the effect of trapping/detrapping charge carriers by defects or trapping centers of a coaxial HPGe detector. A preliminary result is presented.

JAEA Reports

Research on the behavior of polonium produced in lead-bismuth eutectic irradiated with neutrons, JAERI's nuclear research promotion program, H10-026 (Contract research)

Sekimoto, Hiroshi*; Igashira, Masayuki*; Yano, Toyohiko*; Obara, Toru*; Osaki, Toshiro*

JAERI-Tech 2002-008, 58 Pages, 2002/03

JAERI-Tech-2002-008.pdf:3.6MB

no abstracts in English

Journal Articles

High-Energy Gamma-Ray Spectroscopy by High-Resolution Spectrometer:HHS

Furutaka, Kazuyoshi; Harada, Hideo; Sugimoto, Shigetoshi*; Osaka, Koji*; Igashira, Masayuki*; Osaki, Toshiro*

Proceedings of the Eleventh International Symposium "Capture Gamma-Ray Spectroscopy and Related Topics" (CGS11), 0 Pages, 2002/00

None

JAEA Reports

Maxwellian-averaged cross sections calculated from JENDL-3.2

Nakagawa, Tsuneo; Chiba, Satoshi; Osaki, Toshiro*; Igashira, Masayuki*

JAERI-Research 2000-002, p.93 - 0, 2000/02

JAERI-Research-2000-002.pdf:4.41MB

no abstracts in English

Oral presentation

Development of 4-$$pi$$ Ge spectrometer for neutron capture cross section measurement

Toh, Yosuke; Oshima, Masumi; Koizumi, Mitsuo; Kimura, Atsushi; Harada, Hideo; Furutaka, Kazuyoshi; Kitatani, Fumito; Nakamura, Shoji; Mizumoto, Motoharu; Goto, Jun*; et al.

no journal, , 

no abstracts in English

Oral presentation

$$sigma$$$$_{E2}$$ and $$sigma$$$$_{E1}$$ of the $$^{12}$$C($$alpha$$, $$gamma$$)$$^{16}$$O reaction obtained at E$$_{cm}$$ = 1.6 and 1.4 MeV

Makii, Hiroyuki; Nagai, Yasuki*; Shima, Tatsushi*; Segawa, Mariko; Ueda, Hitoshi*; Masaki, Tomohiro*; Mishima, Kenji*; Igashira, Masayuki*; Osaki, Toshiro*

no journal, , 

no abstracts in English

Oral presentation

Neutron induced reaction and Re/Os cosmochronometer, 3

Segawa, Mariko; Nagai, Yasuki*; Masaki, Tomohiro*; Shima, Tatsushi*; Makii, Hiroyuki; Mishima, Kenji*; Ueda, Hitoshi*; Temma, Yasuyuki*; Igashira, Masayuki*; Osaki, Toshiro*; et al.

no journal, , 

no abstracts in English

Oral presentation

Preliminary measurements of $$^{237}$$Np neutron capture cross section

Mizumoto, Motoharu; Oshima, Masumi; Koizumi, Mitsuo; Toh, Yosuke; Kimura, Atsushi; Harada, Hideo; Furutaka, Kazuyoshi; Kitatani, Fumito; Nakamura, Shoji; Igashira, Masayuki*; et al.

no journal, , 

Neutron capture cross section measurements of minor actinide nuclei have been carried out using a 4 $$pi$$ Ge spectrometer. In the meeting, preliminary results of $$^{237}$$Np capture cross sections measured at the KUR electron linac TOF facility are reported.

Oral presentation

Performance of 4$$pi$$ Ge spectrometer

Oshima, Masumi; Toh, Yosuke; Koizumi, Mitsuo; Kimura, Atsushi; Harada, Hideo; Furutaka, Kazuyoshi; Kitatani, Fumito; Nakamura, Shoji; Mizumoto, Motoharu; Goto, Jun*; et al.

no journal, , 

We have constructed a 4$$pi$$ Ge spectrometer for neutron capture cross section measurements. It was set at the JAEA research reactor, JRR-3M, and the Kyoto university electron linear accelerator facilities. The results of $$gamma$$-ray measurements by utilizing $$gamma$$-ray standard sources and neutron capture reactions are discussed. This work is supported by a MEXT program of "Fundamental research and development on neutron cross sections for innovative reactors using advanced radiation measurement technology".

Oral presentation

Neutron capture measurements using the 4$$pi$$ Ge detector for Au and Ag

Harada, Hideo; Kitatani, Fumito; Toh, Yosuke; Kimura, Atsushi; Nakamura, Shoji; Furutaka, Kazuyoshi; Koizumi, Mitsuo; Oshima, Masumi; Mizumoto, Motoharu*; Igashira, Masayuki*; et al.

no journal, , 

The $$gamma$$ rays produced by neutron capture reactions for Au and Ag samples were measured using the 4$$pi$$ Ge spectrometer in the resonance region in a time-of-flight (TOF) mode. Two dimensional matrices for TOF and summed Ge pulse heights were produced to analyze the data. From the analyses of the matrices, the origin of each resonance peak is identified. For example, the resonance of Ag-107 and Ag-109 were clearly separated in the measurement of Ag-nat sample by gating at the neutron separation energy for each isotope. Furthermore, the $$gamma$$-ray spectrum for each resonance is deduced from the matrices. The potential of the 4$$pi$$ Ge detector as the high-energy-resolution total energy absorption detector is demonstrated using the TOF data obtained for Au and Ag.

21 (Records 1-20 displayed on this page)