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Journal Articles

Accurate estimation of spectral density of LCS gamma-ray source

Omer, M.; Shizuma, Toshiyuki*; Hajima, Ryoichi*; Koizumi, Mitsuo

Dai-43-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 3 Pages, 2022/11

Journal Articles

Low-lying dipole strength distribution in $$^{204}$$Pb

Shizuma, Toshiyuki*; Endo, Shunsuke; Kimura, Atsushi; Massarczyk, R.*; Schwengner, R.*; Beyer, R.*; Hensel, T.*; Hoffmann, H.*; Junghans, A.*; R$"o$mer, K.*; et al.

Physical Review C, 106(4), p.044326_1 - 044326_11, 2022/10

 Times Cited Count:0 Percentile:0.02(Physics, Nuclear)

no abstracts in English

Journal Articles

Calculating off-axis efficiency of coaxial HPGe detectors by Monte Carlo simulation

Omer, M.; Shizuma, Toshiyuki*; Hajima, Ryoichi*; Koizumi, Mitsuo

Radiation Physics and Chemistry, 198, p.110241_1 - 110241_7, 2022/09

 Times Cited Count:1 Percentile:71.47(Chemistry, Physical)

Journal Articles

Evaluation of analyzing power of gamma-ray polarimeter

Endo, Shunsuke; Shizuma, Toshiyuki*; Zen, H.*; Taira, Yoshitaka*; Omer, M.; Kawamura, Shiori*; Abe, Ryota*; Okudaira, Takuya*; Kitaguchi, Masaaki*; Shimizu, Hirohiko*

UVSOR-49, P. 38, 2022/08

Journal Articles

Isomer production ratio of the $$^{112}$$Cd($$n,gamma$$)$$^{113}$$Cd reaction in an $$s$$-process branching point

Hayakawa, Takehito*; Toh, Yosuke; Kimura, Atsushi; Nakamura, Shoji; Shizuma, Toshiyuki*; Iwamoto, Nobuyuki; Chiba, Satoshi*; Kajino, Toshitaka*

Physical Review C, 103(4), p.045801_1 - 045801_5, 2021/04

 Times Cited Count:0 Percentile:0.02(Physics, Nuclear)

Journal Articles

High-spin states in $$^{35}$$S

Go, Shintaro*; Ideguchi, Eiji*; Yokoyama, Rin*; Aoi, Nori*; Azaiez, F.*; Furutaka, Kazuyoshi; Hatsukawa, Yuichi; Kimura, Atsushi; Kisamori, Keiichi*; Kobayashi, Motoki*; et al.

Physical Review C, 103(3), p.034327_1 - 034327_8, 2021/03

 Times Cited Count:3 Percentile:67.04(Physics, Nuclear)

Journal Articles

Low-lying electric and magnetic dipole strengths in $$^{207}$$Pb

Shizuma, Toshiyuki*; Minato, Futoshi; Omer, M.*; Hayakawa, Takehito*; Ogaki, Hideaki*; Miyamoto, Shuji*

Physical Review C, 103(2), p.024309_1 - 024309_8, 2021/02


 Times Cited Count:3 Percentile:67.04(Physics, Nuclear)

Low-lying dipole transitions in $$^{207}$$Pb were measured via nuclear photon scattering using a quasi-monochromatic, linearly polarized photon beam. The electric ($$E1$$) and magnetic ($$M1$$) dipole strengths were extracted for excitation energies up to 6.8 MeV. The present ($$vec{gamma}$$,$$gamma'$$) results, combined with ($$gamma$$,$$n$$) data from the literature, were used to investigate the $$E1$$ and $$M1$$ photoabsorption cross sections near the neutron separation energy by comparison with predictions of the particle-vibration coupling on top of the quasi-particle random phase approximation (PVC+QRPA).

Journal Articles

Compton scattering of quasi-monochromatic $$gamma$$-ray beam

Omer, M.; Shizuma, Toshiyuki*; Hajima, Ryoichi*

Nuclear Instruments and Methods in Physics Research A, 951, p.162998_1 - 162998_6, 2020/01

 Times Cited Count:1 Percentile:18.5(Instruments & Instrumentation)

Journal Articles

Testing enrichment meter based on nuclear resonance fluorescence

Omer, M.; Shizuma, Toshiyuki*; Hajima, Ryoichi*; Koizumi, Mitsuo

Nihon Kaku Busshitsu Kanri Gakkai Dai-40-Kai Nenji Taikai Puroshidhingusushu, p.59 - 62, 2019/11

Journal Articles

Spin and parity determination of the 3.004-MeV level in $$^{27}$$Al; Its low-lying multiplet structure

Shizuma, Toshiyuki*; Omer, M.; Hajima, Ryoichi*; Shimizu, Noritaka*; Utsuno, Yutaka

Physical Review C, 100(1), p.014307_1 - 014307_6, 2019/07

 Times Cited Count:6 Percentile:62.36(Physics, Nuclear)

Journal Articles

Dipole strength distribution in $$^{206}$$Pb for the evaluation of the neutron capture cross section of $$^{205}$$Pb

Shizuma, Toshiyuki; Iwamoto, Nobuyuki; Makinaga, Ayano*; Massarczyk, R.*; Schwengner, R.*; Beyer, R.*; Bemmerer, D.*; Dietz, M.*; Junghans, A.*; K$"o$gler, T.*; et al.

Physical Review C, 98(6), p.064317_1 - 064317_12, 2018/12

 Times Cited Count:9 Percentile:67.39(Physics, Nuclear)

The dipole strength distribution of $$^{206}$$Pb was investigated via a nuclear resonance fluorescence experiment using bremsstrahlung produced with an electron beam at a kinetic energy of 10.5 MeV at the linear accelerator ELBE. We identified 88 states resonantly excited at energies from 3.7 to 8.2 MeV. The photo-absorption cross sections were extracted from the measured scattering cross sections and the branching ratios. The present ($$gamma$$,$$gamma'$$) data combined with ($$gamma$$,$$n$$) data from the literature were used as an input to the statistical calculation code CCONE to evaluate the neutron capture cross section of the unstable $$^{205}$$Pb nucleus.

Journal Articles

Evaluation of neutron capture cross section on $$^{205}$$Pb with photonuclear data

Iwamoto, Nobuyuki; Shizuma, Toshiyuki*

EPJ Web of Conferences, 178, p.06004_1 - 06004_3, 2018/05

 Times Cited Count:0 Percentile:0

Journal Articles

Low-lying dipole strength in $$^{52}$$Cr

Shizuma, Toshiyuki*; Hayakawa, Takehito*; Daito, Izuru*; Ogaki, Hideaki*; Miyamoto, Shuji*; Minato, Futoshi

Physical Review C, 96(4), p.044316_1 - 044316_10, 2017/10

 Times Cited Count:8 Percentile:60.25(Physics, Nuclear)

The low-lying dipole strength in $$^{52}$$Cr was measured in nuclear resonance fluorescence experiments using a quasi-monochromatic, linearly polarized photon beam. The parities of the excited dipole states were determined by the intensity asymmetry of resonantly scattered $$gamma$$-rays with respect to the polarization plane of the incident photon beam. The summed magnetic dipole (M1) strength was determined as $$sum B(M1)uparrow=5.64(34) mu_N^2$$ at excitation energies between 7.5 and 12.1 MeV; the summed electric dipole (E1) strength was obtained as $$sum B(E1)uparrow=73.7(23) times 10^{-3} e^2$$ fm$$^2$$. The observed M1 and E1 strengths were compared via random phase approximation calculations using the Skyrme interaction. The effects of 2 particle-2 hole configuration mixing and tensor force on dipole strength distributions were investigated.

Journal Articles

Effects of $$gamma$$-ray polarization in NRF-based nondestructive assay of nuclear materials

Omer, M.; Hajima, Ryoichi*; Shizuma, Toshiyuki*; Koizumi, Mitsuo

Proceedings of INMM 58th Annual Meeting (Internet), 7 Pages, 2017/07

Nuclear resonance fluorescence (NRF) is a process in which the electric and/or the magnetic dipole excitations of the nucleus take place. Since these excitations are unique signatures of each nucleus, the NRF provides a practical tool for a non-destructive detection and assay of nuclear materials. Using a polarized $$gamma$$-ray beam, distinguishing the nature of the excitation is straightforward. At a scattering angle of 90$$^{circ}$$, the electric dipole excitations are radiated normal to the polarization plane whereas the magnetic dipole excitations are radiated in the same plane as the incident beam polarization. By contrast, other $$gamma$$-ray interactions with the atom may exhibit different responses regarding the polarization of the incident beam. For example, the elastic scattering is expected to give approximately 60% lower yield in the direction of the incident beam polarization than the other direction. This fact significantly affects the sensitivity of the NRF technique because it is not possible to separate the NRF and the elastic scattering on the basis of the photon energy. We report the results of a photon scattering experiment on $$^{238}$$U using a 100% linearly polarized $$gamma$$-ray beam with an energy of 2.04 MeV. We demonstrate how the elastic scattering responds to the polarization of the incident beam. Accordingly, we are able to resolve the effects of the polarization of incident photon in an NRF measurement.

Journal Articles

Measurement of the isomer production ratio for the $$^{112}$$Cd($$n,gamma$$)$$^{113}$$Cd reaction using neutron beams at J-PARC

Hayakawa, Takehito*; Toh, Yosuke; Huang, M.; Shizuma, Toshiyuki*; Kimura, Atsushi; Nakamura, Shoji; Harada, Hideo; Iwamoto, Nobuyuki; Chiba, Satoshi*; Kajino, Toshitaka*

Physical Review C, 94(5), p.055803_1 - 055803_6, 2016/11

 Times Cited Count:4 Percentile:36.17(Physics, Nuclear)

Journal Articles

Simulation of the elastic scattering contributions to the NRF-based nondestructive assay of nuclear materials

Omer, M.; Hajima, Ryoichi*; Angell, C.*; Shizuma, Toshiyuki*; Hayakawa, Takehito*; Seya, Michio; Koizumi, Mitsuo

Proceedings of INMM 57th Annual Meeting (Internet), 9 Pages, 2016/07

Isotope-specific $$gamma$$-rays emitted in the nuclear resonance fluorescence (NRF) process provide a good technique for a non-destructive detection and assay of nuclear materials. We are developing technologies relevant to $$gamma$$-ray nondestructive detection and assay utilizing NRF. A Monte Carlo code to simulate NRF process is necessary for design and evaluation of NDA systems. We are developing NRFGeant4, a Geant4-based simulation code, for this purpose. In NRF experiments, highly-enriched targets are generally used such that the NRF signals are dominant and easily measured. In contrast, a real situation may involve very small contents of isotopes of interest. This results in a difficulty in measuring NRF signals because of the interference with other interactions, e.g. elastic scattering. For example, a typical nuclear fuel pellet contains about 90% of $$^{238}$$U as a host material and less than 1% of $$^{239}$$Pu as an isotope of interest. When measuring NRF of $$^{239}$$Pu, there would be a huge background coming from the elastic scattering of $$^{238}$$U. Therefore, an estimation of the elastic scattering with the host material is essential for precise determination of isotope of interest. Satisfying estimation of elastic scattering is currently not available except for some calculations. In the present study, we upgrade our simulation code to include the calculation of elastic scattering events.

Journal Articles

Generation and applications of laser Compton scattered $$gamma$$-ray beams

Hajima, Ryoichi; Sawamura, Masaru; Nagai, Ryoji; Nishimori, Nobuyuki; Hayakawa, Takehito; Shizuma, Toshiyuki; Angell, C.

Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.79 - 83, 2015/09

Generation of energy-tunable narrow-bandwidth $$gamma$$-rays via Laser Compton Scattering (LCS) is of great interest for scientific studies and applications of MeV photons which interact with nuclei. We are developing technologies relevant to generation of high-brightness LCS $$gamma$$-ray beams. One of the promising applications of such $$gamma$$-rays is the nondestructive detection and assay of nuclides which are necessary for nuclear security and safeguards. We summarize R-and-D status of LCS $$gamma$$-ray sources and overview future applications.

Journal Articles

Demonstration of laser Compton-scattered photon source at the cERL

Nagai, Ryoji; Hajima, Ryoichi; Shizuma, Toshiyuki; Mori, Michiaki; Akagi, Tomoya*; Kosuge, Atsushi*; Honda, Yosuke*; Araki, Sakae*; Terunuma, Nobuhiro*; Urakawa, Junji*

Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1328 - 1330, 2015/09

Accelerator and laser technologies required for laser Compton scattering (LCS) photon source based on an energy-recovery linac (ERL) have been developed at the Compact ERL (cERL) facility. A high-flux, energy tunable, and monochromatic photon source such as the ERL-based LCS photon source is necessary for nondestructive assay of nuclear materials. For the demonstration of the ERL-based LCS photon generation, a laser enhancement cavity was installed at the recirculation loop of the cERL. The electron beam energy, the laser wavelength, and the collision angle are 20 MeV, 1064 nm, and 18 $$^{circ}$$, respectively. The calculated maximum energy of the LCS photons is about 7 keV. A silicon drift detector (SDD) with active area of 17 mm$$^{2}$$ placed 16.6 m from the collision point was used for observation of the LCS photons. As a result of the measurement, the flux on the detector, central energy, and energy width of the LCS photons were obtained as 1200/s, 6.91 keV, and 81 eV, respectively.

Journal Articles

R&D status of nondestructive assay system based on nuclear resonance fluorescence

Shizuma, Toshiyuki; Hajima, Ryoichi; Hayakawa, Takehito; Angell, C.; Seya, Michio

Proceedings of 37th ESARDA Annual Meeting (Internet), p.838 - 845, 2015/08

Nondestructive assay (NDA) of nuclear materials is an important technology for nuclear security and safeguard applications. We have proposed an NDA system based on nuclear resonance fluorescence (NRF). In the proposed detection system, an energy-tunable and mono-energetic $$gamma$$-ray source generated by Compton scattering of laser light (laser Compton scattering; LCS) with high-energy electrons is used. The NRF measurement can be more efficient by using a mono-energetic $$gamma$$-ray beam, which has been demonstrated in recent NRF measurements. We have started a research and development program of the LCS $$gamma$$-ray NDA systems, which includes demonstration of LCS $$gamma$$-ray generation from an energy recovery linac (ERL), establishment of detection system, and benchmark of Monte Carlo simulation. The R&D status including recent results on the demonstrations of the LCS photon generation as well as the measurement principles will be reported.

Journal Articles

Demonstrating the integral resonance transmission method; Conceptual and experimental studies

Angell, C.; Hayakawa, Takehito; Shizuma, Toshiyuki; Hajima, Ryoichi; Quiter, B. J.*; Ludewigt, B. L.*; Karwowski, H. J.*; Rich, G.*; Silano, J.*

Proceedings of INMM 56th Annual Meeting (Internet), 9 Pages, 2015/07

301 (Records 1-20 displayed on this page)