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Journal Articles

Dipole strength distributions in $$^{56}$$Fe

Shizuma, Toshiyuki; Hayakawa, Takehito; Ogaki, Hideaki; Toyokawa, Hiroyuki*; Komatsubara, Tetsuro*; Kikuzawa, Nobuhiro; Inakura, Tsunenori*; Homma, Michio*; Nakada, Hitoshi*

Physical Review C, 87(2), p.024301_1 - 024301_7, 2013/02

 Times Cited Count:13 Percentile:28.51(Physics, Nuclear)

Electro-magnetic dipole transitions in $$^{56}$$Fe were measured in photon scattering experiments with a linearly polarized photon beam. The parity quantum numbers 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. While the summed magnetic dipole ($$M1$$) strength was determined as $$Sigma B(M1)!uparrow=3.52(17)$$ $$mu_N^2$$ at excitation energies between 7 and 10 MeV, the summed electric dipole ($$E1$$) strength below 10 MeV was obtained as $$Sigma B(E1)!uparrow=78.0(15)times10^{-3},e^2{rm fm}^2$$. The observed $$M1$$ strength was compared with shell-model predictions in the $$pf$$-shell using the GXPF1J and KB3G effective interactions. In addition, the $$E1$$ strength was compared with random-phase approximation calculations with the Skyrme interaction.

Journal Articles

Spins and parities of astrophysically important $$^{30}$$S states from $$^{28}$$Si($$^{3}$$He, $$n$$$$gamma$$)$$^{30}$$S

Setoodehnia, K.*; Chen, A. A.*; Komatsubara, Tetsuro*; Kubono, Shigeru*; Binh, D. N.*; Carpino, J. F.*; Chen, J.*; Hashimoto, Takashi*; Hayakawa, Takehito; Ishibashi, Yoko*; et al.

Physical Review C, 83(1), p.018803_1 - 018803_4, 2011/01

 Times Cited Count:12 Percentile:33.36(Physics, Nuclear)

The structure of proton-unbound $$^{30}$$S states strongly determines the thermonuclear $$^{29}$$P($$p$$, $$gamma$$)$$^{30}$$S reaction rate at temperatures characteristic of explosive hydrogen burning in classical novae and type I X-ray bursts. Specifically, the rate had been previously predicted to be dominated by two low-lying, unobserved, levels in the $$E$$$$_{x}$$=4.7-4.8 MeV region, with spin and parity assignments of 3$$^{+}$$ and 2$$^{+}$$. In recent experimental work, two candidate levels were observed with energies of 4.699 MeV and 4.814 MeV, but no experimental information on their spins and parities was obtained. We have performed an in-beam $$gamma$$-ray spectroscopy study of $$^{30}$$S with the $$^{28}$$Si($$^{3}$$He, $$n$$$$gamma$$)$$^{30}$$S reaction. The spin and parities were inferred from a comparison to the known decay schemes of the corresponding mirror states.

Journal Articles

Fine structure of the magnetic-dipole-strength distribution in $$^{208}$$Pb

Shizuma, Toshiyuki; Hayakawa, Takehito; Ogaki, Hideaki*; Toyokawa, Hiroyuki*; Komatsubara, Tetsuro*; Kikuzawa, Nobuhiro; Tamii, Atsushi*; Nakada, Hitoshi*

Physical Review C, 78(6), p.061303_1 - 061303_4, 2008/12

 Times Cited Count:69 Percentile:4.18(Physics, Nuclear)

Spin-flip $$M1$$ strength in $$^{208}$$Pb has been measured in photon scattering experiments with a quasi-monochromatic, linearly polarized photon beam. The data resolve an $$M1$$ giant resonance into at least seven, possibly eight, discrete transitions at excitation energies between 7.1 and 7.4 MeV below the neutron separation energy. The measured $$M1$$ strength in this region is found to be larger than the previous report. The experimental results are compared with an estimation of self-consistent random phase approximation using a semi-realistic interaction.

Journal Articles

Gated multiple-sampling and tracking proportional chamber; New detector system for nuclear astrophysical study with radioactive nuclear beams

Hashimoto, Takashi; Ishiyama, Hironobu*; Ishikawa, Tomoko*; Kawamura, Takashi*; Nakai, Koji*; Watanabe, Yutaka*; Miyatake, Hiroari; Tanaka, Masahiko*; Fuchi, Yoshihide*; Yoshikawa, Nobuharu*; et al.

Nuclear Instruments and Methods in Physics Research A, 556(1), p.339 - 349, 2006/01

 Times Cited Count:29 Percentile:10.16(Instruments & Instrumentation)

A new type of three dimensional tracking and proportional gas counter has been developed. Adopting a gating-grid system, performance of the detector becomes stable under the injection rate of charged particles less than 4$$times$$10$$^4$$ pps. It is a useful detection system for astrophysical experiments using radioactive nuclear beams, since the efficiency is so high as 100 %.

Journal Articles

Multi-quasiparticle excitations in $$^{145}$$Tb

Zheng, Y.*; Zhou, X. H.*; Zhang, Y. H.*; Hayakawa, Takehito; Oshima, Masumi; Toh, Yosuke; Shizuma, Toshiyuki; Katakura, Junichi; Hatsukawa, Yuichi; Matsuda, Makoto; et al.

Journal of Physics G; Nuclear and Particle Physics, 30(4), p.465 - 479, 2004/04

 Times Cited Count:8 Percentile:49.51(Physics, Nuclear)

no abstracts in English

Journal Articles

High-$$K$$ negative parity states in $$^{184}$$Os

Shizuma, Toshiyuki; Stevenson, P. D.*; Walker, P. M.*; Toh, Yosuke; Hayakawa, Takehito; Oshima, Masumi; Furuno, Kohei*; Komatsubara, Tetsuro*

Physical Review C, 65(6), p.064310_1 - 064310_12, 2002/06

 Times Cited Count:13 Percentile:39.02(Physics, Nuclear)

High-spin states in $$^{184}$$Os have been studied using the $$^{170}$$Er($$^{18}$$O,4n) reaction at a beam energy of 85 MeV. Several new negative parity levels including a 48-ns $$K^pi=(18^-)$$ isomer have been identified. Nilsson configurations for the levels are assigned by comparison with multi-quasiparticle calculations. Potential-energy-surface calculations show an increasing influence of triaxiality in nuclear shapes at higher spins. The decay rate of the $$K^pi=(18^-)$$ isomer is discussed in relation to the role of the $$K$$ quantum number.

Journal Articles

Configuration-dependent band structures in odd-odd $$^{180}$$Ir

Zhang, Y.*; Hayakawa, Takehito; Oshima, Masumi; Katakura, Junichi; Hatsukawa, Yuichi; Matsuda, Makoto; Kusakari, Hideshige*; Sugawara, Masahiko*; Komatsubara, Tetsuro*; Furuno, Kohei*

Physical Review C, 65(1), p.014302_1 - 014302_15, 2002/01

 Times Cited Count:20 Percentile:27.45(Physics, Nuclear)

no abstracts in English

Journal Articles

Multi-quasiparticle states and ${it K}$-forbidden transitions in $$^{183}$$Os

Shizuma, Toshiyuki; Matsuura, Katsuyuki*; Toh, Yosuke; Hayakawa, Takehito; Oshima, Masumi; Hatsukawa, Yuichi; Matsuda, Makoto; Furuno, Kohei*; Sasaki, Yasuyuki*; Komatsubara, Tetsuro*; et al.

Nuclear Physics A, 696(3-4), p.337 - 370, 2001/12

 Times Cited Count:18 Percentile:26.93

High-spin states in $$^{183}$$Os have been studied using the 170Er(18O,5n) reaction at a beam energy of 85 MeV. Nine rotational bands based on 1-, 3-, 5- and 7-quasiparticle excitations have been observed. Nilsson configurations are assigned for the newly observed bands using g-factors deduced from M1/E2 branching ratios within the bands. In addition, two isomers with K=(43/2+) and (43/2-) have been identified. The K=(43/2+) isomer decays directly to the K=9/2+ ground state band with a large difference in the $$K$$ quantum number, $$mitDelta K=$$17. The decay rates are disccused in terms of a tunneling model where high-$$K$$ (isomeric) and low-$$K$$ states interact via fluctuations towards triaxial nuclear shapes.

Journal Articles

Observation of signature inversion in odd-odd $$^{178}$$Ir

Zhang, Y. H.*; Hayakawa, Takehito; Oshima, Masumi; Toh, Yosuke; Katakura, Junichi; Hatsukawa, Yuichi; Matsuda, Makoto; Shinohara, Nobuo; Ishii, Tetsuro; Kusakari, Hideshige*; et al.

European Physical Journal A, 8(4), p.439 - 442, 2000/09

 Times Cited Count:14 Percentile:37.07(Physics, Nuclear)

no abstracts in English

Journal Articles

Rotational bands in odd-odd $$^{180}$$Ir

Zhang, Y.*; Hayakawa, Takehito; Oshima, Masumi; Katakura, Junichi; Hatsukawa, Yuichi; Matsuda, Makoto; Kusakari, Hideshige*; Sugawara, Masahiko*; Komatsubara, Tetsuro*

AIP Conference Proceedings 495, p.247 - 248, 1999/12

no abstracts in English

Journal Articles

Rotational bands in odd-odd $$^{180}$$Ir

Zhang, Y.*; Hayakawa, Takehito; Oshima, Masumi; Katakura, Junichi; Hatsukawa, Yuichi; Matsuda, Makoto; Kusakari, Hideshige*; Sugawara, Masahiko*; Komatsubara, Tetsuro*

European Physical Journal A, 5(4), p.345 - 349, 1999/00

no abstracts in English

Journal Articles

A $$gamma$$-ray detector array for joint spectroscopy experiments at the JAERI tandem-booster facility

Oshima, Masumi; Furuno, Kohei*; Komatsubara, Tetsuro*; *; Hayakawa, Takehito*; *; ; ; *; *; et al.

Nuclear Instruments and Methods in Physics Research A, 421(1-2), p.211 - 226, 1999/00

 Times Cited Count:94 Percentile:1.19

no abstracts in English

Journal Articles

Measurement of the lifetime of the first 2$$^{+}$$ state in $$^{124}$$Ba

*; Furuno, Kohei*; *; ; *; *; *; *; *; Komatsubara, Tetsuro*; et al.

European Physical Journal A, 2(1), p.13 - 15, 1998/00

 Times Cited Count:9 Percentile:48.24(Physics, Nuclear)

no abstracts in English

Journal Articles

High spin states of $$^{132}$$Cs

Hayakawa, Takehito*; J.Lu*; Furuno, Kohei*; *; *; *; Komatsubara, Tetsuro*; Oshima, Masumi; ; *; et al.

Z. Phys., A, 357(4), p.349 - 350, 1997/00

no abstracts in English

Journal Articles

High spin states of $$^{62,64}$$Zn

*; Hayakawa, Takehito*; *; ; *; Oshima, Masumi; *; Komatsubara, Tetsuro*; ; Furuno, Kohei*; et al.

Z. Phys., A, 358, p.279 - 280, 1997/00

no abstracts in English

Journal Articles

High-spin states $$^{61}$$Cu

; Hayakawa, Takehito*; *; *; *; Ishii, Tetsuro; Oshima, Masumi; *; Kusakari, Hideshige*; Sugawara, Masahiko*; et al.

Z. Phys., A, 359, p.3 - 4, 1997/00

no abstracts in English

Journal Articles

High-spin states in nuclei at A=60 region

Oshima, Masumi; Furuno, Kohei*; Komatsubara, Tetsuro*; Hayakawa, Takehito*; *; *; *; *; ; Ishii, Tetsuro

Chujukaku No Kozo (Riken Shimpojiumu), 0, p.72 - 77, 1996/00

no abstracts in English

Oral presentation

Measurements of E1, M1 and E2 transition strength in $$^{208}$$Pb using laser Compton scattering $$gamma$$ rays

Shizuma, Toshiyuki; Hayakawa, Takehito; Ogaki, Hideaki*; Toyokawa, Hiroyuki*; Komatsubara, Tetsuro*; Kikuzawa, Nobuhiro; Tamii, Atsushi*; Nakada, Hitoshi*

no journal, , 

no abstracts in English

Oral presentation

Photon scattering experiments on nuclei at iron region using a $$gamma$$-ray beam from inverse Compton scattering

Shizuma, Toshiyuki; Hayakawa, Takehito; Kikuzawa, Nobuhiro; Ogaki, Hideaki*; Toyokawa, Hiroyuki*; Komatsubara, Tetsuro*

no journal, , 

no abstracts in English

Oral presentation

Nuclear photon scattering experiments by quasi-monochromatic, linearly polarized light sources

Shizuma, Toshiyuki; Hayakawa, Takehito; Ogaki, Hideaki; Toyokawa, Hiroyuki*; Komatsubara, Tetsuro*; Kikuzawa, Nobuhiro; Tamii, Atsushi*; Nakada, Hitoshi*

no journal, , 

The knowledge of the M1 response allows one to elucidate the details of nuclear dynamics. It is also important for the estimate neutral current neutrino-nucleus cross sections for supernova explosion. Low-lying electromagnetic transitions can be studied by the method of nuclear resonance fluorescence (NRF). Recently, it has been shown that quasi-monochromatic, linearly polarized photon beams from inverse laser Compton scattering has considerably increased experimental sensitivity and to enable one to detect the fine structure of relatively weak M1 transitions. In this report, results of the NRF measurements on $$^{208}$$Pb using a linearly polarized photon beam will be presented. The M1 resonance below the neutron separation energy is resolved into several individual transitions. The experimental results are compared with an estimation of self-consistent random phase approximation using a semi-realistic interaction.

24 (Records 1-20 displayed on this page)