Papers - AKIMUNE Hidetoshi
-
GSO-detector system "NYMPHS" for (7Li, 7Be-γ) reaction at intermediate energies
S. Nakayama, K. Fushimi, H. Kohri, H. Akimune, I. Daito, H. Fujimura, Y. Fujita, M. Fujiwara, T. Inomata, K. Ishibashi, T. Iwawaki, N. Koori, K. Takahisa, A. Tamii, M. Tanaka, H. Toyokawa, T. Yamagata
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 404 ( 1 ) 34 - 40 1998.2
Joint Work
A γ-ray detector system "NYMPHS" was built for 7Be-γ coincidence measurements to separate (7Li, 7Beg.s.) and (7Li, 7Be0.43MeV) channels in the (7Li, 7Be) reaction at intermediate energies. NYMPHS is composed of 22 GSO scintillators, each with a volume of about 30 cm3. A typical energy resolution was about 9% at Eγ = 0.66 MeV.The absolute detection efficiency of NYMPHS was 0.200 ± 0.005 for the 0.43 MeV 7Be γ-ray. NYMPHS combined with a magnetic spectrograph showed good performance for 7Be-γ coincidence measurements in the (7Li, 7Be) reactions on 12C and 90Zr targets at EL = 65A MeV. © 1998 Elsevier Science B.V. All rights reserved.
-
Gamow-Teller strengths from (t,3He) charge-exchange reactions on light nuclei
I. Daito, H. Akimune, Sam M. Austin, D. Bazin, G. P.A. Berg, J. A. Brown, B. S. Davids, Y. Fujita, H. Fujimura, M. Fujiwara, R. Hazama, T. Inomata, K. Ishibashi, J. Jänecke, S. Nakayama, K. Pham, D. A. Roberts, B. M. Sherrill, M. Steiner, A. Tamii, M. Tanaka, H. Toyokawa, M. Yosoi
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 418 ( 1-2 ) 27 - 33 1998.1
Joint Work
Publisher：Elsevier
Zero-degree cross sections have been measured for (t,3He) reactions on the light target nuclei 9Be, 10B, 11B, 12C, and 13C at a bombarding energy of 127 MeV/A. The triton beam was produced by (4He,t + p) breakup on a Be production target using a 4He beam of 155 MeV/A. Dispersion matching was applied to obtain good energy resolution (ΔE/E = 0.002, ΔE = 780 keV). The zero-degree (t,3He) cross sections are used to discuss Gamow-Teller strengths in 10Be and 11Be. © 1998 Elsevier Science B.V.
-
The (7Li,7Be) reaction as a spin-probe for isovector excitations
S. Nakayama, H. Akimune, I. Daito, H. Fujimura, Y. Fujita, M. Fujiwara, K. Fushimi, T. Inomata, K. Ishibashi, H. Kohri, N. Koori, K. Takahisa, A. Tamii, M. Tanaka, H. Toyokawa, T. Yamagata
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 402 ( 2-3 ) 367 - 370 1998.1
Joint Work
The (7Li,7Be) reaction was found to be used to separate ΔS = 0 and ΔS = 1 transitions through the coincidence measurement of the γ-ray from deexcitation of the 0.43 MeV state of 7Be at an incident energy of 65 A MeV on 6Li, 7Li, 12C and 90Zr nuclei. The reaction was shown to proceed predominantly via one-step reaction process. Predominance of one-step process means utility for derivation of spin-flip and non spin-flip strengths for isovector excitations in medium heavy nuclei at intermediate incident energies. The relative nuclear spin-strength Psf was deduced for isovector excitations.
-
Erratum to "(t, He-3) reaction; New tool for studying spin-isospin excitations in neutron rich nuclei" (vol 397, pg 465, 1997) Reviewed
Daito I, Akimune H, Austin SM, Bazin D, Berg GPA, Brown JA, Davids BS, Fujita Y, Fujimura H, Fujimura M, Hazama R, Inomata T, Ishibashi K, Janecke J, Nakayama S, Pham K, Roberts DA, Sherrill BM, Steiner M, Tamii A, Tanaka M, Toyokawa H, Yosoi M
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 402 ( 1 ) 177 1998.1
-
Particle decays from [Formula Presented] and [Formula Presented] mirror nuclei Reviewed
T. Inomata, H. Akimune, I. Daito, H. Ejiri, H. Fujimura, Y. Fujita, M. Fujiwara, M. N. Harakeh, K. Ishibashi, H. Kohri, N. Matsuoka, S. Nakayama, A. Tamii, M. Tanaka, H. Toyokawa, M. Yoshimura, M. Yosoi
Physical Review C - Nuclear Physics 57 ( 6 ) 3153 - 3166 1998
Joint Work
Spin-isospin excitations in [Formula Presented] B and [Formula Presented] N have been studied using the [Formula Presented] C[Formula Presented],[Formula Presented] He)[Formula Presented] B and [Formula Presented] C[Formula Presented] He,[Formula Presented][Formula Presented] N charge-exchange reactions at [Formula Presented] = 0[Formula Presented] and at [Formula Presented]=200 MeV and [Formula Presented][Formula Presented] He)=450 MeV, respectively. Neutron decay from [Formula Presented] B to [Formula Presented] B and proton decay from [Formula Presented] N to [Formula Presented] C have been measured with detector arrays consisting of liquid-scintillation counters and silicon detectors, respectively. Microscopic structures of the spin-dipole resonances in [Formula Presented] B and [Formula Presented] N are discussed on the basis of the experimental observations of particle decays and their angular correlations. © 1998 The American Physical Society.
-
Low-lying states of [Formula Presented] Reviewed
R. De Leo, H. Akimune, N. Blasi, I. Daito, Y. Fujita, M. Fujiwara, S. I. Hayakawa, S. Hatori, H. Ikegami, T. Inomata, I. Katayama, K. Katori, L. Lagamba, S. Micheletti, S. Morinobu, R. Perrino, M. Pignanelli, H. Sakamoto, J. Takamatsu, M. Tosaki
Physical Review C - Nuclear Physics 57 ( 4 ) 1604 - 1616 1998
Joint Work
Low-lying states at [Formula Presented] of excitation energy in [Formula Presented] have been studied by means of inelastic deuteron scattering at [Formula Presented] The spin, parity, and isoscalar matrix element of detected levels have been deduced by comparing the measured cross sections with coupled-channel calculations using collective form factors. The present data for higher excitation energies have been analyzed by combining with previous data at lower excitation energies. The low-energy octupole strength in [Formula Presented] is found to be mostly located in the excitation energy range of [Formula Presented] The strength is weakly fragmented, and the [Formula Presented] level exhausts the major part of the octupole energy-weighted-sum-rule value. A similar behavior is observed for the quadrupole strength in [Formula Presented] which is mostly located below [Formula Presented] This is in contrast with the behavior of the [Formula Presented] and [Formula Presented] states in [Formula Presented] which are heavily fragmented despite the weaker quadrupole deformation. The hexadecapole strength is strongly fragmented both in [Formula Presented] and in [Formula Presented] The strength distributions for the transitions with multipolarities [Formula Presented] 3, and 4 in [Formula Presented] have been compared with random phase approximation calculations. The theoretical calculations show that the closure of the [Formula Presented] shell is responsible for the observed fragmentation of the [Formula Presented] and [Formula Presented] strengths in [Formula Presented] and that the collectivity of the [Formula Presented] and [Formula Presented] levels of [Formula Presented] is restored by the presence of two neutrons outside the [Formula Presented] shell. © 1998 The American Physical Society.
-
Elastic scattering of polarized protons from [Formula Presented] at [Formula Presented], 295, and 400 MeV Reviewed
H. Sakaguchi, H. Takeda, S. Toyama, M. Itoh, A. Yamagoshi, A. Tamii, M. Yosoi, H. Akimune, I. Daito, T. Inomata, T. Noro, Y. Hosono
Physical Review C - Nuclear Physics 57 ( 4 ) 1749 - 1755 1998
Joint Work
Elastic scattering of polarized protons from [Formula Presented] has been measured at incident proton energies of 192, 295, and 400 MeV. Optical model calculations employing relativistic impulse approximations and a microscopic folding model using a nonrelativistic [Formula Presented] matrix are compared with the experimental results. In order to explain the experiment further, it is necessary to use a density distribution deduced from the charge distribution measured by electron scattering and to modify the nucleon-nucleon interaction in the nuclear medium by altering coupling constants between nucleons and mesons and also adjusting the masses of exchanged mesons. © 1998 The American Physical Society.
-
Isospin and Spin-Orbital Structures of J($\pi$) = 1$^{+}$ States Excited in $^{28}$Si Reviewed
Y. Fujita, H. Akimune, I. Daito, M. Fujiwara, M. N. Harakeh, T. Inomata, J. Janecke, K. Katori, C. Luttge, S. Nakayama, P. von Neumann-Cosel, A. Richter, A. Tamii, M. Tanaka, H. Toyokawa, H. Ueno, M. Yosoi
Phys.Rev. C55 1137 1997.11
Joint Work
-
GT Strengths Studied by ($^{3}$He, t) Reactions and Nuclear Matrix Elements for Double Beta Decays Reviewed
H. Akimune, H. Ejiri, M. Fujiwara, I. Daito, T. Inomata, R. Hazama, A. Tamii, H. Toyokawa, M. Yosoi
Phys.Lett. 394B 23 1997.11
Joint Work
-
Evidence for the Isoscalar Giant Dipole Resonance in $^{208}$Pb using Inelastic $\alpha$ Scattering at and Near 0$^\circ$ Reviewed
B. F. Davis, U. Garg, W. Reviol, M. N. Harakeh, A. Bacher, G. P. A. Berg, C. C. Foster, E. J. Stephenson, Y. Wang, J. Janecke, K. Pham, D. Roberts, H. Akimune, M. Fujiwara, J. Lisantti
Phys.Rev.Lett. 79 609 1997.11
Joint Work
-
(t, $^{3}$He) Reaction; New tool for studying spin-isospin excitations in neutron rich nuclei Reviewed
I. Daito, H. Akimune, S. M. Austin, D. Bazin, G. P. A. Berg, J. A. Brown, B. S. Davids, Y. Fujita, H. Fujimura, M. Fujiwara, R. Hazama, T. Inomata, K. Ishibashi, J. Janecke, S. Nakayama, K. Pham, D. A. Roberts, B. M. Sherrill, M. Steiner, A. Tamii, M. Tanaka, H. Toyokawa, M. Yosoi
Nucl.Instrum.Methods Phys.Res. A397 465 1997.11
Joint Work
-
(t,3He) reaction; new tool for studying spin-isospin excitations in neutron rich nuclei
I. Daito, H. Akimune, S. M. Austin, D. Bazin, G. P.A. Berg, J. A. Brown, B. S. Davids, Y. Fujita, H. Fujimura, M. Fujiwara, R. Hazama, T. Inomata, K. Ishibashi, J. Jänecke, S. Nakayama, K. Pham, D. A. Roberts, B. M. Sherrill, M. Steiner, A. Tamii, M. Tanaka, H. Toyokawa, M. Yosoi
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 397 ( 2-3 ) 465 - 471 1997.10
Joint Work
Initial experiments were carried out to study spin-isospin transitions in nuclei using (t,3He) measurements. A triton beam was produced from the breakup reaction (4He,t-p) on a 9.25 g/cm2 Be production target using a 4He beam of 620 MeV. With a beam of 70 enA a yield of 381 MeV tritons with 4.5 × 106 particles/s was achieved. The first half of the A1200 beam transport system at NSCL was used to analyze the triton beam. The energy spread at the target position was estimated to be about 23 MeV. The second half of the A1200 was used to analyze the energy of 3He particles from the (t,3He) reaction. The dispersion matching method was applied to obtain good energy resolution despite the significant energy spread of the incident tritons. The achromatic properties of the A1200 system made it possible to obtain high-resolution (t,3He) spectra at θ = 0° with a resolution of ΔE/E = 0.002 (ΔE = 780 keV).
-
GT strengths studied by (3He, t) reactions and nuclear matrix elements for double beta decays
Hidetoshi Akimune, Hiroyasu Ejiri, Mamoru Fujiwara, Izuru Daito, Toru Inomata, Ryota Hazama, Atsushi Tamii, Hidenori Toyokawa, Mosaru Yosoi
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 394 ( 1-2 ) 23 - 28 1997.2
Joint Work
Publisher：Elsevier
GT matrix elements Mv S for transitions of 100Mo(0+) → 100Tc(1+) and 116Cd(0+) → 116In(1+) were obtained by measuring (3He, t) reactions on 100Mo and 116Cd, respectively. The values for Mv S, together with the GT matrix elements Mv S′ for 100Tc(1+) → 100Ru(0+) and 116In(1+) → 116Sn(0+), are applied to estimate the nuclear matrix elements M2v SS′, for the two neutrino double beta decays (2vββ) of 100Mo and 116Cd through the 1+ ground states in the intermediate nuclei of 100Tc and 116In, respectively. They are very close to the observed 2vββ matrix elements M2v, consistent with recent experimental and theoretical analyses.
-
Evidence for the isoscalar giant dipole resonance in 208 Pb using inelastic α scattering at and near 0°
B. F. Davis, U. Garg, W. Reviol, M. N. Harakeh, A. Bacher, G. P.A. Berg, C. C. Foster, E. J. Stephenson, Y. Wang, J. Jänecke, K. Pham, D. Roberts, H. Akimune, M. Fujiwara, J. Lisantti
Physical Review Letters 79 ( 4 ) 609 - 612 1997.1
Joint Work
The isoscalar giant dipole resonance (ISGDR) in 208 Pb has been investigated using inelastic scattering of 200 MeV α particles at and near 0° where the angular distribution of the ISGDR can be clearly differentiated from those of other modes. The “difference of spectra” technique was employed to separate the ISGDR from the high-energy octupole resonance (HEOR). These data provide the clearest evidence yet for the ISGDR adjacent to the HEOR. With these results, all expected isoscalar λ ≤ 3 resonances in 208Pb have been identified. © 1997 The American Physical Society.
-
Isospin and spin-orbital structures of [Formula Presented] states excited in [Formula Presented]Si Reviewed
Y. Fujita, H. Akimune, I. Daito, M. Fujiwara, M. N. Harakeh, T. Inomata, J. Jänecke, K. Katori, C. Lüttge, S. Nakayama, P. von Neumann-Cosel, A. Richter, A. Tamii, M. Tanaka, H. Toyokawa, H. Ueno, M. Yosoi
Physical Review C - Nuclear Physics 55 ( 3 ) 1137 - 1145 1997
Joint Work
Gamow-Teller (GT) states with [Formula Presented] = 1[Formula Presented] excited by a [Formula Presented]-type charge-exchange reaction on [Formula Presented] nuclei with ground-state isospin [Formula Presented] have isospin [Formula Presented], while [Formula Presented] states excited by inelastic scattering of electrons or protons can have either [Formula Presented] or [Formula Presented]. The latter are the isobaric analog states of the GT states. By comparing the GT states observed in the good-resolution [Formula Presented] reaction at 150 MeV/nucleon with the [Formula Presented] states observed in inelastic electron and proton reactions, the isospin structure of the [Formula Presented] states in [Formula Presented] has been determined. From an analysis of the strengths of corresponding [Formula Presented] states observed in the [Formula Presented] and [Formula Presented] reactions, the spin and orbital contributions to the [Formula Presented] excitations have been deduced. © 1997 The American Physical Society.
-
Isospin Decomposition of the Gamow-Teller Strength in $^{58}$Cu Reviewed
Y. Fujita, H. Akimune, I. Daito, M. Fujiwara, M. N. Harakeh, T. Inomata, J. Janecke, K. Katori, H. Nakada, S. Nakayama, A. Tamii, M. Tanaka, H. Toyokawa, M. Yosoi
Phys.Lett. 365B 29 1996.11
Joint Work
-
Spin Isospin Resonances in Nuclei Reviewed
M. Fujiwara, H. Akimune, I. Daito, H. Ejiri, Y. Fujita, M. B. Greenfield, M. N. Harakeh, T. Inomata, J. Janecke, S. Nakayama, N. Takemura, A. Tamii, M. Tanaka, H. Toyokawa, M. Yosoi
Nucl.Phys. A599 223c 1996.11
Joint Work
-
Isospin Character of Low-Lying States in $^{56}$Fe Reviewed
R. De Leo, H. Akimune, N. Blasi, I. Daito, Y. Fujita, M. Fujiwara, S. I. Hayakawa, S. Hatori, K. Hosono, H. Ikegami, T. Inomata, I. Katayama, K. Katori, L. Lagamba, S. Micheletti, S. Morinobu, T. Nakagawa, S. Nakayama, A. Narita, T. Noro, R. Perrino, M. Pignanelli, H. Sakaguchi, J. Takamatsu, A. Tamii, K. Tamura, M. Tanaka, A. Terakawa, T. Tohei, M. Tosaki, T. Yamagata, A. Yamagoshi, M. Yoshimura, M. Yosoi
Phys.Rev. C53 2718 1996.11
Joint Work
-
The ' Other ' Giant Dipole Resonance: Evidence for the isoscalar giant dipole resonance in $^{208}$Pb from inelastic $\alpha$ scattering at 0$^\circ$ Reviewed
B. F. Davis, H. Akimune, A. Bacher, G. P. A. Berg, C. C. Foster, M. Fujiwara, U. Garg, M. N. Harakeh, J. Janecke, J. Lisantti, K. Pham, W. Reviol, D. Roberts, E. J. Stephenson, Y. Wang
Nucl.Phys. A599 277c 1996.11
Joint Work
-
The "other" giant dipole resonance: Evidence for the isoscalar giant dipole resonance in 208Pb from inelastic α scattering at 0° Reviewed
B. F. Davis, H. Akimune, A. Bacher, G. P.A. Berg, C. C. Foster, M. Fujiwara, U. Garg, M. N. Harakeh, J. Jänecke, J. Lissanti, K. Pham, W. Reviol, D. Roberts, E. J. Stephenson, Y. Wang
Nuclear Physics A 599 ( 1-2 ) 277c 1996.3
Joint Work
Publisher：Elsevier
The isoscalar giant dipole resonance (ISGDR) in 208Pb has been investigated using inelastic scattering of 200 MeV α particles at and near 0° where the angular distribution of the ISGDR can be clearly differentiated from other modes. The "difference of spectra" technique was employed to separate the contribution from the high-energy octupole resonance (HEOR). Preliminary angular distribution data provide clear evidence for the ISGDR adjacent to the HEOR.