We have measured the 16O(p, d) reaction using 198-, 295- and 392-MeV proton beams to search for a direct evidence on an effect of the tensor interactions in light nucleus. Differential cross sections ...of the one-neutron transfer reaction populating the ground states and several low-lying excited states in 15O were measured. Comparing the ratios of the cross sections for each excited state to the one for the ground state over a wide range of momentum transfer, we found a marked enhancement of the ratio for the positive-parity state(s). The observation is consistent with large components of high-momentum neutrons in the initial ground-state configurations due to the tensor interactions.
The isoscalar giant dipole resonance (ISGDR) in 208Pb has been investigated with inelastic α-scattering of 400 MeV at extremely forward angles, including 0°. Energy spectra, virtually free from ...instrumental background, have been obtained and the ISGDR strength distribution has been extracted using a multipole-decomposition analysis (MDA). A difference-of-spectra approach yields the same ISGDR centroid energy as with MDA. These results lead to a value for nuclear incompressibility that is consistent for both the isoscalar dipole and monopole modes.
HD gas analysis with gas chromatography and quadrupole mass spectrometer Ohta, T.; Bouchigny, S.; Didelez, J.-P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2011, Letnik:
640, Številka:
1
Journal Article
Recenzirano
Odprti dostop
A gas analyzer system has been developed to analyze Hydrogen–Deuteride (HD) gas for producing frozen-spin polarized HD targets, which are used for hadron photoproduction experiments at SPring-8. ...Small amounts of ortho-H
2 and para-D
2 gas mixtures (
∼
0.01
%
) in a purified HD gas are a key to realize a frozen-spin polarized target. However, there was an intrinsic difficulty to measure these small mixtures in the HD gas with a quadrupole mass spectrometer (QMS) because D
+ and H
2D
+ produced from the ionization of HD molecules were misidentified as H
2 and D
2 molecules, respectively, and became backgrounds for the measurement of the H
2 and D
2 concentrations. In addition, the ortho-H
2 and para-D
2 are not distinguished from the para-H
2 and ortho-D
2, respectively, with the QMS. In order to obtain reliable concentrations of these gas mixtures in the HD gas, we produced a new gas analyzer system combining two independent measurements with a gas chromatograph and the QMS. Helium or neon gas was used as a carrier gas for the gas chromatograph which was cooled at
∼
110
K
. The para-H
2, ortho-H
2, HD, and D
2 are separated using the retention time of the gas chromatograph and the mass/charge ratio. Although the para-D
2 is not separated from the ortho-D
2, the total amount of the D
2 is measured without the H
2D
+ background. The ortho-H
2 concentration is also measured separately from the D
+ background. It is found that the new gas analyzer system can measure small concentrations of
∼
0.01
%
for the ortho-H
2 and D
2 with good
S
/
N
ratios.
Time-of-Propagation Counter for the LEPS Yoon, C. J.; Oka, M.; Ryu, S. Y. ...
IEEE transactions on nuclear science,
10/2014, Letnik:
61, Številka:
5
Journal Article
Recenzirano
We have tested a time-of-propagation (TOP) counter, which is a ring-image Cherenkov counter utilizing the position and propagation time of the Cherenkov light produced by particles moving in a quartz ...radiator. Position-sensitive photomultipliers (PMTs) are attached to the end of the quartz bar to detect the produced Cherenkov-ring image. The velocity of the charged particle was determined by comparing the time-of-propagation spectra of the Cherenkov light with the results of Monte Carlo simulation. From analysis of the test experiment using the 1.22-GeV/c electron beam at SPring-8, we determined the velocity of the electron beam to be 1.001 with a resolution of 0.002. On the basis of this study, we suggest a full setup for the detector for separating pions and kaons in the momentum region from 1.5 to 2.0 GeV/c for a beam angle of less than 6°, by more than four standard deviations.
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