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A fusion reaction of 12C+4He→16O+γ is one of the main reactions in He-burning of stars and important for nucleosynthesis. The fusion cross section at stellar energy of Ecm = 0.3 MeV has not been determined precisely yet in spite of efforts for about 40 years. We plan to measure directly the total fusion cross section down to 0.7 MeV at Kyushu University Tandem accelerator Laboratory and to estimate the cross section at 0.3MeV by extrapolation. We have already measured the cross sections at 2.4 MeV and 1.5 MeV. The measurement at Ecm=1.2 MeV is in progress. [ABSTRACT FROM AUTHOR]

A cross section measurement with a direct 16O detection method for the reaction energy from Ecm = 2.4 down to 0.7 MeV is planned at Kyushu University Tandem Laboratory (KUTL). To perform the experiment successfully and to get the quantitative information of the cross section within the 10% error, we have newly developed several instruments in 2009, such as a blow-in type windowless gas target and movable slit system placed in the recoil mass separator. By using the windowless blow-in gas target, a pressure of 24 Torr was achieved. The effective thickness along the beam axis was measured by p+4He scattering. Thanks to the movable slits installed in a recoil mass separator and the trajectory analysis, we found effective reduction of background conditions from the 12C beam. [ABSTRACT FROM AUTHOR]

We studied transition strengths to isovector dipole resonances (GDR-1[overbar], SDR-1[overbar], and SDR-2[overbar]) in 4He by using the 4He(7Li,7Beγ) reaction at 455 MeV and by comparing with shell-model calculations, in order to estimate cross sections of 4He for reactions induced by neutrinos emitting from a thermalized neutrino-sphere in the type-II supernova. Excitation of the SDR was dominant in the neutrino-heating of 4He. The 4He-excitation via neutral-current reactions of νμ,τ and νμ,τ was found to be one order of magnitude stronger than that via charged-current reactions of νe and νe. The total energy-weighted cross section <ωσ>N for neutrino-induced neutral-current reactions on 4He was found to amount to about 1.0×10-40 MeV·cm2 which is comparable to those used in the previous simulations. The neutrino-heating effect of 4He is small in the type-II supernova explosion. [ABSTRACT FROM AUTHOR]

Recently it was found that the differential cross sections of elastic Nd scattering below 150 MeV can be well reproduced by incorporating a 3NF in Faddeev calculations based on modern nucleon-nucleon (NN) interactions. On the other hand, the differential cross sections for nd and pd at 250 MeV show large discrepancies between the data and the Faddeev calculations with a 3NF. This indicates the existence of the missing features of the three nucleon force in this energy region. For the next step in the 3NF study, we have measured the vector analyzing power Ay and the differential cross sections for the 2H(pvector ,pp)n breakup reaction at 250 MeV. The experiment was carried out by detecting two protons in the final state with using the double-armed spectrometer Grand Raiden (GR) and the Large Acceptance Spectrometer (LAS) at the Research Center for Nuclear Physics (RCNP). The data was compared with the results of Faddeev calculations with and without a 3NF. [ABSTRACT FROM AUTHOR]

The isovector giant dipole resonance (GDR) of the α-clusters in 6Li and 7Li, and the GDR in 4He were investigated by using the 6,7Li(p,p′) and 4He(p,p′) reactions, respectively, at an incident energy of 300 MeV. The cross sections for the excitation of the GDR in the α clusters in 6,7Li normalized with the spectroscopic factors of the α-particle for 6,7Li agreed to the GDR cross section in 4He. The excitation energies and widths for the GDR in α clusters were larger than those for the GDR in 4He by 2–4 MeV and 0.5–4 MeV, respectively. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The results of experimental studies of three-nucleon systems will be presented, i.e. the pvector d elastic scattering at Ep = 250 MeV and the dvector p → 3He+γ capture reaction at Ed = 200 MeV. The angular distributions of the cross section and all the proton spin observables were measured for elastic scattering, and the cross section and analyzing powers, Ay, Axx and Ayy for the capture reaction. The results are compared with theoretical predictions based on exact solutions of the three-nucleon Faddeev equations and modern realistic nucleon-nucleon potentials combined with three-nucleon forces. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Analyzing power A[sub y](θ) of nd scattering was accurately measured at E[sub n] =12 and 16 MeV. Polarization of the n-beam produced by spin transfer ²H(d, n)³He reaction at 0° was determined in a separate experiment using [sup 4]He(n, n) scattering. The present nd A[sub y](θ) data are consistent with the existing nd A[sub y](θ) data below E[sub n] = 14.1 MeV. It was confirmed that the difference between nd A[sub y] and pd A[sub y] becomes large above 14 MeV and the assumption on slow-down effects by Coulomb force breaks down. The observed large difference in A[sub y](θ) requires systematic calculations with exact treatment of Coulomb force to study charge symmetry in nuclear force. [ABSTRACT FROM AUTHOR]

A 12C+4He→16O+γ is regarded as the very important reaction to know the evolution of heavy stars. The cross section is, however, still unknown in spite of more than 40 years experiment in the world because of an existence of a resonance state of 16O at sub-threshold region. A cross section measurement with the direct detection of the produced 16O from Ecm = 2.4 downto 0.7 MeV have been planned at Kyushu University Tandem Laboratory(KUTL). Detection of the 16O is the most possible method at low energy, since a detection efficiency of the 16O is very high. The new windowless blow-in gas target was developed to achieve the pressure of 24 Torr. Many movable slit were installed in a recoil mass separator, so that the backgrounds generated by the 12C beam was eliminated effectively. The results of recent experiments at Ecm = 2.4 and 1.5 MeV are reported. [ABSTRACT FROM AUTHOR]

The C-alpha reaction is one of the most important reactions in astrophysics. At Kyushu University Tandem accelerator Laboratory (KUTL), a high detective efficiency measurement has been made by adopting inverse kinematics: 12C beam is injected on windowless 4He gas target. In this experiment, a powerful background reduction system is necessary. We describe the effectiveness of the background system consisting of recoil mass separator, a long time chopper, and new movable slits. [ABSTRACT FROM AUTHOR]

Presents research discovering new discrepancies in pd radiative capture and pd breakup. Incidence of a vertically polarized beam from the RCNP cyclotron on a liquid nitrogen target; Use of a large acceptance spectrometer for detecting recoils in the vertical and horizontal planes; Relation between Axx≈Ayy and the large discrepancy in Axx that exists at the 140 MeV.

We found strong evidence for the existence of supersymmetry, by studying the odd-odd nucleus [sup 196]Au using the [sup 197]Au(↘,t), [sup 197]Au(p,d) and [sup 198]Hg(↘, α) transfer reactions. High resolution [sup 196]Pt(p,d) [sup 195]Pt and [sup 196]Pt(↘,t) [sup 195]Pt transfer experiments performed in parallel yielded at the same time an improved level scheme of [sup 195]Pt. Using extended supersymmetry, a single fit of the six parameter eigenvalue expression with only 6 free parameters A, B, B', C, D and E yielded a complete description of all observed low-lying excited states in the four different nuclei forming the supermultiplet. The detailed comparison of the transfer amplitudes for the states up to 500 keV in the odd-odd member of the supermultiplet [sup 196]Au using a semi-microscopic transfer operator, provides then evidence that this description is correct. For more detail see: A. Metz, et al., Phys. Rev. Lett. 83, 1542 (1999) and Phys. Rev. [ABSTRACT FROM AUTHOR]

To improve the flow rate of about 4.5.10[sup 16]&Drarr;/s a new dissociator based on a microwave discharge at 2.45 GHz has been developed and installed into the HERMES Atomic Beam Source. The long term stability was found to be excellent. Compared with the Radio-Frequency dissociator (RFD) used so far the intensity was increased by 15% although the sextupole magnet system has been optimized for the RF-dissociator. Furthermore the Carrier Jet method was tested, a new method of beam formation based on an expanded beam surrounded by an overexpanded carrier jet. Since there was a large deviation between the measurements and the results of the NavierStokes calculations Monte-Carlo simulations were performed. The results agree well with the measurements, showing that the method used in ref. does not provide a realistic description of beam formation in this flow range, in particular concerning the diffusive mixture of the two beams. [ABSTRACT FROM AUTHOR]