A nuclear astrophysics experiment was performed at CRIB (CNS low-energy Radioactive-Ion Beam separator)on Mar. 2011. The goal of this experiment is to study the reaction rate of 18Ne(,p)21Na reaction, which mightbe a ...A nuclear astrophysics experiment was performed at CRIB (CNS low-energy Radioactive-Ion Beam separator)on Mar. 2011. The goal of this experiment is to study the reaction rate of 18Ne(,p)21Na reaction, which mightbe a key breakout reaction from the hot CNO cycle to rp-process in X-ray burst and nova. Yet its reaction rate ispoorly known.Explosive hydrogen burning is thought to be the main source of energy generation and a source of nucleosynthesisin X-ray burst and nova[1;2]. For example, XRBs are characterized by a sudden increase of X-ray emission withinonly a few seconds to a total energy output of about 1040 ergs, which is observed to repeat with some regularity.The recurrence time for single bursts can range from hours to days at the typical temperature of 0.4～2 GK. Thebursts have been interpreted as being generated by thermonuclear runaway on the surface of a neutron star thataccretes H- and He-rich material from a less evolved companion star in a close binary system. As shown in Fig. 1,under its typical temperature, the hydrogen burning in X-ray burst occurs from the hot CNO cycle:展开更多
We have derived new thermonuclear 64Ge(p, )65As and 65As(p, )66Se reaction rates based on recently evaluatedproton separation energies[1] and large-scale shell model (LSSM) calculation. The precisely measured or evalu...We have derived new thermonuclear 64Ge(p, )65As and 65As(p, )66Se reaction rates based on recently evaluatedproton separation energies[1] and large-scale shell model (LSSM) calculation. The precisely measured or evaluatedproton separation energies of Sp(65As) and Sp(66Se), are (90±85) keV and (1720±310) keV, respectively. Weutilized one-zone post-processing type I X-ray burst model[2] to investigate the astrophysical impact of our newrates. We found that the new experimental Sp(65As), resonant energies and spectroscopic factors estimated fromLSSM significantly affects the productions of nuclide in the range of 64≤A≤110 about one to ten times comparedto currently available JINA data sets, REACLIB[3].展开更多
Proton resonant states in 18Ne have been investigated by the resonant scattering of 17F+p with a 17F beambombarding a thick H2 gas target. Several resonances have been observed. In particular, the astrophysically cruc...Proton resonant states in 18Ne have been investigated by the resonant scattering of 17F+p with a 17F beambombarding a thick H2 gas target. Several resonances have been observed. In particular, the astrophysically crucialstate 6.15 MeV was observed as a spin-parity assignment of 1?? with high statistics. The groove-like structureobserved in this work is completely different with previous peak one[1]. The confirmation of 1?? on a firm groundclarified this significant discrepancy. In addition, a new state was observed at Ex = 6.85 MeV with a tentativespin assignment of 0, which could be the mirror state of 6.88 MeV, 0?? in 18O, or a bandhead state (0+) of thesix-particle four-hole (6p-4h) band[2,3]. The resonant parameters have been determined by an R-matrix analysis ofthe excitation functions.展开更多
Isochronous mass spectrometry in storage rings is a successful technique for the precision mass measurements ofthe nuclides with half-lives down to tens of microseconds[1]. Since the isochronous condition =t greatly r...Isochronous mass spectrometry in storage rings is a successful technique for the precision mass measurements ofthe nuclides with half-lives down to tens of microseconds[1]. Since the isochronous condition =t greatly reducesthe influence of the velocity difference on the ion revolution periods, the revolution period difference ΔT =T ??TRof a stored ion with respect to a reference time TR is directly related to its mass-to-charge ratio difference Δ(m=q),written in the first order as:展开更多
文摘A nuclear astrophysics experiment was performed at CRIB (CNS low-energy Radioactive-Ion Beam separator)on Mar. 2011. The goal of this experiment is to study the reaction rate of 18Ne(,p)21Na reaction, which mightbe a key breakout reaction from the hot CNO cycle to rp-process in X-ray burst and nova. Yet its reaction rate ispoorly known.Explosive hydrogen burning is thought to be the main source of energy generation and a source of nucleosynthesisin X-ray burst and nova[1;2]. For example, XRBs are characterized by a sudden increase of X-ray emission withinonly a few seconds to a total energy output of about 1040 ergs, which is observed to repeat with some regularity.The recurrence time for single bursts can range from hours to days at the typical temperature of 0.4～2 GK. Thebursts have been interpreted as being generated by thermonuclear runaway on the surface of a neutron star thataccretes H- and He-rich material from a less evolved companion star in a close binary system. As shown in Fig. 1,under its typical temperature, the hydrogen burning in X-ray burst occurs from the hot CNO cycle:
基金Auspices of Ministry of Science and Technology of China (Talented Young Scientist Program), China PostdoctoralScience Foundation (2014M562481).
文摘We have derived new thermonuclear 64Ge(p, )65As and 65As(p, )66Se reaction rates based on recently evaluatedproton separation energies[1] and large-scale shell model (LSSM) calculation. The precisely measured or evaluatedproton separation energies of Sp(65As) and Sp(66Se), are (90±85) keV and (1720±310) keV, respectively. Weutilized one-zone post-processing type I X-ray burst model[2] to investigate the astrophysical impact of our newrates. We found that the new experimental Sp(65As), resonant energies and spectroscopic factors estimated fromLSSM significantly affects the productions of nuclide in the range of 64≤A≤110 about one to ten times comparedto currently available JINA data sets, REACLIB[3].
文摘Proton resonant states in 18Ne have been investigated by the resonant scattering of 17F+p with a 17F beambombarding a thick H2 gas target. Several resonances have been observed. In particular, the astrophysically crucialstate 6.15 MeV was observed as a spin-parity assignment of 1?? with high statistics. The groove-like structureobserved in this work is completely different with previous peak one[1]. The confirmation of 1?? on a firm groundclarified this significant discrepancy. In addition, a new state was observed at Ex = 6.85 MeV with a tentativespin assignment of 0, which could be the mirror state of 6.88 MeV, 0?? in 18O, or a bandhead state (0+) of thesix-particle four-hole (6p-4h) band[2,3]. The resonant parameters have been determined by an R-matrix analysis ofthe excitation functions.
文摘Isochronous mass spectrometry in storage rings is a successful technique for the precision mass measurements ofthe nuclides with half-lives down to tens of microseconds[1]. Since the isochronous condition =t greatly reducesthe influence of the velocity difference on the ion revolution periods, the revolution period difference ΔT =T ??TRof a stored ion with respect to a reference time TR is directly related to its mass-to-charge ratio difference Δ(m=q),written in the first order as:
