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
Vanadium alloys are considered as the promising first wall and structure materials of the future fusion reactors owing to their perfect low neutron-induced radioactivity and good high temperature performance. Helium r...Vanadium alloys are considered as the promising first wall and structure materials of the future fusion reactors owing to their perfect low neutron-induced radioactivity and good high temperature performance. Helium retention and thermal desorption behaviors are key issues for the applications of vanadium alloys in fusion reactors since helium can be produced by helium discharge cleaning and neutron transmutation. A. van Veen groupt investigated helium trapping and thermal desorption mechanisms in vanadium alloys by using 1 keV helium ion irradiation to the fluence of 10^13～10^14He/cm^2, and the influenee of pre-annealing treatments on helium trapping. Two group of peaks were found at the thermal helium desorption spectrum. They thought one was due to helium-vacancyimpurity clusters and the other was corresponding to helium trapping into pre-existing traps, such as fine-size precipitates.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:
文摘Vanadium alloys are considered as the promising first wall and structure materials of the future fusion reactors owing to their perfect low neutron-induced radioactivity and good high temperature performance. Helium retention and thermal desorption behaviors are key issues for the applications of vanadium alloys in fusion reactors since helium can be produced by helium discharge cleaning and neutron transmutation. A. van Veen groupt investigated helium trapping and thermal desorption mechanisms in vanadium alloys by using 1 keV helium ion irradiation to the fluence of 10^13～10^14He/cm^2, and the influenee of pre-annealing treatments on helium trapping. Two group of peaks were found at the thermal helium desorption spectrum. They thought one was due to helium-vacancyimpurity clusters and the other was corresponding to helium trapping into pre-existing traps, such as fine-size precipitates.
