Background The China Spallation Neutron Source incorporates a rapid cycling synchrotron(RCS)that operates by accumulating protons at 80 MeV and subsequently accelerating them to 1.6 GeV within a time span of 20 ms.The...Background The China Spallation Neutron Source incorporates a rapid cycling synchrotron(RCS)that operates by accumulating protons at 80 MeV and subsequently accelerating them to 1.6 GeV within a time span of 20 ms.The beam is guided to striking the tungsten target for neutron source.Purpose As a space charge dominated machine,the RCS is subject to space charge effects and momentum spread,hereby influencing the tune spread.To address this issue,sextupole magnets,powered by two families of DC power supply,were initially employed to decrease the absolute value of chromaticity and to control the tune spread.The head-tail instability has been observed during the RCS beam commissioning.Method The beam tests and simulations were conducted,revealing that tuning the chromaticity proved to be an effective mitigation strategy.However,to achieve better control over the tune spread and further suppress the instability,the DC sextupole field has been upgraded to an AC sextupole field,aiming to provide dynamic for controlling the chromaticity over an acceleration cycle.Results and conclusion Thanks to the upgraded of AC field,the instability has been fully mitigated with beam power of 100 kW and the transmission in the RCS has been improved by~2%from 96 to 98%.With help of AC sextupole at present,the beam power in the RCS is increased to 140 kW.展开更多
The China Spallation Neutron Source (CSNS) is an accelerator-based facility. The accelerator of CSNS consists of a low energy linac, a Rapid Cycling Synchrotron (RCS) and two beam transport lines. The overall physics ...The China Spallation Neutron Source (CSNS) is an accelerator-based facility. The accelerator of CSNS consists of a low energy linac, a Rapid Cycling Synchrotron (RCS) and two beam transport lines. The overall physics design of CSNS accelerator is described, including the design principle, the choice of the main parameters and design of each part of accelerators. The key problems of the physics design, such as beam loss and control, are also discussed. The interface between the different parts of accelerator, as well as between accelerator and target, are introduced.展开更多
基金supported by the National Natural Science Foundation of China(Project:U1832210)the Guangdong Basic and Applied Basic Research Foundation,China(Project:2021B1515140007).
文摘Background The China Spallation Neutron Source incorporates a rapid cycling synchrotron(RCS)that operates by accumulating protons at 80 MeV and subsequently accelerating them to 1.6 GeV within a time span of 20 ms.The beam is guided to striking the tungsten target for neutron source.Purpose As a space charge dominated machine,the RCS is subject to space charge effects and momentum spread,hereby influencing the tune spread.To address this issue,sextupole magnets,powered by two families of DC power supply,were initially employed to decrease the absolute value of chromaticity and to control the tune spread.The head-tail instability has been observed during the RCS beam commissioning.Method The beam tests and simulations were conducted,revealing that tuning the chromaticity proved to be an effective mitigation strategy.However,to achieve better control over the tune spread and further suppress the instability,the DC sextupole field has been upgraded to an AC sextupole field,aiming to provide dynamic for controlling the chromaticity over an acceleration cycle.Results and conclusion Thanks to the upgraded of AC field,the instability has been fully mitigated with beam power of 100 kW and the transmission in the RCS has been improved by~2%from 96 to 98%.With help of AC sextupole at present,the beam power in the RCS is increased to 140 kW.
文摘The China Spallation Neutron Source (CSNS) is an accelerator-based facility. The accelerator of CSNS consists of a low energy linac, a Rapid Cycling Synchrotron (RCS) and two beam transport lines. The overall physics design of CSNS accelerator is described, including the design principle, the choice of the main parameters and design of each part of accelerators. The key problems of the physics design, such as beam loss and control, are also discussed. The interface between the different parts of accelerator, as well as between accelerator and target, are introduced.
