Welton R F, Han B X, Stockli M P, Murray S N, Pennisi T R, Stinson C, Barnett W, Aleksandrov A, Piller M, Saethre R, Kang Y, Zhukov A
Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37830-6471, USA.
Rev Sci Instrum. 2020 Jan 1;91(1):013334. doi: 10.1063/1.5128508.
The U.S. Spallation Neutron Source (SNS) is a state-of-the-art neutron scattering facility delivering the world's most intense pulsed neutron beams to a wide array of instruments, which are used to conduct investigations in many fields of engineering, physics, chemistry, material science, and biology. Neutrons are produced by spallation of liquid Hg by the bombardment of short (∼1 µs), intense (∼35 A) pulses of protons delivered at 60 Hz by an accumulator ring which is fed by a high-intensity, 1 GeV, H LINAC (linear accelerator). This facility has operated nearly continuously since 2006 but has recently undergone a 4-month maintenance period, which featured a complete replacement of the 2.5 MeV injector feeding the LINAC. The new injector was developed at ORNL in an off-line beam test facility and consists of an ion source, low energy beam transport, and a Radio Frequency Quadrupole (RFQ). This report first describes the installed configuration of the new injector detailing the ion source system. The first beam current, RFQ transmission, emittance, and energy measurements from the injector installed on the SNS are reported. These data not only show a significant performance improvement for our existing facility but will also make accessible the higher beam current requirements for future SNS upgrade projects: the proton power upgrade and second target station.
美国散裂中子源（SNS）是一个先进的中子散射设施，它为一系列仪器提供世界上最强的脉冲中子束，这些仪器用于在工程、物理、化学、材料科学和生物学等许多领域进行研究。中子是通过由高强度1 GeV的H直线加速器（LINAC）馈送的累积环以60 Hz的频率提供的短（约1微秒）、强（约35 A）质子脉冲轰击液态汞产生散裂而产生的。该设施自2006年以来几乎一直在运行，但最近经历了为期4个月的维护期，其中主要对馈入LINAC的2.5 MeV注入器进行了全面更换。新的注入器是在橡树岭国家实验室的离线束流测试设施中开发的，由一个离子源、低能束流传输装置和一个射频四极杆（RFQ）组成。本报告首先描述新注入器的安装配置，详细介绍离子源系统。报告了安装在SNS上的注入器的首次束流、RFQ传输、发射度和能量测量结果。这些数据不仅显示了我们现有设施的显著性能提升，也将满足未来SNS升级项目（质子功率升级和第二个靶站）对更高束流的要求。
