Commissioning has been completed at the China Spallation Neutron Source (CSNS), the country’s first pulsed spallation neutron source and the fourth in the world. The facility will provide scientists with a world-leading platform for studies in fields such as materials science and technology, life sciences, and new energy, etc.

The announcement of completion was made on March 25, at the CSNS Technology Assessment and Acceptance Meeting, held at the Dongguan Branch of the Institute of High Energy Physics, Chinese Academy of Sciences (IHEP), Guangdong Province.

An expert review committee consisting of 18 scientists from institutions including the University of Science and Technology of China, China Institute of Atomic Energy, National Natural Science Foundation of China, and Tsinghua University participated in the meeting, led by CAS Academician ZHAN Wenlong.

The review committee conducted an on-site inspection and listened to reports on the status of CSNS, then concluded that all the parameters of the facility have met their acceptance goals. The commissioning was faster than expected, and the highest proton to neutron conversion efficiency at the target reached the level of the world’s most advanced machines.

The review committee agreed that CSNS has passed the technology acceptance test, and recommended that the project strive to reach stable operation as soon as possible. They also recommended that, now that the CSNS Phase-I project has passed the acceptance test, work should start on the CSNS Phase-II project immediately, to build more state-of-the-art neutron instruments and increase the beam power.

CSNS has made a series of significant innovative technology achievements in accelerators, target station and instruments. Over 90% of the equipment was manufactured in China, which has greatly enhanced the country’s experience and innovation capacity in related industrial technology, especially in fields like magnets, power supplies, neutron detectors and electronics.

CSNS has also pushed forward research into high-intensity proton accelerators and neutron scattering in China. For example, 25 Hz AC resonant excitation large-scale dipole and quadrupole magnets and their power supplies were successfully developed in China for the first time, as well as liquid hydrogen moderators.

The CSNS project is led by IHEP, with a budget of 2.3 billion RMB. It is composed of an 80 MeV H¯ linac, a 1.6 GeV rapid cycling synchrotron (RCS), and a target station with 3 initial instruments for neutron scattering research. Starting in September 2011, the CSNS team has spent more than 6 years in the project construction, and has finished the facility and infrastructure construction.

A "super microscope" for looking into the microstructure of materials, the CSNS has a wide range of application prospects, including in life sciences, physics, chemistry, resources and the environment, and new energy. It will become a core part of the national science and technology industry innovation center currently being developed in Guangdong Province, and will make significant contributions to the development of technology and industry in the Guangdong-Hong Kong-Macau Greater Bay Area.

The first neutron beam was obtained at CSNS on August 28, 2017. In November 2017, a joint beam commissioning of the accelerators, target station and instruments was performed at the repetition rate of 25 Hz, with a stable beam power of above 10 kW, meeting the acceptance goal. During the Spring Festival holiday in February 2018, the CSNS team worked overtime and continued to perform commissioning. Sample experiments were successfully conducted using the initial three neutron instruments - the General-Purpose Powder Diffractometer (GPPD), Small-Angle Neutron Scattering instrument (SANS), and multi-purpose reflectometer (MR). Two high-level user sample experiments have now been completed at the GPPD, and it is expected that the facility will soon be widely used by domestic and international researchers.