In July 2000, Lu Yongxiang, President of the Chinese Academy of Sciences, visited the British Spallation Neutron Source ISIS during his visit to the UK.

ISIS has an average of 1,500 users per year and conducts more than 700 experiments on nearly 20 neutron scattering spectrometers. The Rutherford Laboratory, which built ISIS, publishes 500 high-level related papers every year and has already become a world-class laboratory.

After returning to China, Lu Yongxiang asked the Chinese Academy of Sciences to demonstrate the feasibility of building a spallation neutron source in my country. Such a large scientific platform is very important for improving the country's scientific and technological innovation capabilities. China needs it so much!

From February 18 to 20, 2001, according to the instructions of President Lu and other leaders, the Chinese Academy of Sciences held the Xiangshan Conference (the 157th) with the theme of "The Development of Neutron Science in the 21st Century". At the meeting, neutron scattering at home and abroad was introduced. The progress of research was discussed, and the idea of ??building a "sparse neutron source" in my country was discussed.

On May 8-9, 2001, the first academician consultation seminar on China Spallation Neutron Source Research was held. The meeting conducted an in-depth discussion on the necessity of building a "China Spallation Neutron Source" and suggested that the "China Spallation Neutron Source"

Conduct further investigation into the advancement and feasibility of the "fission neutron source".

On August 26-27, 2001, the second academician consultation seminar on China Spallation Neutron Source Research was held. The meeting heard special reports from experts from the Chinese Academy of Sciences and overseas experts, and approved the construction of a 25Hz, 100kW China Spallation Neutron Source.

CSNS scheme.

After the meeting, a project proposal for the construction of the China Spallation Neutron Source CSNS was submitted.

On December 31, 2001, leaders such as Lu Yongxiang and Bai Chunli of the Chinese Academy of Sciences listened to reports from the Institute of Physics and the Institute of High Energy and comments from overseas experts, and agreed to launch the conceptual design of the "China Spallation Neutron Source CSNS".

It is estimated that there are more than 1,900 potential users of spallation neutron sources in my country.

From April 22 to 26, 2002, the first international demonstration meeting of China's Spallation Neutron Source Target Station and Moderator was held in Beijing. The most senior scientists from several major spallation neutron sources in the world attended the meeting.

.

In July 2002, the important direction project of the Knowledge Innovation Project of the Chinese Academy of Sciences "Innovative Research on Key Technologies of Multidisciplinary Platform Spallation Neutron Source" was launched (completed in July 2004).

In April 2003, the Ministry of Science and Technology’s key international scientific and technological cooperation project “Sparse Neutron Source for Multidisciplinary Applications” was launched (completed in May 2004).

From July 26 to 31, 2004, in order to teach the basic knowledge of neutron scattering and cultivate potential users, the Institute of Physics held the first summer training course on neutron scattering, with 109 registrations.

From August 4 to 6, 2004, the first multidisciplinary application seminar on spallation neutron sources was held at the Institute of Physics. More than 180 experts, scholars and graduate students attended the meeting.

The meeting approved the first phase construction plan of five neutron scattering spectrometers proposed by the project team. Two users proposed to build two spectrometers by themselves with less than 10 million yuan in funding from the project team.

The meeting decided to establish the Neutron Scattering Users Alliance and determined the user work regulations.

On October 15-16, 2004, at the 25th Sino-US High Energy Physics Cooperation Joint Committee Meeting, four cooperation projects related to spallation neutron sources were included in the Sino-US High Energy Physics bilateral cooperation plan for the first time.

On December 8, 2004, the Institute of Physics held the "Institute of Physics Spallation Neutron Source Users Seminar". The meeting decided to establish the "Institute of Physics Spallation Neutron Source Users Expert Group" and determined the list of users of the expert group.

On June 1, 2005, the Planning Bureau of the Chinese Academy of Sciences organized an expert review meeting for the CSNS project proposal.

An expert group composed of 19 experts including Academician Wei Baowen listened to the overall report and 3 sub-reports of the project team.

Experts attending the meeting fully affirmed the great scientific significance of CSNS construction and believed that the plan to build a spallation neutron source with a beam power of 100kW and a repetition frequency of 25Hz proposed in the project proposal took into account user needs, investment intensity, construction The period and technical difficulty are proposed in line with my country's national conditions.

The Chinese Academy of Sciences organized relevant forces from the Institute of Physics and the Institute of High Energy to conduct preliminary research on the scheme design and key technologies for about three years, laying the foundation for the construction of CSNS.

Taking into account the rapid development of spallation neutron sources internationally and the increasingly urgent domestic demand for spallation neutron sources, the CSNS project should be established as soon as possible in accordance with the national major scientific project approval procedures.

On June 2, 2005, the President's Office Meeting of the Chinese Academy of Sciences agreed to submit CSNS to the National Development and Reform Commission, and decided to provide 30 million yuan in funding for preliminary prefabrication research before CSNS completes the project.

On July 19, 2005, the State Council Science and Education Leading Group approved in principle the construction of nine major scientific installations in the next five years, with an estimated investment of 6 billion yuan, of which the cost of CSNS is 1.2 billion yuan.

From July 27 to 29, 2005, the second multidisciplinary application seminar on spallation neutron sources was held at the Institute of Physics. More than 170 experts, scholars and graduate students attended the meeting.

Participants gained a better understanding of neutron scattering technology, spectrometers and applications, the construction concept of CSNS, and the broad prospects of neutron scattering applications in various fields of scientific research in my country.