In July 2000, Mr. Lu Yongxiang, President of Chinese Academy of Sciences (CAS), visited ISIS, the UK's source of scattered neutrons, which has an average of 1,500 users per year, conducts more than 700 experiments on nearly 20 neutron scattering spectrometers, and has long been a world-class laboratory, with the Rutherford Laboratory, where ISIS is constructed, publishing 500 high-quality related papers every year. Upon his return to China, Lu Yongxiang asked CAS to demonstrate the feasibility of building the Scattered Neutron Source (SNS) in China. Such a large scientific platform is very important for improving the country's scientific and technological innovation capability, which is too much needed in China!
On February 18-20, 2001, according to the instructions of President Lu and other leaders, CAS held the Xiangshan Conference (the 157th) with the theme of "Development of Neutron Science in the 21st Century", at which the progress of neutron scattering research at home and abroad was introduced, and the progress of the construction of the "Scattered Neutron Source" in China was discussed. At the meeting, the progress of neutron scattering research in China and abroad was introduced, and the idea of building a "Scattered Neutron Source" in China was discussed.
On May 8-9, 2001, the First Academician's Consultation Workshop on China's Scattered Neutron Source was held, in which the necessity of constructing China's Scattered Neutron Source was discussed in depth, and further investigations on the advancement and feasibility of China's Scattered Neutron Source were suggested. It was recommended that further research should be carried out to investigate the advancedness and feasibility of the "China Scattered Neutron Source".
On August 26-27, 2001, the Second Academician's Consultation Workshop on China Scattered Neutron Source (CSNS) was held, which listened to the presentations of experts from the Chinese Academy of Sciences (CAS) and overseas experts, and adopted the proposal of constructing CSNS at 25 Hz and 100 kW. The project proposal for the construction of the China Scattered Neutron Source CSNS was submitted after the meeting.
On December 31, 2001, Lu Yongxiang, Bai Chunli and other leaders of the Chinese Academy of Sciences (CAS) listened to the reports of the Institute of Physics (IP) and the Institute of High Energy (IHE), as well as the comments of the overseas experts, and agreed to launch the conceptual design of the China Scattered Neutron Source (CSNS). It is estimated that there are more than 1,900 potential users of CSNS in China.
The First International Symposium on China Scattered Neutron Source (CSNS) Target Station and Moderator was held on April 22-26, 2002, in Beijing, with the participation of top scientists from the world's major scattered neutron sources.
July 2002, the "Innovative Research on Key Technologies of the Fractured Neutron Source on Multidisciplinary Platforms", an important direction project of the Knowledge Innovation Project of the Chinese Academy of Sciences (CAS), was initiated (concluded in July 2004).
In April 2003, the International Science and Technology Cooperation Program of the Ministry of Science and Technology (MOST) was initiated (completed in May 2004) for the "Multidisciplinary Application of Fractured Neutron Source".
July 26-31, 2004, in order to teach the basics of neutron scattering and cultivate potential users, IUPAC held the first Summer Course on Neutron Scattering, with 109 registrants.
August 4-6, 2004, the First Multidisciplinary Application Workshop on the Scattered Neutron Source was held at the Institute of Physics, with more than 180 experts, scholars and postgraduates attending the meeting. The meeting passed the construction plan of five neutron scattering spectrometers in the first phase proposed by the project team, and two users proposed to build two spectrometers by themselves under the premise that the project team would fund less than 10 million yuan. The meeting decided to set up the Neutron Scattering Users' Union and determined the working regulations of the users.
On October 15-16, 2004, at the 25th Joint Committee Meeting of the U.S.-China Collaboration in High Energy Physics, four collaborative projects related to the Scattered Neutron Source (SNS) were included in the U.S.-China Bilateral Collaboration Program in High Energy Physics for the first time.
On December 8, 2004, the Institute of Physics held the "User Seminar on Scattered Neutron Source of the Institute of Physics", which decided to set up the "User Expert Group of the Institute of Physics on the Scattered Neutron Source", and determined the list of the personnel of the User Expert Group. On June 1, 2005, the Planning Bureau of CAS organized an expert review meeting for CSNS project proposals. The expert group composed of 19 experts, including Academician Wei Baowen, listened to the overall report and three sub-reports of the project team. The experts fully affirmed the great scientific significance of the construction of CSNS, and considered that the proposal of building a 100kW beam power and 25Hz repetition frequency spallation neutron source is in line with China's national conditions, taking into account the needs of the users, the investment intensity, the construction period, and the technical difficulties. CAS has organized relevant forces from the Institute of Physics and the Institute of High Energy to carry out about three years of preliminary research on the design of the scheme and key technologies, laying the foundation for the construction of CSNS. Considering the rapid development of the international scattered neutron source and the more and more urgent domestic demand for the source, CSNS should be established as soon as possible in accordance with the procedure for establishing national large-scale scientific projects.
On June 2, 2005, the presidential office of CAS agreed to submit the CSNS to the National Development and Reform Commission (NDRC) and decided to provide 30 million yuan of funding for the preliminary pre-fabrication study of the CSNS before the completion of the project.
On July 19, 2005, the State Council's Leading Group of Science and Education approved in principle the construction of nine major scientific devices in the next five years, with an estimated investment of 6 billion yuan, of which the cost of CSNS is 1.2 billion yuan.
July 27-29, 2005, the Second Workshop on Multidisciplinary Applications of the Scattered Neutron Source (CSNS) was held at the Institute of Physics (IOP), with more than 170 experts, scholars and postgraduates attending the meeting. The 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 China.
On November 27, 2005, the Planning Bureau and the Foundation Bureau of CAS organized an expert review meeting for the CSNS pre-production study, which affirmed the importance and necessity of the pre-production study and agreed to start the CSNS pre-production study.
On February 27, 2006, the CSNS Target Station Spectrometer Engineering Center (Preparation) of Institute of Physics, Chinese Academy of Sciences (IPS) was listed.
April 25-27, 2006, the International Symposium on CSNS Accelerator Engineering Design was held at IHE, which comprehensively evaluated the engineering design of all parts of the gas pedal.
On July 31, 2006, the Third Multidisciplinary Symposium on Applications of the Scattered Neutron Source was held at the Institute of Physics. The meeting invited the project leaders of the Scattered Neutron Source (SNS) in the United States, Japan, and the United Kingdom to introduce the international dynamics, and invited the users to put forward their requirements on the performance of the CSNS for the improvement of the overall design and the parameters of the spectrometer.
The 281st Xiangshan Conference on "Frontier Scientific Issues at the Intersection of Synchrotron Radiation and Neutron Scattering" was held at CAS on August 3-4, 2006, with 54 experts and scholars from 20 institutions in China and the United States. The meeting focused on the intersection of synchrotron radiation and neutron scattering technologies, the intersection of the Scattered Split Neutron Source (SSNS) and the Reactor Neutron Source (RNS), and the intersection of synchrotron radiation and neutron scattering technologies with the fields of condensed matter physics, soft matter and life sciences, and imaging and medicine. The experts from different fields expressed their views on giving full play to the role of the SCR as a multidisciplinary application platform, and reached many important ****recognitions and put forward many good suggestions.
On November 12-15, 2006, the First Sino-US Workshop on Neutron Scattering Technology was held in Beijing, which was co-sponsored by the National Natural Science Foundation of the United States (NSF), the China Institute of Atomic Energy Sciences (CIAES), and the Chinese Academy of Sciences (CAS)***. Atomic Energy Research Institute, China Institute of Atomic Energy Science, Institute of Physics, Institute of High Energy, Institute of Chemistry, Institute of Metals, Peking University, Tsinghua University and other eight countries, laboratory leaders, experts, scholars, graduate students *** more than 160 people attended the meeting.
On February 13, 2007, CAS and the People's Government of Guangdong Province signed the Memorandum of Cooperation between the Chinese Academy of Sciences and the People's Government of Guangdong Province on the China Scattered Neutron Source Project and the National Laboratory of the Scattered Neutron Source in Dongguan, Guangdong Province, whereby the two sides will *** apply to the State for the construction of China's first and world-class integrated experimental device for pulsed neutron science in Dongguan, Guangdong Province.
In February 2007, new progress was made in the development of CSNS ion source. As a pre-injector, the negative hydrogen ion source is one of the key equipments of the whole scattered neutron source device, and the beam current intensity it provides directly affects the final achieved current intensity on the scattering target. By digesting and absorbing the information obtained from ISIS, IASP designed and fabricated the Penning source, the core component of the source, and conducted a series of tests under the guidance and assistance of ISIS experts, who warmly praised and affirmed the test results.
In February 2007, the development of the aluminum stranded wire and coil prototype for the main magnet of the CSNS was successful.The main magnet in the CSNS RCS is excited by a 25Hz sinusoidal AC source with DC bias, and the use of hollow, water-cooled aluminum stranded wire coils is the most effective method. The Institute of High Energy (IHE), in collaboration with Shanghai Klin Technology Co., Ltd, Lanzhou Institute of Near East Technology Co., Ltd. and Hefei Institute of Plasma Polyenergy Electrophysics Technology Co., Ltd. have been developing aluminum stranded wire diode magnet test coils, respectively. After collaboration with a number of aluminum conductor production units, two domestic trial production of hollow water-cooled aluminum stranded wire. The aluminum stranded wire coils successfully developed by the three cooperative units have met the design requirements after preliminary testing, solving one of the core problems in the development of the main magnet of the RCS ring of the Scattered Neutron Source. A number of technologies and processes obtained in the development process have played a role in promoting and facilitating the development of related technologies in China.
On April 25, 2007, CSNS held a scientific report meeting, in which Fang Shouxian, academician of Chinese Academy of Sciences, and Wei Jie, head of CSNS project, made a report on the safety and application of the Scattered Neutron Source. Experts pointed out that CSNS is based on a new generation of gas pedals, does not require nuclear materials, its power comes from electricity, its radiation is controlled in the environmentally safe range, and it is a world-class safety device. Living near the CSNS for one year, the radiation exposure of the residents is only equivalent to taking an airplane. On April 26, 2007, the Guangdong Dongguan Neutron Science Center was officially opened in the Songshan Lake Science and Technology Industrial Park, marking the official start of the construction of China's first Scattered Neutron Source project and the Dongguan Scattered Neutron Source National Laboratory.
The 18th International Conference on Advanced Neutron Sources (ICANS) was held in Dongguan, Guangdong Province, from April 26 to 29, 2007, with the participation of about 100 foreign scientists, more than 100 domestic scientists as well as experts, scholars and engineers in related fields. This is the first time that the International Conference on Advanced Neutron Sources is held in China, which is of great significance.
On May 1-3, 2007, the first review meeting of the International Advisory Board of the CSNS project was held at IHE, which is an important milestone in the construction of the CSNS project.
The CSNS has established the International Advisory Board (consisting of the International Science and Technology Advisory Board, the International Accelerator Advisory Board and the International Target Spectrometer Advisory Board) with reference to the international practice. The members of the Advisory Board are well-known international and domestic experts in related fields. As the first world-class strong current proton targeting facility in China, international experience is extremely important for the construction of China Scattered Fractured Neutron Source (CSNS). During the construction period, the International Advisory Board will regularly provide comments and advice on key scientific and technical issues in the construction and development of the project to mobilize and bring into full play the roles and enthusiasm of all parties, so as to ensure the smooth progress of the project. The meeting listened to the reports of the overall and various sub-systems, conducted a comprehensive review of the overall program and specific technical parameters of the CSNS, made directional suggestions on the overall indicators, gas pedal and target station spectrometer, and gave specific opinions on the next step.
On July 6, 2007, the evaluation meeting of CSNS project feasibility study engineering geological survey was held in Dalang Town, Dongguan City, Guangdong Province. Participants included the Institute of High Energy, the Institute of Physics, the Institute of Geology and Geophysics, the Dongguan Municipal Government and the city's Development and Reform Bureau, Planning Bureau, Science and Technology Bureau, Finance Bureau, Environmental Protection Bureau, Construction Bureau, Land Bureau, Songshan Lake Hi-tech Development Zone Administrative Committee, and Dalang Township Government. The evaluation team consisted of 7 experts in geosurveying and 11 representatives*** from the Institute of High Energy and Physics. The Institute of Geology and Geophysics of the Chinese Academy of Sciences completed the engineering geological survey for the feasibility study of the CSNS project after more than two months of investigation. The group listened to the results report of the person in charge of the project, conducted on-site inspection and discussion, and examined and commented on the general report, annexes and corresponding drawings of the CSNS Feasibility Study Engineering Geological Survey Report submitted by the project team. The Panel is of the view that the pre-selected site proposed in the report is suitable for the construction of the CSNS project and that moderately weathered granite or metamorphic rocks have been selected as the foundation of the CSNS project. The report, with necessary modifications, can be used as the basis document for the next stage of program planning and design.
On December 2-4, 2007, commissioned by the National Development and Reform Commission (NDRC), the China International Engineering Consulting Corporation (CIEC) organized experts to evaluate the "China Scattered Fractured Neutron Source Project Proposal" declared by the Chinese Academy of Sciences (CAS). Fourteen experts from CICC, Chinese Academy of Sciences (CAS), Institute of Atomic Energy Sciences (IAES), Chinese Academy of Engineering Physics (CAEP), Tsinghua University (TU) and other organizations served as assessors of the evaluation team. The evaluation team listened to the reports on the overall situation of the project, scientific significance and user needs, construction program and key technologies, civil engineering, general facilities and environmental protection, quality of project funding and schedule management, and asked questions on the necessity of project construction, demand analysis, construction objectives, reasonableness of the program, reasonableness of the investment estimation, analysis of the project's benefits and risk analysis, and so on. After talks, exchanges of opinions and internal discussions, the evaluation team concluded that "the Scattered Neutron Source is a large-scale multidisciplinary **** research platform, which is very important for the development of national science and technology, and the construction of the Scattered Neutron Source in China is very necessary and timely, and it is recommended that the project be launched as soon as possible. After years of hard work and intensive work, the project team has achieved very good results, which are well reflected in the project proposal. The experts believe that the technical program of the project is reasonable and feasible, in line with China's national conditions, and meets the requirements of the evaluation. The experts also put forward very useful suggestions for the next step of the Scattered Neutron Source project.
On May 31, 2008, the CSNS diode magnet power supply prototype was successfully tested at full load on a single mesh B-iron resonant network, with a loading current of 1160+860sin(50 t), of which 1160 amperes DC, 860 amperes AC, and an AC frequency of 25 Hz. During the process of energizing the power supply, the resonance system worked normally, and the various components were subjected to the designed voltage . This is the first time full load operation has been achieved since February 22, 2008 after the resonant load connections were completed. The dipole magnet resonant power supply system is an important research project of CSNS pre-research, and this kind of high-power resonant power supply applied in particle gas pedal is successfully developed for the first time in China, marking a key step in the development of CSNS power supply and magnet prototype.
On June 5, 2008, the series resonant pulse high-voltage power supply prototype developed by CSNS Linear RF System in cooperation with China Academy of Atomic Energy Sciences was tested by the expert test group, and its main technical indexes have reached the design requirements, with the Q value of the resonant reactor greater than 350, and the power supply machine in the case of the speed control tube cathode high voltage of 66kV and high-frequency output power of 380kW, with the efficiency of 88%, stable and reliable operation. Efficiency of 88%, stable and reliable, the expert acceptance group unanimously agreed to pass the product acceptance. This project is the key project of CSNS pre-study, which is based on the new pulse high-voltage power supply program independently proposed by China's RF experts, and it is the first time in the world that the traditional capacitance-inductance series resonance principle is combined with the modulator (electronic switch) to provide pulse high-voltage for the speed control tube. It has the advantages of simple structure, safety and reliability, low failure rate, easy maintenance and so on. At present, this new program has not been reported at home and abroad using similar equipment structure. The process is difficult because of the reactor inductance and capacitor capacitance precision requirements are very high, the resonant capacitor tangent loss control in 0.04%, high Q value of high-power reactor development, the production process is very sophisticated. This development project is a pioneering research work, all relying on the domestic technical basis and strength of independent research and development, which is an important milestone in the development of CSNS linear high-frequency power source.
On June 17, 2008, the CSNS environmental impact assessment expert review meeting organized by the State Ministry of Environmental Protection was held in Dongguan City, Guangdong Province. Ten experts from the Nuclear Safety and Environment Expert Committee of the Ministry of Environmental Protection (MEP), the Department of Safety Management of MEP, the Nuclear and Radiation Safety Center of MEP, and the Synchrotron Radiation National Laboratory in Hefei served as reviewers for the review team, with the Guangdong Provincial Environmental Protection Bureau (GDEPB), Dongguan Environmental Protection Bureau (EPB), the Environmental Protection Sub-bureau of Dalang Town, and the Guangdong Provincial Institute of Industrial Development (GDIID) attending the meeting. Wei Jie, the project manager of CSNS, introduced the general situation of the project, scientific significance and user needs, construction program and key technologies. Prof. Liu Yuanzhong from Tsinghua University, the compiler of the project EIR, reported on the environmental conditions and analysis of the environmental impacts during the construction period, the impacts of the construction project on the environment, radiation monitoring, radiation protection and safety management, and public participation. Participating experts inspected the proposed site in Dalang Town, Dongguan City, and asked questions on environmental impacts such as site address, seismicity, dose management target values, radiation source items, etc., and the project team defended the report. The expert group held that: "The report gives a clear and systematic description of the necessity of constructing the Scattered Fractured Neutron Source, the characteristics of the project and the related environmental impacts; the format and content of the report meet the requirements of the relevant national regulations, the compilation basis is sufficient, the purpose of the evaluation is clear, and the description of the identification and evaluation of the environmental impact factors is clear and comprehensive, which meets the requirements of environmental impact evaluation of the project; the project has a good impact on environmental impact evaluation; the project has a good impact on environmental impacts. evaluation requirements; the project's impact on the environment is acceptable conclusion credible".
The 3rd ACFA-HPPA Mini-workshop of Asia Future Accelerator Committee (AFAC) was held on July 17-19, 2008 at the Institute of High Energy. More than 40 representatives from J-PARC (Japan), KAERI (Korea), and IASP attended the workshop. The purpose of the workshop is to exchange the development status of strong current proton gas pedal in Asia, and hope to further strengthen the cooperation of Asian countries in this field through the discussion. Experts from J-PARC (Japan), KAERI (Korea) and IHE reported the progress of their respective research, and discussed in detail the topics of LINAC operation, RCS ring design and prefabrication research, and superconductivity technology, etc. The participants reached an agreement on further research cooperation. The participants reached a ****cognizance on further research cooperation, and the seminar was a complete success. At present, the initial success of J-PARC beam tuning in Japan will provide more reference and experience for the design and construction of China Scattered Neutron Source (CSN). Participating experts visited the CSNS key equipment pre-research results. The previous two workshops were held in KEK, Japan and KAERI, Korea.
On September 28, 2008, the National Development and Reform Commission (NDRC) formally approved the project proposal of the Scattered Neutron Source (CSNS). The overall scientific goal of the project is to build a world-class multidisciplinary research platform for neutron scattering and to form the National Center for Scattered Neutron Source (NCSC) after the completion of the project.