Author:Chen Hesheng† Zhang Chuang (Institute of High Energy Physics, Chinese Academy of Sciences)
This article is from Physics, No. 5, 2020
On January 19, 2020, Mr. Fang Shouxian, a famous accelerator physicist and academician of the Chinese Academy of Sciences, passed away in Beijing. Throughout his life, he has adhered to the forefront of accelerator science and technology research, and through extensive international cooperation, he has built a solid bridge for active cooperation between China and other countries in the field of accelerators, and made significant contributions to the sustainable development of China's high-energy physics and particle accelerator undertakings.
Sir left for a whole year, just this article, to send our condolences!
Fang Shouxian (1932.10.28—2020.1.19)
At the beginning of March 2019, Mr. Fang Shouxian suddenly suffered pneumonia after returning to Beijing after participating in the debugging and research of the proton therapy accelerator in Shanghai, fought tenaciously against the disease for more than 10 months, and calmly left the hospital on January 19, 2020. In the glorious years of 87 years, he used his life to fulfill the vow of "building a world-class high-energy accelerator for the motherland".
<h1 class="pgc-h-decimal" data-index="01" > seven under eight on the construction of The Beijing positron-negative electron collider</h1>
Fang Shouxian entered the Department of Physics of Shanghai Jiao Tong University in 1951 and transferred to the Department of Physics of Fudan University the following year, and has since formed an indissoluble relationship with physics. In 1955, he graduated from Fudan University and came to work at the Institute of Atomic Energy of the Chinese Academy of Sciences, where he was engaged in the design and research of high-energy accelerators. In the spring of 1957, under the leadership of Mr. Wang Ganchang, Fang Shouxian went to the Soviet Union, successively interned and worked at the Liebedev Institute of Physics and the Dubna Joint Institute of Nuclear Research, returned to the Institute of Atomic Energy at the end of 1960, continued to engage in accelerator theory research, and transferred from the first part of the Institute of Atomic Energy to the Institute of High Energy Physics of the Chinese Academy of Sciences in 1973. In his 65-year scientific research career, Fang Shouxian devoted himself to the research and construction of particle accelerators, and personally participated in and experienced the bumpy process of "seven up and seven down" of high-energy accelerators in the early 20 years.
In accordance with the concept of "manufacturing an appropriate high-energy accelerator" proposed in the twelve-year long-term plan for China's scientific development formulated in 1956, Fang Shouxian completed the design of a 2 GeV electron synchrotron under the guidance of Soviet experts. However, in the situation of the "Great Leap Forward" in 1958, this plan was criticized as "conservative and backward" and was discontinued. Subsequently, the 15 GeV proton synchrotron program was proposed in China, but it was "coldly treated" by Soviet experts, and reluctantly agreed to repair the magnet section of the original 7 GeV accelerator to increase the energy to 12 GeV. This kind of tinkering scheme is very unsatisfactory, let alone advanced, and has been resisted and rejected by our side.
At the end of 1959, the physics group led by Wang Ganchang proposed to build a medium-energy strong current accelerator with an energy of 450 MeV to carry out meson physics research. Fang Shouxian served as the person in charge of the theoretical design of this accelerator, and completed the preliminary design of the accelerator in half a year. However, due to the economic difficulties in the country at that time, the project soon survived in name only and was cancelled in 1963.
In 1968, the Institute of Atomic Energy concentrated the research team of high-energy accelerators in a section of Zhongguancun and established the High Energy Preparatory Office. At that time, it was proposed to build a 3.2 GeV proton synchrotron, which was later increased to 6 GeV. Fang Shouxian participated in the physical design and site selection of this accelerator. In August 1969, He Zuoxiu and others proposed a plan for the production of nuclear fuel with accelerators ("Project 698"), which can not only serve the needs of national defense, but also reserve technology and talents for high-energy physical development. Fang Shouxian proposed the use of a relatively mature superconducting proton linear accelerator to produce nuclear fuel, which was later condensed into the eight-character policy of "strong current, superconductivity, proton, straight line". But both of these plans were devastated by the storm of the Cultural Revolution.
In February 1973, the Institute of High Energy Physics was established on the basis of the Atomic Energy Institute, and a new journey of building a high-energy accelerator began. In March 1975, the state approved the construction plan of the prefabricated research base for high-energy accelerators ("Project 753") to carry out design research on high-energy accelerators. Fang Shouxian led the accelerator theory group to conduct in-depth research and completed the physical design of the 40 GeV proton synchrotron. However, under the situation of the "Cultural Revolution", the "753 Project" came to a standstill.
After the end of the "Cultural Revolution", the vast number of scientific and technological personnel rejoiced, but they were anxious to achieve results, and in November 1977, a "Great Leap Forward" plan was proposed: by the end of 1987, a high-energy physics experimental base comparable to that of CERN would be built, a 30 GeV strong flow proton ring accelerator would be built at the end of 1982, and a 400 GeV proton synchrotron ("Project 87") would be built in 1987. At the end of 1980, under the policy of tightening capital construction and adjusting the national economy, the "87 Project" was launched.
Fang Shouxian participated in the demonstration and theoretical design of the above 7 accelerator schemes, including electrons and proton accelerators, straight lines, cyclotrons, and ring accelerators. He grew up in the tempering, accumulated, expanded, and enriched the knowledge of accelerator physics in practice, and his desire to build a new high-energy accelerator for the motherland became stronger and stronger.
Fang Shouxian made a mobilization speech before the installation of the first acceleration tube
In April 1983, the State Council approved the report of the State Planning Commission on the construction plan of the positron-negative electron collider (BEPC), and the project was officially approved. At that time, Fang Shouxian was working on the design of the strong current antiproton storage ring at cernion research center (CERN), and when he heard the news, he immediately decided to return to participate in the construction of BEPC. After returning to China, Fang Shouxian was appointed as the deputy manager of BEPC engineering, responsible for the physical design of the accelerator and assisted Manager Xie Jialin.
According to the development process of international high-energy accelerators, it is first to build a stationary target accelerator, and then to build a collider. At that time, some people pointed out that China had not even done a stationary target accelerator, and that it was necessary to build a collider in one step, which was equivalent to "one step to the top", and the risk was too great. Fang Shouxian carefully analyzed the advantages and disadvantages of our country, believed that it was fully capable of overcoming scientific and technological difficulties, and encouraged the engineering team to work tenaciously and cooperate in the construction of the collider to achieve "one step to the top" in the field of high-energy accelerators.
The magnetic focusing structure is the basis for the design of the storage ring. The ring collider needs to have as small an envelope function as possible at the point of the positive and negative electron collision and achromatic dispersion throughout the collision segment. In large colliders, the mode of "arc standard period - achromatic node - final focus insertion node" is usually used, but the scale of BEPC is small, and if this scheme is adopted, the circumference of the ring is bound to be increased. Based on the quasi-periodic concept and achromatic method proposed by Fang Shouxian when he participated in the design of the antiproton storage ring at CERN, fang shouxian proposed to adopt the "matrix-final focus insertion node" scheme in BEPC. What he calls "matrix" means that the position of the focusing magnet remains cyclical, and the strength can be adjusted, which not only maintains the symmetry of the system, but also increases the flexibility of the structure. He led the physics team to carry out the optimization calculation of the specific scheme and creatively completed the design of the BEPC magnetic focusing structure.
At that time, the treatment of scientific research engineers participating in the construction of BEPC was very low, and the average monthly salary was only more than 100 yuan. Fang Shouxian often said that when the state is so tight on funds, it has spent 240 million yuan to build the collider, and we must carry forward the spirit of hard work, be diligent and thrifty, and make more contributions. In the construction of the project, he led by example and selfless dedication, working day and night with everyone, often living in the office, so that as soon as the situation occurred on the construction site, he could rush to the scene immediately. He led the team to establish an engineering quality assurance system, strictly control the quality, require relevant designers to be stationed in the factory, carry forward the "three old and four strict" style, strictly supervise all aspects from processing to assembly, and find problems on the spot and solve them at the scene. He also asked the key components and subsystems to carry out continuous trial operation of the whole machine as much as possible in practice before entering the tunnel to test its main indicators and stability.
Through the efforts of all the scientific research and engineering personnel, on October 16, 1988, BEPC realized the positive and negative electron collision, marking the successful completion of the collider. After the completion of BEPC, it quickly reached the indicator, its brightness exceeded 4 times that of similar accelerators in the United States, becoming the collider that occupied the international leading position in the performance of the τ-Cantonese energy zone, Fang Shouxian said excitedly: "My dream of a high-energy accelerator has finally come true."
<h1 class="pgc-h-decimal" data-index="02" > to redouble our efforts to carefully plan the future development of the collider</h1>
From 1988 to 1992, Fang Shouxian was the director of the Institute of High Energy Physics of the Chinese Academy of Sciences. Under his leadership, BEPC successfully achieved collisions and gradually achieved stable operation. The Beijing spectrometer was put into operation to obtain the world's largest J/Ψ data set, and achieved major results in accurate measurement of τ lepton mass, which was highly praised by the international high-energy physics community. The Beijing synchrotron radiation device is open to users and has become the first synchrotron radiation user device in China, which has effectively promoted the development of synchrotron radiation applications in China. On May 9, 1991, the State Planning Commission officially approved the establishment of the Beijing National Laboratory for Positron-Positron Collider, with Fang Shouxian as its director. This is our first national laboratory.
After stepping down as director of the Institute of High Energy, Fang Shouxian served as the director of the Beijing Positron-Positron Collider National Laboratory for a long time. While vigorously promoting the openness and output of BEPC, he actively planned the development strategy of BEPC. Fang Shouxian often said, "When the accelerator is built, it is the beginning of performance improvement." In June 1993 he participated in The third workshop on the τ-charm factory in Marbella, Spain, to report on the progress and future developments of BEPC. At the 3rd working meeting of the τ-Canton Factory in July 1993, Fang Shouxian made a report entitled "The Next Step of BEPC", proposing that depending on the intensity of national investment, there are three possibilities: large, medium and small. According to the national conditions at that time, he advocated the use of the "medium" scheme, that is, in the original tunnel of BEPC, the relevant equipment was modified to increase its brightness by about 10 times, reaching 1032 cm-2·s-1. This saves investment and only costs about 500-800 million yuan. Although this scheme is not as competitive as the τ-cantonese plant physically, it can maintain a world leading position for a considerable period of time.
In the mid-to-late 1990s, the Institute engaged in extensive discussions on the future development of BEPC. In June 1998, the Chinese Academy of Sciences conducted an academician evaluation of the Institute of High Energy Physics. Academician Fang Shouxian has made important contributions to the evaluation work. The evaluation recommended the BEPCII regimen for future development of BEPC.
After in-depth research and discussion, the Institute of High Energy determined a plan for the transformation of BEPC, which was supported by the leaders of the Academy of Sciences and officially submitted to the State Planning Commission. On July 27, 2000, the 7th meeting of the National Leading Group for Science and Education agreed in principle to carry out a major transformation of BEPC.
The fruitful results achieved by BEPC have aroused great attention and fierce competition in the international high-energy physics community. At the end of 2000, cornell university's positron-negative electron collider CESR, which originally worked in the high-energy zone of 2×5.6 GeV, saw the rich physical "mineral deposit" in the cantonment energy zone, and decided to reduce the energy of the beam to the finite physical energy zone (called CESR-c) to compete with the high energy institute, and its design brightness was the same as the single-ring scheme of BEPC transformation. Since CESR is the originator and experienced in twist orbital schemes, they claim that as long as 14 superconducting torsion oscillators are installed, they can achieve it within 2 years, much earlier than BEPCII. At that time, high energy was under tremendous pressure. Some people are pessimistic, believing that the competition between high-energy institutes and CESRs will undoubtedly die. Fang Shouxian pointed out that CESR is designed to run at 10 GeV centroid energy, CESR-c uses a torsion oscillator to increase the beam emission to obtain high brightness in the 4 GeV energy zone, which is an unconventional design that no one has ever done before and may not be able to achieve. We must not give up. With KEK's experience in achieving large cross angles, we were able to implement a double-loop solution in an existing tunnel. In order to continue to maintain the advantages of international high-energy physics research, we proposed a double-ring transformation scheme, and the design collision brightness is 100 times higher than the original collider, which is 3-7 times that of CESR-c, which greatly improves the competitiveness. The programme was supported by the scientific community and approved by the state, and construction began in early 2004 as a major retrofit of the Beijing Electron-Positron Collider, known as BEPCII.
Fang Shouxian fully supported BEPCII's double-ring scheme, believing that installing two storage rings in the existing tunnel to achieve a large cross-angle multi-beam group collision, although it was very difficult, but it could be achieved through hard work. After the official establishment of BEPCII, Fang Shouxian served as a consultant and played an important role in program design, engineering management and regulation and operation.
BEPCII not only achieves large-flow strength, high-brightness collisions, but also maintains a balance between synchrotron radiation experiments, which poses great challenges to the design layout, equipment construction and tunnel installation of accelerators. In order to reduce the impact on synchrotron radiation, Fang Shouxian personally practiced and guided the young people in the physics group, and after nearly 1 month of hard work, he finally found a magnetic focusing solution with good performance. The scheme not only meets the requirements of high brightness, but also maintains the position of the original synchrotron radiation beam line station unchanged, saving engineering funds, accelerating the schedule, and laying the foundation for the success of BEPCII.
From BEPC to BEPCII, Fang Shouxian poured valuable energy and effort. At the 30th Anniversary Seminar of BEPC held on October 20, 2018, Mr. Fang Shouxian made a keynote speech entitled "Beijing Positron-Negative Electron Collider". At the end of his speech, he emotionally said the following four sentences: Recalling the past is worthy of our remembrance and pride; it is very difficult to maintain and develop a place; continuous innovation on the basis of BEPC, pushing China's high-energy physics, synchrotron radiation and accelerators to a new peak; and sincerely hoping that the younger generation will carry forward the spirit of BEPC's seeking truth from facts, selfless dedication, and tenacious struggle, and achieve more brilliant achievements in the years to come.
Fang Shouxian at the BEPC 30th Anniversary Seminar
<h1 class="pgc-h-decimal" data-index="03" > foresight to promote the development of synchrotron radiation light sources</h1>
The light source is the beacon of human civilization. Synchrotron radiation light source is an advanced light source that uses relativistic electrons to generate electromagnetic radiation when deflected in the magnetic field, which has the advantages of high brightness, wide spectrum, collimation and coherence, and is a weapon for scientific research. The development of synchrotron radiation light sources in the world has experienced the first generation of parasitic high-energy physical experiments, the second generation of synchrotron radiation, and the third generation of light sources with higher performance and mainly generated by plug-in magnet components. Beijing Synchrotron Radiation Device (BSRF) is the first generation of synchrotron radiation light source of BEPC's "one machine, two uses" and the first synchrotron radiation device in China.
After the completion of BEPC, it has realized the efficient operation of high-energy physical and synchrotron radiation, and there are also situations when the two have different requirements for beam performance and when both sides compete for the machine. Fang Shouxian keenly discovered this problem, and in the early days of BEPC operation, he proposed the construction of a dedicated synchrotron radiation light source, and instructed the graduate students to complete the physical design of a third-generation synchrotron radiation light source. In April 1992, Fang Shouxian, in his academic report to the Faculty of Mathematics and Sciences of the Chinese Academy of Sciences, further elaborated on the two opportunities for the vision of the Institute of High Energy, namely the construction of a high-brightness τ-japonica factory and a high-performance synchrotron radiation light source of 1.5 GeV.
In November 1993, ding dazhao, Fang Shouxian and Xian Dingchang proposed to build a third-generation synchrotron radiation light source with advanced performance and medium scale in China. In January 1994, when Fang Shouxian was invited to discuss with Director Yang Fujia the development direction of the Shanghai Institute of Nuclear Research of the Chinese Academy of Sciences (later the Shanghai Institute of Applied Physics), he described the content of this proposal, believing that the Shanghai Institute of Nuclear Power could participate in the competition and strive to build a light source in Shanghai. Director Yang immediately asked Fang Shouxian to give guidance and support on the participation of the Nuclear Institute in the competition, and Fang Shouxian gladly accepted. "One stone stirs up a thousand waves", Yang Fujia conveyed the plan to prepare for the construction of the light source to the whole institute, which was approved and responded to by the colleagues of the whole institute. In 1994, the Institute of Nuclear Nuclei submitted a "Report on proposals on the construction of a third-generation synchrotron radiation light source in shanghai" to the Chinese Academy of Sciences and the Shanghai Municipality, which received strong support from the municipal government and the leaders of the institute.
On January 7, 2004, the executive meeting of the State Council approved the project proposal of Shanghai Light Source. On December 25 of the same year, Shanghai Light Source broke ground in Zhangjiang Hi-Tech Park in Pudong. Through the efforts of all the project builders, Shanghai Guangyuan was first illuminated in December 2007, and was completed and opened to users in April 2009. As one of the most advanced third-generation synchrotron radiation light sources in the world, Shanghai Light Source has made a large number of important research achievements in the past 10 years of open operation. Fang Shouxian served as the director of the Shanghai Light Source Engineering Science and Technology Committee, and played a key role in the establishment, pre-research, construction and commissioning of the light source project.
<h1 class="pgc-h-decimal" data-index="04" > to move to the forefront of strong current proton accelerators</h1>
The strong current proton accelerator with beam energy of the magnitude of GeV can produce a large number of neutrons when bombarding metal targets, and has a wide range of applications in the fields of energy, environment and materials, and is an important frontier direction for the development of international particle accelerators. In the tortuous journey of "seven up and seven down", Fang Shouxian participated in the research of the strong current superconducting proton linear accelerator for the production of nuclear fuel, and also participated in the design of several proton synchrotrons, especially the "753" and "87" projects. While building the positron-negative electron collider and the synchrotron radiation light source, he personally practiced and impacted the forefront of the strong current proton accelerator.
In 1983, Professor Rubia, nobel laureate in physics, proposed a new concept of "energy amplifier", which attracted widespread attention internationally. The "energy amplification" here refers to the use of a beam of a strong current proton accelerator to bombard the spallation target in a reactor in a subcritical state using U238 or thorium fuel, generating a large number of exogenous neutrons, turning the reactor into a critical state, so that the chain fission reaction can be sustained, and the energy generated is much greater than the energy consumed by the accelerator, also known as the accelerator-driven subcritical system (ADS).
In Professor Rubia's scheme, a cyclotron is used to generate a strong current proton beam. Cyclotrons have the advantage of continuous beam operation, but to achieve the beam energy of the GeV level, the magnet system will be very large. Fang Shouxian recalled the "eight-character policy" of "strong current, superconductivity, proton, and straight line" of the "698 Project" that he participated in more than ten years ago, and proposed the ADS technology route based on the superconducting linear accelerator. In March 1996, he and Ding Dazhao and six other academicians proposed to the Department of Mathematics and Physics of the Chinese Academy of Sciences to "carry out research on clean nuclear energy systems that make full use of uranium resources as soon as possible", and organized a number of seminars to promote ADS research in China.
In 1999, the Ministry of Science and Technology approved the 973 project "Basic Research on Physics and Technology of Accelerator-Driven Clean Nuclear Energy Systems", and Fang Shouxian was appointed as a member of the project expert group. He led the team in the design and development of the key RF quadrupolar field accelerator (RFQ) in the strong current linear accelerator. According to the development of computer simulation technology, he proposed to skip the aluminum cold mold research stage and directly enter the technical route of the manufacture of oxygen-free copper prototypes, breaking the traditional international practice, saving money and accelerating the progress. After 5 years of struggle, Fang Shouxian led the project team to successfully develop China's first energy 3.5 MeV strong current RFQ accelerator in 2006, and its main indicators reached the international advanced level.
China's first energy 3.5 MeV strong current RFQ accelerator
Fang Shouxian keenly noted with a high sense of responsibility that with the rapid development of the nuclear power industry, the disposal of highly radioactive waste will become one of the key issues in the sustainable development of nuclear energy in China. In 2007, the ADS R&D project was again included in the "973 Program". In the project mission statement, he changed the focus of research from energy to nuclear waste transmutation, and changed the name of the project to "Research on Key Technologies for Accelerator-Driven Nuclear Waste Transmutation" and served as a consultant for the project. In 2008, Fang Shouxian was entrusted by the Department of Mathematics and Physics of the Chinese Academy of Sciences to organize 4 academician consultation meetings, invited 21 academicians and experts in the field of nuclear science and technology to analyze and evaluate the relationship and development prospects of China's fast neutron reactor and ADS, and formed such a consensus: fast reactor focuses on the proliferation of nuclear fuel, ADS focuses on the transmutation of nuclear waste, the two complement each other, and it is more reasonable to choose ADS in terms of nuclear waste transmutation. The opinions consulted by academicians were adopted by the leaders of the Chinese Academy of Sciences, and also provided a basis for the pilot project of "Future Advanced Nuclear Fission Energy - ADS Transmutation System" implemented by the Chinese Academy of Sciences in 2011.
Complementary to synchrotron radiation and reactor neutron sources, spallation neutron sources are also an important platform for discipline research, and have extensive and important applications in the frontier fields of science such as physics, chemistry, life, materials, medicine, national defense and energy, and are also an important frontier for the development of strong current proton accelerators, and only a few developed countries in the world have such devices. According to the needs of China's scientific and technological development and national strategy, Fang Shouxian, Ding Dazhao, Zhao Zhixiang, Chen Hesheng and other experts submitted a project proposal of "Multi-purpose Neutron Science Device - Pulsed Strong Neutron Source" to the Ministry of Science and Technology in August 2000.
In September 2000, President Lu Yongxiang of the Academy of Sciences issued a directive asking us to "organize a study on the necessity and feasibility of building a spallation neutron source in China." According to the instructions of the Dean, the Faculty of Mathematics and Sciences set up an advisory group led by Fang Shouxian and composed of 12 academicians to carry out consulting work on the research of spallation neutron sources, and held two consultation meetings in May and August 2001. In the consultation report completed in early November, it was agreed that the Institute of Physics of the Chinese Academy of Sciences proposed to build a medium-scale spallation neutron source (CSNS) with a beam power of 100 kW in the second phase of the knowledge innovation project. Subsequently, Fang Shouxian, Academician Zhang Zong and other scientists worked together to vigorously promote the directional project of the Academy of Sciences "Innovative Research on the Key Technology of Spallation Neutron Source on Multidisciplinary Platforms", organized and participated in the research of CSNS accelerator scheme design, the key technology of proton linear accelerator and the key technology of fast pulse synchrotron, laying the foundation for the establishment of CSNS.
In May 2006, the Guangdong Provincial Development and Reform Commission organized the leaders of the Institute of High Energy and the Institute of Physics to visit the three candidate sites of spallation neutron sources proposed by Guangdong Province. Fang Shouxian participated in this expedition and made important contributions to the decision-making of the spallation neutron source point in Dongguan.
After the CSNS project construction project was established, Fang Shouxian served as the director of the CSNS Engineering Science and Technology Committee, presided over the meetings of the previous science and technology committees of the project, organized experts in related fields in China, and provided suggestions for the design, construction and commissioning of CSNS. Fang Shouxian also makes full use of his extensive international contacts to strive for international cooperation channels for CSNS, introduce key technologies, solve technical difficulties, and cultivate professional talents. Fang Shouxian is very concerned about the design of the CSNS accelerator, puts forward many guidance on the design of key parts, and constantly optimizes the design, improves performance, and controls the cost. Although he is nearly eighty years old, he has visited the project construction site nearly 20 times and enthusiastically guided the work.
On October 20, 2011, CSNS laid the foundation stone in Dongguan City, Guangdong Province, and Fang Shouxian participated in the groundbreaking ceremony of the project construction. CSNS has encountered many difficulties and technical difficulties in the construction of the project, and Fang Shouxian has actively provided suggestions and suggestions to help everyone overcome difficulties. On August 27, 2017, the first target shot successfully obtained the expected neutron beam. After 6 and a half years of efforts, CSNS was built as planned, reached the acceptance target, passed the national acceptance on August 23, 2018, was put into formal operation, and was soon opened to users, making China the fourth country with a spallation neutron source after the United States, the United Kingdom and Japan. Fang Shouxian served as the director of the CSNS Project Science and Technology Committee and played an important role in all stages of CSNS construction.
Aerial view of The source of Chinese spallation neutrons in Dongguan City, Guangdong Province
<h1 class="pgc-h-decimal" data-index="05" > Lao Ji Futuo threw himself into the proton therapy accelerator battlefield</h1>
In October 2012, during the 9th General Assembly of the Accelerator Branch of the Chinese Physical Society, coinciding with Mr. Fang Shouxian's 80th birthday, the organizing committee arranged a special academic report unit. At the meeting, 5 experts respectively reported on the development of Beijing positron-negative electron collider, Shanghai light source, heavy ion accelerator, China spallation neutron source and ADS, and Fang Shouxian made a wonderful report entitled "Proton Precision Therapy and Accelerator".
Building a proton therapy accelerator is Fang Shouxian's dream for many years, which is related to the health of the people. While making significant contributions to the development of high-energy accelerators in China, Fang Shouxian has been thinking about how to put the cutting-edge technology of high-energy accelerators into the main battlefield of the national economy. He has said many times: "I have been an accelerator for a lifetime, and I have spent a lot of resources on the country, and now I should do something for the country." After in-depth research, Fang Shouxian learned that proton and heavy ion accelerators have become the most advanced tumor radiotherapy equipment in the world, which is an effective means to deal with cancer, while domestic research and development is still blank. Fang Shouxian actively promotes and leads the research of proton therapy accelerators. He believes that proton therapy equipment is a large scientific and engineering device with extremely high scientific and technological content and great investment, and the general enterprise is unable to develop it, if the state does not invest vigorously and develops independently, then China's market will be monopolized by foreign equipment. Proton therapy equipment is similar in technology to CSS, and it is a large scientific research project, which can just play the specialty of the high-energy institute. Since 2007, he has guided a number of graduate students and postdoctoral fellows in the design of proton therapy accelerators, conducted pre-research on key technologies, and completed the conceptual design. In 2013, with the support of the Shanghai Municipal Government, the domestic proton therapy demonstration device was officially launched, and the Shanghai Institute of Applied Physics, together with Ruijin Hospital affiliated to Shanghai Jiao Tong University and Epqiang Particle Equipment Co., Ltd., jointly developed it, with Fang Shouxian as the general consultant of the project.
In the program design stage, Fang Shouxian has organized a number of international and domestic seminars to optimize the design, after repeated comparisons, determined the synchronous accelerator slow introduction scheme, and according to the concept of precision treatment, personally claped the board using advanced scanning methods and high-precision rotation of the treatment head, so that the design reached the international advanced level. Different from the accelerator for scientific research, the medical accelerator is a kind of equipment with commercial value, which cannot get relevant information from the manufacturer, and all key technologies must rely on their own research and development. In the process of device and equipment development, Fang Shouxian went deep into the front line of technology, listened to the problems encountered by R & D personnel, proposed a path to solve difficulties and encouraged everyone to be brave in innovation, and solved a large number of key technical problems.
The rotating treatment head treats the patient at the optimal angle and is a complex system of beam focusing, scanning, measurement, positioning and dose measurement. This is also the equipment that Fang Shouxian has not dealt with in the previous accelerators, no factory in China has manufacturing experience, and only a few companies such as Hitachi in Japan, Mitsubishi and IBA in Belgium have similar products abroad. Rely on imports or do it yourself? In order to speed up the development of the entire device, at the beginning it was considered to purchase a set of rotary treatment heads, but after contacting foreign companies, it was not only expensive, but also the technology was not disclosed. Under such circumstances, Fang Shouxian actively promoted the self-development and production of relevant domestic manufacturers, personally participated in and guided the physical design of the rotating treatment head, adopted the advanced ± 180 degree program, overcame various technical difficulties, and finally successfully built China's first proton rotary treatment head.
Rotational treatment head of domestic proton therapy demonstration device
In 2018, the first domestic proton therapy demonstration device was completed and entered the commissioning stage, including proton accelerator, beam transport line and three treatment rooms of fixed, rotating and eye beam.
The old Ji Futuo is determined to be in a thousand miles; the martyr is in his twilight years and his heart is full of heart. In the nearly 10 years from the establishment of this proton therapy demonstration device to the construction, Fang Shouxian often traveled between Beijing and Shanghai, once he learned that the project encountered difficulties, he always rushed to the scene at the first time to understand the situation, personally guided the work, and proposed solutions to solve the problem. But who knows how much pressure he has endured and how many difficulties he has overcome. Fang Shouxian's wife has been ill for many years, not only can not help internally, but also needs to be taken care of by others, he often patronizes the domestic market, and is distressed by not being able to find a suitable nanny. On the eve of the Spring Festival in 2019, Fang Shouxian went to Shanghai to coordinate the technical problems of the project, but he fell ill shortly after completing the task and returned to Beijing, and never returned to the Proton Accelerator Cancer Treatment Center of Shanghai Ruijin Hospital to see the first domestic proton therapy device treat patients, leaving his beloved particle accelerator combat position forever.
Particle acceleration, the great sage of the country. Mr. Fang Shouxian has dedicated his life's energy to the cause of particle accelerators in the motherland, and his lofty spirit and outstanding life have inspired us to forge ahead and continue to strive for the realization of the Chinese dream of the great rejuvenation of the Chinese nation.