Guide
On October 1, 2021, Mr. Yang Zhenning will celebrate the 100th birthday of the lunar calendar, and the academic community has launched activities or anthologies to congratulate Mr. Yang on his 100th birthday. Since August, Mr. Sai has published a series of classic articles that relive Mr. Yang Zhenning's important contributions. Since September 22, it has jointly launched a series of articles with "Intellectuals" on "Yang Zhenning in a Hundred Years of Style". Invite Zhu Bangfen, Pan Jianwei, Shi Yigong, Rao Yi and other scientists and Mr. Yang Zhenning's students to send blessings for Mr. Yang's 100th birthday.
In this issue, Mr. Yang Zhenning's student Wei Jie wrote a special article recalling his experience under Mr. Yang and Yang Zhenning's foresight in the field of accelerator physics research.
Written by | Wei Jie
Mr. Yang Zhenning is a master of physics and my teacher. Here, I would like to talk about Mr. Yang's foresight in the field of accelerators and his enlightenment and help to the younger generations of students.
In September 1984, I left the Theoretical Physics Group of the Department of Engineering Physics of Tsinghua University and went to the Department of Physics of the State University of New York at Stony Brook, where Mr. Yang is located, to pursue a Doctorate degree, preparing to focus on condensed matter theoretical physics. Mr. Yang was the director of the Institute of Theoretical Physics and taught in the Department of Physics.
Figure 1: Annual photo of the Department of Physics and Astronomy, State University of New York at Stony Brook, 1986. （Department of Physics and Astronomy, State University of New York at Stony Brook）
In the first year, I took the PHY515 course on quantum mechanics taught by Mr. Yang. Mr. Yang uses L.I. Shiff's quantum mechanics textbook "Quantum Mechanics", which is very popular with graduate students. The first time I left homework, I left two questions that were quite difficult for me. I consulted Zhang Shousheng, who was one year older than me, and for the first time, I felt that doing theoretical physics might not be my strong point.
A year later, I passed the PhD qualification in the Department of Physics and began to conduct research on condensed matter theoretical physics under the guidance of my supervisor. After a year of hard work, I felt that the progress was slow, and I came to Mr. Yang's office in confusion to ask for advice. Mr. Yang pointed out: High-energy theoretical physics needs experimental verification, and the high-energy state required for experimental verification depends on particle accelerators. Under the existing acceleration principle and technical means, the construction of ultra-high energy accelerators is expensive, so the future of high-energy physics lies in new accelerator physics theories and methods.
Mr. Yang cited successful examples of his teachings from theoretical physics to accelerator physics, such as Zhao Wu, who led the physical design of the Super Superconducting Collider (SSC), and Lihua Yu, who was the original free electron laser (FEL) theorist, and so on.
After Mr. Yang's two clicks, I decided to change my research direction and focus on accelerator physics. Mr. Yang contacted Ernest D. Courant, a pioneer in the field of accelerators, and recommended me to study with E D. Courant at Brookhaven National Laboratory (BNL), 30 kilometres from Stony Brook, and Mr. Yang became my PhD supervisor at Stony Brook.
At the time, Brookhaven National Laboratory was conducting pre-work on the Relativistic Heavy Ion Collider (RHIC) accelerator project. At the end of 1989, I defended my dissertation at Stony Brook on a RHIC research topic entitled Longitudinal Dynamics of the Non-adiabatic Regime at Transition Crossing.[1] After the defense, Mr. Yang was very happy and modestly said, "I learned something."
Figure 2: Group photo with members of the defense committee after Wei Jie's doctoral dissertation defense meeting in 1989. From left to right: S.Y. Lee, J. Kirz, C.N. Yang (Committee Chair), E.D. Courant, J. Wei.
Looking back on my five years at Stony Brook, Mr. Yang guided me to learn and experience how to realize my own value, do what I am best at, and develop in the field of accelerators. Mr. Yang is both a respectable master of physics and a mentor to many of his juniors, and many of his classmates in Stony Brook have benefited from Mr. Yang's teachings (Figure 3). Every time he asks for advice from his husband, he will listen carefully, the questions asked are always very sharp, and he can always give unique insights, which is suddenly enlightening.
Of course, Mr. Yang's transcendent wisdom and quick thinking always make me feel difficult to look back on. Mr. Yang gave the "Symmetry" lecture, which the students still enjoy to this day. Every year around the Spring Festival, the Chinese Students and Scholars Association in Stony Brook holds a celebration, and Mr. Yang is invited to come. Mr. Yang's office on the top floor of the sixth floor of the Stony Brook Math Building often comes to my memory, and Mr. Yang's teachings have benefited me for a lifetime.
Figure 3: In 1997, the 2nd Global Chinese Society of Physics and Astronomy (OCPA) conference was held at the Yuanshan Hotel in Taipei. During the conference, Mr. Yang invited several Stony Brook alumni who were guided by him into the accelerator field to have a dinner at the Hyatt Hotel: Zhao Wu (fourth from left), Li Shiyuan (first from left), Yu Lihua (sixth from left), Wei Jie (third from left), etc.
Since entering the accelerator field in 1986, I have had the opportunity to participate in the pre-research, design and construction of several cutting-edge large-scale projects in the accelerator field. During my Ph.D., I practiced transition crossing, a traditional topic in the field of accelerators, and discovered that RHIC, as the world's first synchronous accelerator ring composed of superconducting magnets that requires crossing critical energy, requires a slow increase in field strength due to the need for superconducting magnetic fields, and longitudinal nonlinear effects can cause serious beam dispersion and loss near critical energy. After discovering the major engineering design defects related to this, improvement measures such as reducing the beam through energy dispersion and critical energy jump by reducing the RF voltage were proposed and adopted. I successfully obtained my PhD and contributed to the construction of the project.
Ten years after graduation, I continued to do accelerator physics research, engineering physics design, and construction in RHIC Engineering (Figure 4). The proposed solution to the beam loss and divergence problem caused by intrabeam scattering using a stochastic cooling mechanism was successfully implemented on the RHIC device about two decades later.
Figure 4: Aerial view of the Relativistic Heavy Ion Collider (RHIC) accelerator built at Brookhaven National Laboratory.[2] （Brookhaven National Laboratory）
Since then, I have been responsible for the accelerator physics work of Brookhaven National Laboratory's participation in the US part of the Large Hadron Collider (US-LHC) of the European Organization for Nuclear Research (CERN), proposing the principle and specific scheme of beam dynamic correction for magnetic field errors in the collision area.
From 1999 to 2005, I was involved in the Spallation Neutron Source (SNS) project built at Oak Ridge National Laboratory (ORNL) by six U.S. Department of Energy National Laboratories (ORNL), initially responsible for the physics, physical design and pre-study of engineering accelerators, and later overall responsible for the design and construction of SNS storage rings and transportation systems. Until the project is successfully completed [3].
During this time, with Mr. Yang as one of the referees, I went from being an assistant researcher to a tenured researcher at Brookhaven National Laboratory and a Fellow of the American Physical Society in 2003.
Fig. 5: Schematic diagram of the design concept of the Spallation Neutron Source (SNS) project built at Oak Ridge National Laboratory [3]. The project was built in collaboration with six U.S. Department of Energy-affiliated national laboratories. （Oak Ridge National Laboratory）
For the past seven decades, the design of high-energy physics accelerators has been based on the 1952 E.D. The principle of strong focusing of accelerators discovered by Courant et al. [4]. As the energy of accelerated particles continues to rise, the construction of high-energy physics accelerators tends to be more and more lengthy, the construction team is large, and the construction cost is high.
The study of more advanced acceleration principles has not yet matured enough to be applied to specific projects. For these reasons, Mr. Yang has been more committed to supporting the development of medium and low energy and application accelerators over the years, including accelerator projects serving light sources, neutron sources, and ion therapy in the fields of energy, biology, materials, and medical treatment.
From 2005 to 2009, with the direct support and encouragement of Mr. Yang and the help of Mr. Fang Runhua of Hong Kong, I came to the Institute of High Energy Physics of the Chinese Academy of Sciences to participate in the design and pre-research of the China Spallation Neutron Source (CSNS) (Figure 6), and served as the manager of the China Spallation Neutron Source Project (preparation), responsible for the preparatory work of the project.[5]
The strong current accelerator-based project, which is led by the Institute of High Energy Physics of the Chinese Academy of Sciences, was fully completed in 2018 and has now reached the design target and is open for operation, becoming China's first pulse spallation neutron source, serving many cutting-edge research fields.
Figure 6: Schematic schematic of the conceptual design of China Spallation Neutron Source (CSNS) in Dongguan in 2007 [5]. (Institute of High Energy Physics, Chinese Academy of Sciences)
In 2009, with the support of Mr. Yang, I was invited by Tang Chuanxiang and President Gu Binglin to teach in the Department of Engineering Physics of Tsinghua University to prepare for the preparation of a Compact Pulsed Hadron Source (CPHS) based on a proton beam (Figure 7). The technology promoted by this project is not only applicable to low and medium energy proton acceleration and neutron scattering, imaging platforms, but also extends to proton application platforms, ion therapy, nuclear physics research and application platforms, and accelerator-driven subcritical devices (Figure 8).
The Hadron Accelerator Project complements Tsinghua's traditional technology based on electron accelerators and light sources and irradiation technologies, forming an accelerator research and development platform suitable for the development of the university. At that time, Guan Xiaoling, Long Zhenqiang and other teachers joined Tsinghua and formed a proton accelerator and neutron technology team. With the enthusiastic encouragement of Mr. Yang who lives in Tsinghua, the full support of President Gu Binglin, and the all-round cooperation of Tang Chuanxiang, Chen Huaibi and other department leaders, the project design and pre-research developed rapidly, and the main campus of Tsinghua was quickly selected and built[6].
After I left Tsinghua in 2010, Mr. Wang Xuewu took over the project development, and soon the accelerator project was completed and entered the user operation. In recent years, the Tsinghua Proton Accelerator team has undertaken the design and construction of a space irradiation simulation facility based on the Proton Synchrotron, and has recently successfully commissioned and operated.
Figure 7: Schematic design of the 2010 Concept Design of the Compact Pulsed Hadron Source (CPHS) built on the main campus of Tsinghua University.[6] (Tsinghua University)
Figure 8: The development direction of accelerators based on the development concept of compact pulsed hadron source technology of Tsinghua University in 2010 includes neutron application platforms (neutron scattering, neutron imaging, boron neutron medical treatment, etc.), proton application platforms (hadron irradiation, imaging, etc.), hadron medical treatment, nuclear physics research and application platforms (isotope acquisition, rare isotope research) and accelerator-driven subcritical applications (nuclear transmutation waste treatment, thorium-based nuclear reaction energy).
In 2010, I was invited to Michigan State University to work at the university and served as the project leader for the Facility for Rare Isotope Beams (FRIB) accelerator, responsible for the design, pre-research, construction, commissioning, and operation of the accelerator (Figure 9).
The construction of this accelerator project, which is cooperated by the U.S. Department of Energy and Michigan State University, with a total investment of about one billion US dollars, was approved in 2010, passed the project benchmark in 2012, and started construction in 2014.
The world's largest heavy ion linear accelerator uses 2K liquid helium superconducting radio frequency cavity acceleration, liquid metal film electron peeling, and rotating target and rotating waste beam station technology, and will serve the research and application of the most advanced indicators in the field of nuclear physics [7].
Figure 9: Schematic diagram of the engineering design of the Facility for Rare Isotope Beams (FRIB) facility built on the main campus of Michigan State University [7]. （Michigan State University）
It has been 35 years since he was introduced to the accelerator field by Mr. Yang in 1986. For me personally, the rewards of the accelerator industry are so unique that physical ideas can be turned into reality through the execution of engineering projects. Throughout the construction process, experience endless gains in terms of physics, technology, teamwork, and friendship building. Being able to experience the whole process from concept to substance makes me feel incredibly honored and enjoy it.
I was fortunate to have Mr. Yang's timely guidance when my career started in confusion, and found a career that I was good at and loved (Figure 10) [9]. We sincerely thank Mr. Yang for his teaching, guidance and support for more than 30 years, and sincerely wish Mr. Yang a childlike heart, a new crane hair, and a long and healthy life!
Photo 10: Wei Jie met with Mr. Yang in Sha Tin, Hong Kong in 2017.