# Wang Ganchang

Wang Ganchang
Wang Ganchang
Born May 28, 1907
Changshu, Jiangsu, China
Died December 10, 1998 (aged 91)
Beijing, China
Residence China
Germany
USSR
Nationality China
Fields Physicist
Institutions
Nuclear industry Science and Technology Commission
China Association for Science and Technology
Chinese Physical Society
China Nuclear Society
NPC Standing Committee
Alma mater Qinghua University
University of Berlin
Doctoral advisor Lise Meitner
Known for anti-sigma minus hyperon
Influenced Frederick Reines
Notable awards JINR Prize (1961)
National Natural Science Award (1982)
National Science and Technology Progress Award (1985)
Two Bombs and One Satellite Meritorious Award (1999)

Wang Ganchang (Chinese: 王淦昌; pinyin: Wáng Gànchāng; Wade–Giles: Wang Kan-ch'ang) (May 28, 1907 – December 10, 1998) was a nuclear physicist from China. He was one of the initiators of research in China in nuclear physics, cosmic rays and particle physics. Wang figured among the top leaders, pioneers and scientists of the Chinese nuclear deterrent program. He was a member of the Chinese Academy of Science and a member of the Chinese Communist party.

In 1930, Wang first proposed to use a cloud chamber to study a new type of high-energy rays induced by the bombardment of beryllium with α particles, experiment conducted one year later by the English physicist James Chadwick, thus discovering a new type of particle, the neutron, and allowing him to win the 1935 Nobel Prize in Physics.

Wang first proposed the use of beta-capture to detect the neutrino in 1941.[1] James Allen employed his suggestion and found the evidence of existing neutrino in 1942. Frederick Reines and Clyde Cowan detected the neutrino via inverse beta-decay reaction in 1956 winning forty years later the 1995 Nobel Prize in Physics.

Wang also led a group to discover the anti-sigma minus hyperon particle at Joint Institute for Nuclear Research, Dubna, Russia in 1959.[2]

After May 1950, he became researcher and vice-director of the Institute of Modern Physics (中国科学院近代物理研究所). He was vice-director of the Soviet Joint Institute for Nuclear Research. From spring 1969, he was vice-director of the Ninth Research Institute (二机部第九研究院), predecessor of the China Academy of Engineering Physics. He was director of the China Institute of Atomic Energy (二机部副部长兼原子能研究所). He was deputy director of the Nuclear industry Science and Technology Commission (核工业部科技委). He was second vice-chairman of the China Association for Science and Technology. He was vice-chairman of the Chinese Physical Society (中国物理学会). He was first chairman of the China Nuclear Society (中国核学会). He was a member of the 3rd through 16th NPC Standing Committees.

In 2000, the Chinese Physical Society established five prizes in recognition of five pioneers of modern physics in China. The Wang Ganchang Prize is awarded to physicists in particle physics and inertial confinement fusion.

## Early years

Wang Ganchang was born in Changshu City, Jiangsu Province (江苏省常熟县支塘镇枫塘湾), on May 28, 1907.[3] In 1924, he graduated from the Shanghai Pudong High School (上海浦东中学). He then studied English for six months and car driving and repair for six months. He passed the entrance examinations for Qinghua University in August 1928.

He graduated from the Physics Department of Qinghua University in June 1929. He then became assistant professor of Qinghua University from 1929 to 1930. In his thesis "On the daily change of radon gas" (《清华园周围氡气的强度及每天的变化》), he was the first in China to published on atmospheric research and radioactive experiments.[4]

## Overseas student in Germany

In 1930 he went to study at the University of Berlin in Germany. As soon as he arrived in Berlin, hearing the Bothe report (博特报告) relating the emission of a new type of high-energy neutral radiation which was non-ionizing but even more penetrating than the hardest gamma rays derived from radium, induced by the bombardment of beryllium with α particles from a radioactive polonium source, therefore wrongly presumed to be gamma rays, Wang first suggested the use of a cloud chamber to study it. Lacking the support of his supervisor Lise Meitner, the experiment was nonetheless conducted one year later by the English physicist James Chadwick, thus discovering a new type of particle, the neutron, allowing him to win the 1935 Nobel Prize in Physics.

Four years later in 1934, Wang Ganchang received his Ph.D. with a thesis on β decay spectrum (German: Über die β-Spektren von ThB+C+C; Chinese:《ThB+C+C的β能谱》) under the supervision of Meitner before returning to China in April of that year.[5]

He first joined the Shandong University as a physics professor from 1934 to 1936 before becoming professor at the Zhejiang University and serving as head of the Department of Physics from October 1936 to 1950.

## The WW II years

Following the invasion of China by Japan in July 1937, Professor Wang Ganchang was forced to retreat with all the faculty of the Zhejiang University where he was a professor, to the primitive western mountainous hinterland of China.

Enduring difficult conditions, he nonetheless tried in 1939 to find on photographic films tracks of nuclear fission caused by neutron bombardment of cadmium acid.

In 1941, he first proposed an experiment to prove the existence of the neutrino by capturing K-electrons in nuclear reactions. Unfortunately, he was unable to implement the experiment because of the war. Fifteen years later Frederick Reines and Clyde Cowan employed his suggestion and detected the neutrino in 1956 winning forty years later the 1995 Nobel Prize in Physics. (In fact, the suggested technique of Prof Wang is only remotely related to the Reines, Cowan neutrino experiment. Reactor neutrinos and the inverse beta reaction were used, not a radioactive substance and K-Capture.)

## Founding of the P.R. China

From April 1950 to 1956 he was a researcher at the CAS Institute of Modern Physics and served as deputy director from 1952. There, at the invitation of Qian Sanqiang of the Institute of Modern Physics, he started studies of cosmic-rays with a circular 12 feet cloud chamber. In 1952, he designed a magnetic cloud chamber.

Professor Wang was the first to propose to establish China's first cosmic ray laboratory. Therefore, he directed the Luoxue Mountain Cosmic Rays Research Center (落雪山宇宙线实验站) in the Yunnan province high mountainous regions at 3185 meters above sea level from 1953 to 1956.

His study of cosmic-rays lead him to publish his findings on neutral-meson decay in 1955. By 1957 he had collected more than 700 recordings of new types of particles.

## The USSR years

In order to develop high energy physics in China, the Chinese government began from 1956 to send some experts to the Joint Institute for Nuclear Research at Dubna in the USSR to do field work and carry out the preliminary design of particle accelerators. The agreement on the establishment of JINR was signed on March 26, 1956 in Moscow, Wang Ganchang being one of the founders.[6]

On April 4, 1956, he went to the USSR to participate in planning the long-range development of peaceful utilization of atomic energy. Then many students were sent to the former Soviet Union to learn the technologies of how to build accelerators and detectors. Thus, the experimental group led by Professor Wang Ganchang analysing more than 40,000 photographs which recorded tens of thousands of nuclear interactions taken in the propane bubble chamber produced by the 10 GeV synchrophasotron used to bombard a target forming high energy mesons, was the first to discover the anti-sigma minus hyperon particles (反西格马负超子) on March 9, 1959:[7]

$\pi^- + C\to \bar\Sigma^- + K^0 + \bar K^0 + K^- + p^+ + \pi^+ + \pi^- + nucleus~~~recoil$

The discovery of this new unstable antiparticle which decays in (1.18±0.07)·10−10 s into an antineutron and a negative pion was announced in September of that year:[5]

$\bar\Sigma^-\to \bar n^0 + \pi^-$

No one doubted at the time that this particle was elementary, but a few years later, this hyperon, the proton, the neutron, the pion and other hadrons had lost their status of elementary particles as they turned out to be complex particles too consisting of quarks and antiquarks.

He served as deputy director from 1958 and worked there until 1960.

## Nuclear deterrent

On December 24, 1960 as he returned from the USSR, he accept to participate in the atomic bomb program, giving up research on elementary particles for the next 17 years. Within one year, he conducted more than 1000 detonation experiments at the foot of the Great Wall, in the Yanshan Mountain (河北省怀来县燕山), Huailai county, Hebei province.

In 1963 he moved to the Qinghai Plateau at more than 3000 meters, to continue polymerization detonation experiments. He then proceeded to Xinjiang's scorching Taklimakan desert to make preparation for the first nuclear test. Finally on October 16, 1964 the first atomic bomb test was conducted successfully. Looking at the rising mushroom cloud, rewarding four years of endeavours, he couldn't help shedding tears of excitement. Less than three years later, on June 17, 1967 the first hydrogen bomb test was conducted with success, shocking the world as China mastered this technology even before the French, and breaking the nuclear monopoly of the two superpowers.

In spring 1969, he served as vice-director of the Ninth Research Institute (二机部第九研究院) receiving the task of conducting the first underground nuclear test. Due to severe high altitude hypoxia, he had to carry an oxygen mask at work. After months of endeavours, the first underground test was successfully conducted on September 23, 1969. He also led the second and third Chinese underground nuclear tests.

## Fusion and nuclear energy

Wang Ganchang is the founder of Chinese laser fusion technology. In 1964 the Shanghai Optical Machinery Institute (上海光机所) developed a high-power 10 MW output laser. In late December of the same year, he proposed to the State Council using high-power laser beam targeting to achieve inertial confinement fusion, idea also independently developed at the same time by his Soviet counterpart Nikolai Gennadievich Basov. Unfortunately, due to political turmoil causing seven years of delay, his leading position in this field was lost.

By the end of 1978, his inertial confinement fusion research group established by the Atomic Energy began the construction of high-current accelerator. As an advocate of nuclear energy, he made with four nuclear experts in October 1978 the proposition to develop China's nuclear power. In 1980, Wang Ganchang promoted the plan of building 20 nuclear power plants including Qinshan, Zhejiang Province, Daya Bay, Guangzhou and Chinshan.

## Project 863

With outstanding achievements, he was also a leader in the fields of detonation physics experiments, anti electromagnetic pulse technologies, nuclear explosion detection, anti nuclear radiations technologies, laser stimulated nuclear explosion technologies.

On March 3, 1986, Wang Ganchang, Wang Daheng, Yang Jiachi and Chen Fangyun first proposed in a letter (《关于跟踪世界战略性高科技发展的建议》) to the Chinese government to launch researches covering lasers, microwaves, and electromagnetic pulse weapons. The plan would be adopted in November of that year under the code name Project 863 (“863计划”).[8]

## Awards

He received the first prize of the National Natural Science Award (国家自然科学奖) in 1982. He received the first prize of the National Science and Technology Progress Award (国家科技进步奖特等奖) in 1985. He received along with Qian Sanqiang both posthumously in September 1999 the special prize of Two Bombs and One Satellite Meritorious Award (“两弹一星功勋奖章”) granted by the State Council, the Central Committee of the Communist Party and Central Military Commission .

## Selected literature by Wang Ganchang

German (as K. C. Wang)
English (as K. C. Wang)
English (as G. Wang)
• Wang, N.; ——. "An 80-GW relativistic electron beam accelerator". Proceedings of the fifth International Conference on High-Power Particle Beams, USA, 1983.
• Wang, N.; ——. "100 Joule level KrF laser pumped by intense electron beam". Proceedings of the 2nd International Workshop on KrF Laser Technology, Alberta, Canada, 1990.
Chinese (as 王淦昌)
• ——．中性介子（π0）的发现及它的性质．物理通报，1951,1(12):34.
• ——，郑仁圻，吕敏．在铅板里发生的电子光子簇射．物理学报，1955,11(5):421.
• ——，肖健，郑仁圻，吕敏．一个中性重介子的衰变．物理学报，1955,11(6):493.
• 郑仁圻，吕敏，肖健，——．在云室中观察到一个Ｋ介子的产生及其核俘获．物理学报，1956,12(4):376．
• ——，吕敏，郑仁圻．一个长寿命的带电超子．科学记录（新辑），1957,1(2):21.
• ——，王祝翔，维克斯勒，维辽索夫，乌兰拉，丁大钊等．8.3 GeV/c 的负π介子所产生的Σ超子．物理学报，1960,16(7):365； ЖэТФ，1960,38:1356．
• ——，王祝翔，维克斯列尔，符拉娜，丁大钊等．在动量为 6.8±6亿电子伏/c的π介子与质子相互作用下A0（Σ0）及K0的产生．物理学报，1961,17(2):61； ЖэТФ，1961,40:464.
• ——，王祝翔．能量在10GeV以下的π-N，p-N和p-N相互作用．物理学报，1961,17:520.
• 丁大钊，王祝翔，——．奇异粒子的强相互作用．物理学报，1962,18:334.
• ——．利用高功率激光驱动核聚变反应．（内部报告）1964.
• ——．国际上惯性约束核聚变情况简介和对我国在这方面工作的意见．（惯性约束核聚变讨论会文集）1982.9.
• ——，诸旭辉，王乃彦，谢京刚，李鹰山，周昌淮，王璞．６焦耳ＫｒＦ激光的产生．核科学与工程，1985,5(1):1.
• ——，诸旭辉，王乃彦，谢京刚，李鹰山，周昌淮，王璞．１２．５焦耳电子束泵浦ＫｒＦ激光器．应用激光，1986,6(2):49.
• ——．王淦昌论文选集．北京：科学出版社，1987．
• 徐宜志，——．闪光－１强流脉冲电子束加速器．原子核物理，1987,9(2):69.
Russian (as Ван Ган-чан )
• ——; et al. (1960). "Исследование упругого pacceяния π мезонов с импульсом 6.8 GeV/c на протонах с помошью пропановой пузырьковой камеpы". ЖЭТФ 38: 426.
• ——; et al. (1960). "Рождение антипротонов при взаимодействии π мезонов с нуклонами". ЖЭТФ 38: 1010.
• Бирзер, H. г.; ——; Ван, Цу-чен; et al. (1961). "Неупругие взаимодействия π мезонов с импульсом 6.8 GeV/c с нуклонами". ЖЭТФ 41 (5): 1461.