Vladimir I. Veksler( Soviet physicist, founder of synchrotron)
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Biography Vladimir I. Veksler
Vladimir Veksler was born in Ukraine in Zhytomyr March 3, 1907. His father died in World War.
In 1921, during the widespread famine and devastation, with great difficulty, without money, Vladimir Veksler gets into starvation prednepovskuyu Moscow. A teenager is in the house-commune, established in Khamovniki, in an old mansion, abandoned by owners.
Wexler is different from an interest in physics and electrical engineering practice, he has collected a crystal radio, which in those years was an unusually difficult task, read a lot, a good student at school.
After leaving the commune, Wexler retains many of its educated views and habits.
Note that the generation to which belonged to Vladimir I., an overwhelming majority with complete disregard to the household belonged to the parties of their lives, but fanatically fond of academic, professional and social problems.
Wexler, among other commune members graduated from the nine-year high school and together with all the graduates entered the workers on the production, where he worked as an electrician for more than two years.
His thirst for knowledge, love of books and rare intelligence were seen in the late 20-ies the young man received a "Komsomol" in the Institute.
When Vladimir I. finished institute, conducted another reorganization of higher education institutions and change their names. It turned out that Wexler did in the Plekhanov Institute of National Economy, and graduated from MEI (Moscow Power Engineering Institute) and was qualified as an engineer specializing rengenotehnika
. In the same year he joined the laboratory of X-ray analysis of the All-Union Electrotechnical Institute in Lefortovo, . where Vladimir I. began his work with the construction of measuring instruments and to explore methods of measuring ionizing radiation, . ie,
. flows of charged particles.
In this laboratory Wexler worked for 6 years, having risen rapidly from the laboratory to the head. There have already shown a characteristic "handwriting" Wexler as a talented scientist and experimenter. His disciple, Professor M. S. Rabinovich later wrote in his memoirs about Wexler: "Almost 20 years he collected, mounted various invented them installed, never churayas any work. This allowed him to see not only the facade, not only its ideological side, but all that is hidden behind the final results, the accuracy of measurements for the cupboards brilliant installations. All his life he studied and reshaped. Until the last years of life in the evenings, on vacation, he had carefully studied and outline the theoretical work ".
In September 1937, Wexler moved from the All-Union Electrotechnical Institute of Physics Institute of the Academy of Sciences named P. N. Lebedev (FIAN). This was an important event in the life of a scientist.
By this time, Vladimir I. has defended his thesis, whose theme was the use of the device and designed them "proportional amplifiers".
In FIAN Wexler began to study cosmic rays. Unlike A. I. Alikhanova and its employees, taken a liking to the picturesque mountain Aragats in Armenia, Veksler participated in scientific expeditions to Mount Elbrus, and then, later, the Pamirs - the roof of the world. Physicists around the world studied the streams of charged particles of high energy that can not be obtained in terrestrial laboratories. Researchers have raised closer to the mysterious flow of cosmic radiation.
Even now, cosmic rays have an important place in the arsenal of astrophysicists and specialists in high-energy physics, nominated exhilarating theory of their origin. At the same time to obtain a particle with such energy for the study was simply impossible, but for physicists it was simply necessary to study their interaction with other particles and fields. Already in the thirties, many atomic scientists thought arose: how nice it was to get such high particle "cosmic" energies in the laboratory with the help of reliable devices for the study of subatomic particles, . method of learning which was one - the bombing (as figuratively said before, and rarely speak now) of some other particles,
. Rutherford discovered the existence of atomic nuclei by bombarding atoms thick shells - alpha particles. The same method was used to open the nuclear reactions. To convert one chemical element into another, it was necessary to change the composition of the nucleus. This was achieved by bombardment of nuclei by alpha particles, and now - the particles dispersed in powerful accelerators.
After the invasion of Hitler's Germany, many physicists immediately joined in the work of military importance. Wexler interrupted the study of cosmic rays and began the construction and improvement of radio equipment for the needs of the front.
At this time, Physics Institute, Academy of Sciences, as well as some other academic institutions, was evacuated to Kazan. Only in 1944 was able to organize an expedition from Kazan to the Pamirs, where the group was able to continue Wexler launched in the Caucasus studies of cosmic rays and nuclear processes induced by high-energy particles. Without considering in detail the contribution of Wexler in the study of nuclear processes associated with cosmic rays, which were devoted many years of work, we can say that it was significant and gave many important results. But perhaps the most important thing is that the study of cosmic rays has led scientists to completely new ideas of particle acceleration. In the mountains Veksler had the idea to build particle accelerators to create your own "cosmic rays".
Since 1944,. I. Wexler moved to a new area, which has taken center stage in his scientific work. Since then, the name of Wexler forever linked with the creation of large 'self-focusing' accelerators and the development of new methods of accelerating.
However, he has not lost interest in cosmic rays and continued to work in this area. Wexler was involved in the high scientific expeditions to the Pamirs and during the 1946-1947 period. In cosmic rays show a fantastically high-energy particles inaccessible to accelerators. Veksler was clear that the 'natural accelerator' particles to such high energies can not be compared with the 'creation of human hands'.
Wexler suggested a way out of this impasse in 1944. New principle that operated boosters Wechsler, the author called self-focusing
. By this time, was established accelerator of charged particles such as "Cyclotron" (Wexler in a popular newspaper article as the principle of the cyclotron, said: "In this device, a charged particle, . moving in a magnetic field spiral, . continuously accelerating alternating electric field,
. This can indicate to the cyclotron energy of the particles in the 10-20 million electron-volts). But it became clear that the threshold of 20 MeV by this method does not move.
In the cyclotron magnetic field varies cyclically, dispersing the charged particles. But in the process of acceleration is the increment of the mass of particles (as it should be under the TSA - the special theory of relativity). This leads to disruption of the process - after a certain number of revolutions of the magnetic field begins to slow down instead of accelerating particles.
Wexler proposes to start slowly increase over time the magnetic field in a cyclotron, feeding magnet ac. Then it turns out that the average frequency of particles on a circle will be automatically maintained equal to the frequency of the electric field applied to the dees (a pair of magnetic systems, distorting the path of the particle and magnetic field)
. With each passing through the slit the particles have dees and receive an additional increment of different mass (and correspondingly, . receive different increment of radius, . which turns their magnetic field), depending on the voltage field between the dees at the time of acceleration of the particle,
. Of all the particle can be distinguished equilibrium ( "lucky") particles. For these particles the mechanism automatically maintains a constant period of treatment, especially simple.
"Lucky" particle during each passage through the slit dees have an increment of weight and increasing the radius of the circle. It is exactly offset by reductions in radius, due to the increment of the magnetic field during one revolution. Consequently, the "lucky" (equilibrium) particle can be resonantly accelerated up until the increase of the magnetic field is.
It turned out that the same ability and have almost all other particles, only the acceleration lasts longer. In the process of acceleration of all the particles will experience vibrations about the equilibrium orbit radius of particles. The energy of the particles on the average will be equal to the energy of the equilibrium particle. Thus, practically all the particles involved in the resonant acceleration
. If instead of slowly increasing over time the magnetic field in the accelerator (cyclotron), feeding the magnet with alternating current, to increase the period of the alternating electric field applied to the dees, even then switch to 'self-focusing'
Next Wexler wrote:
"It would seem that for the appearance of self-focusing and accelerating the implementation of resonant necessarily change over time or magnetic field, or during electrical. In fact, it is not so. Perhaps the simplest idea (but not simple for practical implementation) the method of acceleration, set by the author before other methods can be implemented at a constant in time magnetic field and constant frequency ".
In 1955, when Wexler wrote his pamphlet on the accelerator, this principle, as pointed out by the author, formed the basis of the accelerator - microtron - accelerator, which requires powerful sources of microwave. According to Wexler, microtron "not yet received distribution (1955). However, several electron accelerators at energies up to 4 MeV has been working for several years ".
Wexler was a brilliant popularizer of physics, but, unfortunately, because of employment is rarely performed with the popular articles.
The principle of self-focusing has shown that we can have a stable region of the phases and, consequently, can change the frequency of the accelerating field, not fearing to leave the field of resonant acceleration. It is only necessary to choose the phase of acceleration. By changing the frequency of the field it became possible to easily compensate for the change in mass of particles. Moreover, the frequency change can be a quick spiral of the cyclotron closer to the circle and accelerate particles up until enough magnetic field to keep the particles in a given orbit.
Described synchroscope, which changes the frequency of the electromagnetic field, called synchrocyclotron or Phasotron.
In synchrotron uses a combination of two principles of self-focusing. The first of these is the basis Phasotron, which has already been said - is the change in frequency of the electromagnetic field. The second principle is used in synchrotrons - here is changing the magnetic field.
Since the discovery of phase stability, scientists and engineers began to design accelerators to billions of electron volts. The first of them in our country was proton accelerator - synchrophasotron 10 billion electron-volts in Dubna.
Design of large accelerator began in 1949 on the initiative in. I. Wexler and C. I. Vavilov, start-up took place in 1957. The second large accelerator built in Protvino near Serpukhov already at 70 GeV energy. It works now, not only Soviet scientists, but physicists in other countries.
But long before the launch of two giant "billions" of accelerators in the Physical Institute of the Academy of Sciences (FIAN) under the leadership Wexler were built accelerators of relativistic particles. In 1947, the launch took place on the accelerator of electrons to energies of 30 MeV, which served as a model of a larger electron accelerator - synchrotron energy 250 MeV. The synchrotron was launched in 1949. These accelerators researchers Physics Institute, USSR Academy of Sciences carried out first-rate work on meson physics and atomic nucleus.
After starting Dubna synchrotron, a period of rapid progress in the construction of accelerators for high energy. In the USSR and other countries have been built and put into action many of the boosters. These include the already mentioned accelerator to 70 GeV at Serpukhov, 50 GeV in Batavia (USA), 35 GeV in Geneva (Switzerland), 35 GeV in California (USA). Currently, physicists set themselves the task of creating an accelerator for a few tera-electron volts (tera-electron volts - 1012 eV).
In 1944, when he was born the term "autophasing". Veksler was 37 years old. Wexler was a gifted organizer of scientific work and the head of the scientific school.
Method of self-focusing as a ripe fruit waiting for a visionary scientist who takes it and gets hold of them. A year later, regardless of the principle of self-focusing Wexler opened the famous American scientist poppy-Milan. He acknowledged the priority of the Soviet scientist. Mac-Milan have repeatedly met with Veksler. They were very friendly, and the friendship of two remarkable scientists is never darkened until his death Wexler.
Accelerators, built in recent years, although based on the principle of self-focusing Wexler, but, of course, significantly improved compared with first-generation machine.
In addition to self-focusing, Wexler suggested other ideas for accelerating particles, which have been very fruitful. Development of these ideas Wexler extensively involved in the Soviet Union and other countries.
In March 1958 the House of Scientists on Kropotkin Street held the traditional annual meeting of the Academy of Sciences. Wexler described the idea of a new principle of acceleration, called them "coherent". It allows you to accelerate not only the individual particles but clusters of plasma, consisting of a large number of particles. "Coherent" method to accelerate as gently spoken Wexler in 1958, allows you to think about the possibility of accelerating particles to energies of a thousand billion electron-volts and even higher.
In 1962, Wexler led a delegation of scientists flew to Geneva to attend the International Conference on High Energy Physics. Among the forty members of the Soviet delegation had such big physics as a. I. Alikhanov, H. N. Bogolyubov, D. I. Blokhintsev AND. YA. Pomeranchuk, M. A. Markov. Many scientists who have served in the delegation were accelerator specialists and students Wexler.
Vladimir Veksler for several years was chairman of the Commission on High-Energy Physics International Union of Pure and Applied Physics.
October 25, 1963 Veksler and his American counterpart - Director of Radiation Laboratory, University of California behalf of Lawrence Edwin McMillan - was awarded the Prize of the American "Atoms for Peace '.
Wexler was the permanent director of the Laboratory of High Energies, Joint Institute for Nuclear Research in Dubna. Now, about your stay in this city Wexler recalls nazvannnaya his name street.
In Dubna years focused research work the Wexler. He combined his work at the Joint Institute for Nuclear Research work at the Physical Institute named P. N. Lebedeva, where a distant youth began his journey researcher, was a professor at Moscow State University, where he headed the department.
In 1963, Wexler was elected an academician-secretary of the Office of Nuclear Physics, Academy of Sciences of the USSR and permanent occupied this important post.
Scientific advances in. I. Wexler were highly appreciated by being awarded the State Prize of the First Degree and the Lenin Prize (1959). Outstanding scientific, educational, organizational and social activities of scientists has been awarded three Orders of Lenin, the Order of Labor Red Banner and medals of the USSR.
Vladimir Veksler died Sept. 20, 1966 from a second heart attack. He was only 59 years old. In life he always seemed younger than his years, was an energetic, active and tireless.