On April 10, 1957, it became known that the energy of the proton accelerator launched at the High Energy Laboratory of the Joint Institute for Nuclear Research (JINR) exceeded the energy of the most powerful American synchrophasotron at that time in the world and reached 8.3 billion electron volts (GeV).
The launch of the Soviet proton accelerator took place on March 15, but the general public only learned about it after the installation broke the world record.
At that time, there were three accelerators operating in the world: two in the USA and one in the UK.
They were significantly inferior to the new Soviet synchrophasotron.
“The highest particle energy that physicists have ever been able to artificially create has been achieved,” the Pravda newspaper reported on April 11.
Vladimir Iosifovich Veksler, Soviet experimental physicist, founder of accelerator technology in the USSR, creator of the JINR synchrophasotron, Academician of the USSR Academy of Sciences, laureate of the Lenin Prize
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© David Sholomovich
In the same issue, an article by Vladimir Veksler, Director of the JINR High Energy Physics Laboratory, Corresponding Member of the USSR Academy of Sciences, was published.
He spoke about the difficulties that scientists had to overcome to launch the accelerator, as well as about the principles of operation of the revolutionary installation.
The readers learned that the weight of the ring electromagnet of the synchrophasotron was 36 thousand tons, and the average diameter of the steel ring reached almost 60 m. The continuous operation of 56 powerful pumps made it possible to reduce the pressure in the vacuum chamber, inside which accelerated particles move, to a billionth of the atmosphere.
“The magnetic field, subjecting the particles to its continuous influence, is verified to within tenths of a percent.
An insignificant error, even the slightest distortion of this field, would be sufficient to disable the accelerator,” Veksler said in the article.
The physicist also spoke about how the elementary particle accelerator works.
“At some point, they (particles) are, as it were, “injected” into the vacuum chamber from a linear accelerator ... The magnetic field that controls the movement of particles slowly increases with time.
In this case, the period during which the protons make a complete revolution inside the vacuum chamber is also reduced.
In exact accordance with the change in the duration of one revolution of the protons, the frequency of the electric field that accelerates the particles also increases.
The mechanism by which particle acceleration is carried out is called autophasing,” summed up Vladimir Veksler, without mentioning that it was he who discovered and formulated this mechanism.
Relativistic barrier
Recall that the design that made it possible to accelerate particles in an electric field was invented in 1929 by the American scientist Ernest Lawrence.
The physicist suggested launching particles in a circular path so that they could be repeatedly exposed to electrodes in a magnetic field.
Such an accelerator was called a cyclotron; the first installation of this type was built by Lawrence and his colleagues in 1930-1931.
The scientist was awarded the Nobel Prize in Physics.
The USSR did not want to lag behind the USA in the research of the microworld.
In 1938, a group of Soviet scientists headed by academician Abram Ioffe turned to the country's leadership with a proposal to start research in the field of the structure of the atomic nucleus.
At that time, only one cyclotron was built in the USSR, but it was inoperable.
Synchrophasotron control panel.
Joint Institute for Nuclear Research (JINR), 1973
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© Boris Ushmaikin
The scientists' plans received state support, but physicists faced a serious technical challenge in their work.
It turned out that the particle energy in the accelerators designed by Lawrence cannot exceed 20 million volts (20 MeV) for protons.
As the energy of the particle increases, the synchronism (resonance) between its motion and the accelerating field decreases.
As a result, particle acceleration stops.
For electrons, this barrier is even lower, since they are able to accelerate faster to the threshold value.
It was possible to overcome this obstacle thanks to the discovery of Vladimir Veksler.
In 1944, a Soviet scientist proposed the idea that during resonant acceleration, the frequencies of particle circulation and the accelerating field must constantly coincide - remain synchronous.
Wexler proved that it is possible to increase the speed of moving particles by gradually increasing the strength of the magnetic field.
As it turned out, such an acceleration process not only makes it possible to multiply the energy of particles, but also is resistant to small failures - minor desynchronization is automatically eliminated.
Therefore, the principle discovered by Wexler was called "autophasing".
A year later, independently of Veksler, an American physicist Edwin Macmillan made a similar discovery, but he recognized the superiority of his Soviet colleague.
Both scientists subsequently were nominated for the Nobel Prize more than once.
Macmillan got it, but for work not related to autophasing.
"A milestone in development"
On May 2, 1949, the Council of Ministers of the USSR issued a resolution on the creation of a synchrophasotron for an energy of 7-10 GeV, Vladimir Veksler was appointed scientific and technical leader of the project.
Before proceeding with the construction of a large accelerator, physicists in a separate building on the territory of the P.N.
Lebedev of the USSR Academy of Sciences (FIAN) built a model of the synchrophasotron.
To launch the installation, a number of unforeseen technical problems had to be solved; the launch took place in 1953.
The JINR Large Accelerator was built by the end of 1956, and work began on its integrated launch in December.
On March 15, 1957, the launch of the mega-installation took place.
However, information about this was made public only after the energy of the Soviet synchrophasotron exceeded the indicator of the most powerful particle accelerator at that time, which operated in the American Berkeley.
The design energy of 10 GeV was reached by protons in the synchrophasotron on 16 April.
And the installation was put into operation a few months later.
The building of the Joint Institute for Nuclear Research in Dubna, 1977
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© Boris Ushmaikin
For three years, the Dubna Synchrophasotron held the world leadership in the energy of accelerated particles.
In 1970, the first beams of relativistic deuterons with an energy of 10 GeV were obtained at the synchrophasotron, and subsequently the nuclei of various chemical elements were also accelerated.
Over the years of work at the accelerator, some new elementary particles were discovered - for example, in 1960, the scientific world learned about the existence of an anti-sigma-minus-hyperon.
The operation of the synchrophasotron was stopped in 2002.
However, atomic research in Dubna continues: in 2022, it is planned to commission the NICA collider (Nuclotron based Ion Collider fAcility).
The construction of the accelerator began in 2013 at the Joint Institute for Nuclear Research.
The collider belongs to the megascience class projects and will allow physicists to recreate in the laboratory environment the processes and conditions that arose at the dawn of the existence of our Universe in order to shed light on its history.
Data is planned to be obtained by the collision of heavy ions.
The assembly of the facility started in December 2021, when the first superconducting magnet was installed in the accelerator tunnel.
As Grigory Shirkov, Assistant Director of JINR, Doctor of Science, Corresponding Member of the Russian Academy of Sciences, said in an interview with RT, elements of the legendary Soviet synchrophasotron found a new life in the NICA collider.
“Now the magnet of this accelerator is used as the basis for one of the elements of the “megascience” of the NICA project.
And although 65 years have passed since the launch of the synchrophasotron, it still serves modern science,” the scientist noted.
Moreover, the NICA collider itself was created in a tunnel that remained inside the 1957 accelerator after the coils were removed from it.
“So the scientific tradition continues.
At one time, the launch of the synchrophasotron became a very important event for the whole world.
Accelerator
worked for many years, and a lot of unique scientific data was obtained on it, it was a very important stage in the development of accelerator technology, ”summed up the scientist.