ALIKHANOV, ABRAM ISAAKOVICH

(b. Elisavetpol [now Kirovohad, Azerbaijan S.S.R.], Russia, 4 March 1904; d. Moscow, U.S.S.R., 8 December 1970)

physics.

Alikhanov’s father, Isaak Abramovich Alikhanian, was a railway engineer; his mother, Iulia Artemevna. was a housewife. There were four children: two sons (the younger, Artem Alikhanian, became a well-known physicist) and two daughters. In 1912 the familv moved to Aleksandropol (now Leninakan, Armenian S.S.R), where Alikhanov began his studies at a commercial school. He graduated from another commercial school, in Tiflis (now Tbilisi, Georgian S.S.R.), in 1921 and the same year enrolled in the Georgian Polytechnical Institute. After a few months, however, he moved to Petrograd (now Leningrad), where he continued his studies at the Faculty of Physics and Mechanics of the Petrograd Polytechnical Institute, from which he graduated in 1930. It was at that time that he russified his name from Alikhanian to Alikhanov.

In 1927 Alikhanov started to work at the Physical-Technical Institute. Combining studies at the Polytechnical Institute with scientific research at the Physical-Technical Institute was common practice among the best students of the faculty.

Alikhanov’s first research work at the Physical-Technical Institute, devoted to X-ray physics, was carried out in Petr Ivanovich Lukirskii’s laboratory under Lukirskii’s supervision, Alikhanov x-rayed aluminum in the temperature range of 550–600°C and proved that in this range aluminum retains its structure and there is no allotropic transformation. This result contradicted the data obtained by others. Subsequently, X rays became not a tool but the subject of Alikhanov’s research. The most important of these investigations was a study of the total internal reflection of X rays from thin layers and the estimation of the depth of their penetration into the medium. Alikhanov also proved that the laws of classical optics can be applied to the reflection of hard X rays. This research formed the basis for the monograph published in 1933.

Research on nuclear physics began at the Physical-Technical Institute in late 1932. In 1934 Alikhanov was appointed head of the laboratory for positron physics. The work of his group was devoted to the investigation of pair production and of the resultant positron spectrum, especially the latter’s dependence on the γ radiation released and on the atomic number of the irradiated material. For observation of positrons, Alikhanov, his brother, and his student M. S. Kozdaev used an original combination of a magnetic spectrometer and two contiguous Geiger-Müller counters making coincidence counts. This work became a starting point for the application of radio engineering to experimental nuclear physics in the Soviet Union. Another series of investigations by Alikhanov and collaborators was concerned with the β-decay of artificially radioactive nucleides. This work used not a Wilson cloud chamber but the Alikhanov-Kozodaev spectrometer, which enabled the authors to obtain more precise data concerning the form and bounds of the β-spectrum and its dependence on the atomic number of the source of radiation. The scattering and slowing of relalivistic electrons (those with velocities comparable with the velocities of photons, keeping in mind use of the relativistic corrections) in matter were investigated as well.

Two more of Alikhanov’s prewar investigations must be mentioned. A method of determining the rest mass of the neutrino, using decay of the nuclei of Be7, was suggested in his laboratory in 1938. A secondary nucleus of Li⁷ gains momentum from the neutrino created as a result of capture of an orbital electron by the nucleus of Be⁷. The discrete energy spectrum of the neutrino and, as a consequence, of the nucleus facilitates the experimental solution of the difficult problem of determining the rest mass of the neutrino. The information about the experiments planned at Alikhanov’s laboratory under his leadership appeared in the Soviet physical literature in 1940 but the work was not carried out because of the war. In 1942 the experiment was carried out by James Allen.

Another aspect of Alikhanov’s work (which he began in the late 1930’s) was associated with cosmic rays. By the summer of 1941 an expedition to the Pamir Mountains under his leadership had been prepared, but the project was not realized because of the war. In 1942, however, as well as later, observations of cosmic rays were carried out during an expedition to the Armenian Mountains. The experiments demonstrated the presence of a stream of fast protons in cosmic radiation, but also included a serious mistake. The conclusion that there exist in cosmic radiation particles (called by Alikhanov and his group “varitrons”) possessing a broad spectrum of masses was erroneous. Alikhanov was sharply criticized because the possibility of the existence of particles with a broad mass spectrum was perceived as nonrealistic at that time. Its reality was determined later, through a quite different type of experiment.

At the end of 1942 Alikhanov joined the research on uranium, He became the head of investigations, conducted in a special laboratory, of a heavy-water technique in reactor engineering, and in 1945 he established a research center for these investigations, the Heat Engineering Laboratory (now the Institute of The oretical and Experimental Physics) at Moscow. He served as its director almost until the end of his life. In 1949 the first heavy-water reactor went into operation at the institute. Before the war Alikhanov (with Igor Vasilevich Kurchalov) had participated in the design and construction of the first cyclotrons in the Soviet Union and Europe (at Kur chatov’s laboratory in 1944). In 1952 he returned to this work, and in 1961 a proton accelerator with strong focusing and an energy of 7 GeV was completed at the institute. Alikhanov and his collaborators also participated in the design of a 70 GeV accelerator at Serpukhov. During the last years of his life he worked in high-energy physics and the physics of mesons, having been stimulated by the discovery of nonconservation of parity in weak interactions.

Alikhanov was married twice. He and his first wife, A. Prokofieva. had a son, Ruben, who became a physicist. They were divorced about 1942, Alikhanov’s second wife, Slava Roshal’ was a violinist. Their son. Tigran, and their daughter, Evgenia. both became musicians.

Painting also played a great role in Alikhanov’s life. His friend the Armenian artist Martiros Sergeevich Sarian once painted a portrait of him.

Alikhanov’s work was highly recognized: in 1939 he was elected corresponding member, and in 1943 full member, of the Soviet Academy of Sciences. He was three times awarded the Stale Prize, and in 1954 he became a Hero of Socialist Labor.

During the last two years of his life, Alikhanov suffered from the effects of a cerebral hemorrhage. Nevertheless, he did not retire. In 1968, however, he resigned his directorship, and from then on, he limited his work to scientific research in his laboratory at the institute.

BIBLIOGRAPHY

I. Original Works, “Polnoe vnutrennee otrazhenie rentgenovykh luchei ot tonkikh sloev” (The total internal reflection of X rays from thin layers). in Zhurnal eksperimentalnoi i teoreticheskoi fiziki, 3 no. 2 (1933), 115. written with Lev A. Artsimovich: Optika rentgenovskikh luchei (X-ray optics: Leningrad and Moscow, 1933): “A New Type of Artificial β-Radioactivity,” in Nature, 133 (1934), 871–872, written with Artem I. Alikhanian and B. S. Dzhelepov: “Emission of positrons from a Thorium-Active Deposit,” ibid., 136 (1935), 475–576, written with Artem I. Alikhanian and M. S. Kozodaev: “Zukon sokhraneniia impulsa pri annigiliatsii positronov” (The conservation of momentum law in positron annihilation), in Doklady Akademii nank SSSR. 1 , no. 7 (1936). 275, written with Artem I. Alikhanian and Lev A. Artsimovich; “Obrazovanie par pod deistviem γ-lucheii” (Pair creation under y-ray influence), in Izestiia Akademii nauk SSSR. seriia fizicheskaia. (1938). no, 1/2, 33: “Forma β-spektra RaE vblizi verkhnei granitsy i massa neitrino” (The spectrum mode of RaE near the upper hound and the mass of the neutrino), in Doklady Akademii nauk SSSR, 19 , no. 5 (1983), 375 “O poteriakh energii bystrymi elektronami pri prokhozhdenii cherez veshchesto” (On energy losses of fast electrons during passage through matter), ibid., 25 , no. 3 (1939), 193. written with Artem I. Alikhanian; “Novii dannii o prirode kosmicheskikh lunchei” (New data on the nature of cosmic rays) in Uspekhi fizicheskikh nauk, 27 , no. 1 (1945), 22. written with Artem I. Alikhanian: “Tiazhelovodnyi energeticheskii reaktor s gazovym okhlazhdeniem” (The heavy-water energy reactor with gas cooling), in Atomnaia energiia, 1 (1956), 5, written with V. V. Vladimirskii, P. A. Petrov. and P. I. Khristenko: Slabye vzaimodeistviia: Noveishie issledovaniia β-raspada (Moscow, 1960), trans, by william E. Jones as Recent Research on Beta-Disintegration (New York, 1963): “Dalneishie poiski (μ → e + y)-raspada” (Further searches of (Omu; → e + y), in Zhurnal experimentalnoi i teoreticheskoi fiziki, 42 (1962), 630–631. written with coauthors:Izbrannye trudy (Selected works). S. I. Nikitin et al., eds, (Moscow, 1975).

II.Secondaty Literature. A. P. Aleksandreov, B. V. Dzelepov. S. I. Nikitin and I. B. Kharition, “Pamiati Abrama Isaakovicha Alikhanova” (in memory of A. I. Alikhanov). in Uspekhi fizicheskikh nauk, 112 no. 3 (1974), 725–727: B. G. Gasparin. A. P. Grinberg, and V. J. Frenkel. A. I. Alikhanov v Fiziko-tekhnicheskon institute (A. I. Alikhanov in the physical-Technical Institute:Leningrad, 1986): A. P. Grinberg, “Gipoteza neitrino i novie podtverzhdaiushchii ee dannie” (Neutrino hypothesis and the new data that confirm it), in Uspekhi fizicheskikh nauk, 26 , no. 2 (1944). 189: and “Positive Electrons from Lead Ejected by y-Rays.” in Nature, 133 (1934), 581.

V. J. Frenkel