Abram Isaakovich Alikhanov (ahl-eek-ahn-off;[1] Russian: Абрам Исаакович Алиханов, né Alikhanian; 4 March [O.S.

20 February] 1904 – 8 December 1970) was a Soviet experimental physicist[2] of Armenian origin who specialized in particle and nuclear physics.

His brother, Artem Alikhanian, was based in Soviet Armenia and led the Yerevan Physics Institute for many years.

[7] His father, Isahak Alikhanian (d. 1925),[5] was a railroad engineer (train driver) in the Transcaucasus Railway, while his mother, Yulia Artemevna (née Sulkhanova), was a housewife.

[5][6][2] Abram Ioffe appointed Alikhanov head of the positron laboratory at the Department of Solid-State Physics at the Physical-Technical Institute.

According to Viktor Frenkel, their work became a "starting point for the application of radio engineering to experimental nuclear physics in the Soviet Union.

"[3] Abov wrote that in 1933–34 Alikhanov and his colleagues were the "first to study in detail the spectrum of positrons from external pair conversion over the entire energy range.

"[6] He added, "those investigations made it possible to reveal gamma lines that had previously been unknown, whereby it was possible to reconstruct the diagrams of decays of excited nuclei.

"[6] They went on to study beta decay using not the usual Wilson cloud chamber, but a spectrometer developed by Alikhanov and Mikhail Kozodayev.

[3] It was a "radically improved" version of the "classical magnetic spectrometer with transverse field, fitting it with a system of coincidence-coupled gas-discharge counters.

[9] Alikhanov "discovered that positrons were present even in the absence of a converter made from a heavy element, and this led him to the discovery of a new phenomenon—production of an electron-positron pair as a result of internal conversion of the energy of the excited nucleus."

Alikhanov's group also studied scattering of fast electrons in matter and beta spectra of radioactive substances.

"[3] Alikhanov and his group, including his brother Artem Alikhanian, also erroneously concluded in the existence of cosmic radiation particles, called by them varitrons, which supposedly possessed a broad spectrum of masses.

"[11] Luis Walter Alvarez noted that the brothers received the Lenin Prize for their unverifiable discoveries and "for them to have retracted their claims would have been embarrassing to their government.

[5] Between 1947 and 1951 Alikhanov headed the Department of Structure of Matter at the Faculty of Physics and Technology of Moscow State University.

The Scientific-Technical Council was headed by Boris Vannikov and included Alikhanov (initially as it scientific secretary), Igor Kurchatov, Pyotr Kapitsa, Abram Ioffe and others.

[2] The laboratory/institute initially focused on what Alikhanov had already begun working on: construction of a nuclear reactor based on heavy water.

[2] In 1959 Alikhanov led the design of 10 MW experimental research heavy-water reactors, which were built in China and Yugoslavia under his supervision.

[2] Alikhanov led several studies and investigations based on the new instrument,[6] most notably research on "pion scattering on nucleons with large momentum transfer.

[6][30] Mikhail Shifman noted that Alikhanov was the "driving force behind the decision to build the first strong focusing accelerators" in the Soviet Union: at ITEP and at the Institute for High Energy Physics (IHEP) in Protvino, near Serpukhov.

[31] Abov noted that the decision by the Ministry of Defense was an "irreparable blow" for Alikhanov, because it "deprived the institute of any prospects for further development.

[5] A group of his colleagues and students wrote that he was "extremely straightforward and generous in his dealings with people, irrespective of whether the matter was a scientific or a merely personal problem,"[2] while David Holloway described him as "hot-tempered.

He frequented Artsimovich's apartment to tell stories about his friends the satirist Mikhail Zoshchenko, the poet Anna Akhmatova, and the composer Dmitri Shostakovich.

[40] Alikhanov later signed a collective letter addressed to the Soviet leaders asking them to return Kapitsa to the head of the Institute for Physical Problems.

[42] He did not collaborate with the authorities during the antisemitic anti-cosmopolitan and the Doctors' plot campaigns in the post-war years when Jews were fired from their workplaces.

[44][45] In 1956 Alikhanov came under pressure when several members of the ITEP staff gave pro-democracy speeches at the institute's Communist Party organization.

"[46] Yuri Orlov, one of the dissidents who was forced to leave ITEP, found work at the Yerevan Physics Institute, headed by Alikhanov's brother, Artem.

"[47] In March 1966 he joined Pyotr Kapitsa, Andrei Sakharov and others calling on Leonid Brezhnev not to rehabilitate Stalin.

[48] "For all of the many facets of his scientific career, Alikhanov was primarily an experimental physicist—an experimentor in the highest sense of the word, as exemplified by Faraday and Rutherford."

"[52] Yuri Orlov suggested that Alikhanov "was not such a genius as Landau or Kapitsa", but argued that he was "a distinguished scientist and honest man", who transmitted to his students "his awesomely high standards.