Their names are in the history of the Institute

Remembering Lev Borisovich

9 November marks the 100th anniversary of the birth of Doctor of Physical and Mathematical Sciences Professor Lev Borisovich Pikelner. Since 1959, he worked at the Laboratory of Neutron Physics, headed the Department of Nuclear Physics and set the area of a number of investigations. His most striking achievement was the discovery of the parity violation effect in neutron resonances that is several orders of magnitude greater than the effect in the interaction of nucleons. For these investigations, Lev Borisovich was awarded I.M.Frank Prize "For outstanding achievements in Neutron Physics" in 1993. Olga Tarantina wrote down the recollections of three generations of laboratory employees - his colleagues and students.

V.I.Furman: When I recall Lev Borisovich, I mean two hypostases - one purely personal, human and the other - scientific, because we cooperated for many years as colleagues and then as friends. I began working in the Department of Nuclear Physics of FLNP as a theorist in 1961 under the supervision of FLNP Deputy Director Fedor Shapiro and until 1990, I had relatively little contact with Lev Borisovich in science, until he became Head of the Department in 1973, after the death of Fedor Shapiro. He was an experimenter and besides, he was 14 years older than me.

As head of a large department, he was characterized by extraordinary precision, self-discipline towards himself and others and at the same time, very correct self-discipline, extraordinary conscientiousness and self-criticism. He considered it necessary to carefully discuss his and others' results with colleagues, could not accept anything unwrought, was thoroughly accurate and precise, both in implementing experiments and in formulating final results. As for personal relationships, he was an open person, friendly, absolutely on an equal footing with us, younger comrades and with senior colleagues, Ilya Frank and Fedor Shapiro, as well as with his peers from the Laboratory Directorate.

The thing is that he came to our Laboratory in 1959 as an absolutely mature researcher, a candidate of technical sciences from the military institute near Zagorsk, where he came after having graduated from Moscow State University. There he completely independently carried out rather complex and dangerous experiments. They consisted of simulating the situation after an atomic explosion, studying how it would affect people, military equipment, electronics. For this, a very primitive system was used: there was a liquid, highly active source of gamma radiation based on a cobalt isotope that was positioned behind powerful protection on the ground and for the experiment was lifted into the air on an aerostatic balloon. It is clear that an aerostatic balloon is a poorly controlled thing and Lev Borisovich said that he had (and this is amazing!) special communications with the nearest air regiment: when he began an aerial experiment, fighters took to the air and he had the right to demand that the fighters open fire on the aerostatic balloon if it "broke loose" from its tether and carried this chemically and radiation-hazardous cup of cobalt to nearby populated areas.

At FLNP, he earned a well-deserved reputation rather fast that was not only due to his age, but also to his scientific qualifications, personal charm and ability to organize people. He never pressured anyone, never shouted, but was able to clearly track who was doing what. He learned it from the atmosphere that Fedor Lvovich had created in the Laboratory - always controlling who was doing what and unobtrusively but firmly ensuring that work on each topic was not delayed. Lev Borisovich immediately accepted this tactic, in general, he and Fedor Lvovich were on good, close terms and Lev Borisovich accepted Fedor Lvovich's ability to organize people very well, it was his style. Therefore, the working, creative atmosphere in the Department of Nuclear Physics that before Lev Borisovich was headed by the younger Vladislav Lushchikov, our Slava, was absolutely wonderful and very stimulating from the very beginning - they were ready to help you at any time, but you had to do the job yourself. This trait allowed Lev Borisovich to successfully head the Department for many years - from 1973 to 1990.

L.B.Pikelner's group (second from left) at the facility for experiments with polarized nuclei, 1973.

When he realized that he was approaching his age and perestroika had begun in the country, which I took an active part in, he began to gradually prepare me, a theoretician, although closely cooperating with the Department's experimenters to replace him. I did not want this position, I resisted, but Lev Borisovich, seeing some ability in me for this, gently but persistently pressed.

About a year and a half before he left his post, he had began to actively involve me in the activities that he himself was engaged in. Here is a striking example. In the late 1980s - early 1990s, the Hungarian physicist Dezso Kis that worked at FLNP when he was young, was elected Director of JINR and he began to impose "European" order here: the synchrocyclotron, the synchrophasotron are obsolete facilities, they should be closed, he said the same about IBR-30. But we understood that IBR-30 had just reached the maximum of its capabilities, its infrastructure took a long time to develop, it was complex and unique, there was no similar one in other places - first of all, we were talking about polarized resonance neutrons. It was imperative to carry out precision experiments using them, given that IBR-30 was the brightest source of pulsed neutrons in Europe in terms of luminosity.

The cycle of experiments carried out before the expiration of D.Kish's term of office together with PNPI (Gatchina) and IPPE (Obninsk) on studying P-even and P-odd angular correlations of fission fragments became one of the pinnacles of everything carried out on IBR-30 during its operation. Moreover, no one in the world has been able to repeat these experiments to this day. And Lev Borisovich played a very large role in organizing and carrying out this work and he involved me in writing all sorts of justifications for why IBR-30 should not be shut down. And IBR-30 was shut down only in 2001 after the expiration of its plutonium core resource.

During the years of D.Kish's directorship, it became fashionable to elect heads. In 1990, all employees of our department voted and to my surprise, I took the first place and Lev Borisovich - the second. I say it to show how he was able to foresee the situation and carefully implement his policy. Even if you did not want to, he knew how to gently, with jokes, but clearly and consistently set you on the "true path."

Everything was always in its place in his office. You would come to him with a question, he would answer - it is described in such a publication, he would stretch out his hand and take a magazine from his bookcase behind his back or from a card index. There was not a very large library in the office, nothing superfluous - the most necessary books, all the preprints, the necessary articles. People would turn to him for literature and he had a card index - he would write it down so that they would not forget to return it and afterwards, reminded them. He was such an organized person. It was very pleasant and useful to discuss science issues with Lev Borisovich, he always found time for it. He understood perfectly well that it was the most important stage of both the beginning of the work and overcoming the difficulties of its current implementation and comprehension, as well as summing up and writing an article. For several years, I worked quite closely with him on experiments to study the properties of delayed fission neutrons at the IBR-2 reactor. We wrote articles together and I saw how meticulously he approached every word and graph and so I looked into his creative laboratory. We sometimes argued and he, unlike some that always stubbornly stood their ground, could be convinced that one version of the presentation should be used and not another.

He was a bit unlucky, perhaps because of his meticulousness. In the 1970s, such an amazing phenomenon in the fission of excited nuclei as the levels of the second deformation well was discovered. Lev Borisovich's group members came close to their discovery, but they were just a little short of the energy resolution of the IBR-30 reactor and they carried out further experiments. And literally in the same year, German physicists published a paper with this discovery.

On the other hand, various groups that Lev Borisovich headed and inspired, carried out such precision work that no one else in FLNP or in the world had done. We are talking about measuring magnetic moments and deformation of excited states of nuclei after the capture of resonance neutrons. Only intense neutron fluxes of the IBR-30 pulsed reactor made it possible to see and to study the properties of excited states with an energy of 7-8 MeV and the distances between these excitation levels could be from 1 eV to 10-20 eV. Only pulsed neutron sources could provide such a unique energy resolution. Lev Borisovich was actively involved in this neutron spectrometry of compound states. Under his supervision, brilliant experiments were carried out to search for parity non-conservation effects and other polarization effects in neutron resonances that no one has been able to repeat to this day and 25 years have passed. Such experiments are very complex, they require polarized neutrons of a fairly wide energy range and high intensity.

He was a very good teacher, he could explain complex tasks very simply, omitting unnecessary details. I did not hear his lectures, but I know how he wrote articles, spoke at seminars and at our Neutron Schools in Alushta. He was a born teacher, but he was not very active in teaching. The problem was with the students of the MIREA branch themselves that did not really wish to study. He was more focused on his own scientific work and if necessary, on administrative work, the head of the department should help to provide employees with devices and materials in close cooperation with the deputy directors.

Lev Borisovich, as Head of the Department, had variable working groups. He had postgraduate students from Bulgaria, the GDR, Poland, Russia, Czechoslovakia, or rather young employees that later defended candidate theses in joint work with him. I think that during the time that he was Head of the Department, 8-10 young employees defended candidate theses under his supervision. He got the title of professor precisely for these students.

In his youth and middle years, he played volleyball and tennis. I did neither, yet I was an active mountain climber. But Lev Borisovich ran with his friend, a well-known person in Dubna, David Bell and here, we sometimes crossed paths. They were both already old, over 60, they ran slowly, to maintain their athletic form. At that time, his knees did not hurt yet, this was a consequence of volleyball loads and when they began to hurt, Lev Borisovich maintained his passion for tennis until a very old age. And my younger friends told me how they played with him: Lev Borisovich was standing, almost without moving and they were running along the back line of the court from corner to corner, all in a sweat. That's how he chased the young and won! In addition, he loved traveling. Together with his wives, with Yu.P.Popov, V.A.Karnaukhov and V.P.Shirikov, he went on kayaking and hiking trips for about 15 years. Lev Borisovich, being a little older than the others, was always the life of the party, as Yura Popov and Nelly Shirikova said. Lev Borisovich was a very authoritative sports fan at the Institute, he was a member of the JINR Sports Council for many years.

It is hard to imagine that our friend and senior colleague, an outstanding physicist and a very worthy person is turning 100. He did not live to see this difficult to achieve date, but he is in our memory as a living and close interlocutor, a real senior comrade!

V.R.Skoy: I came to the Laboratory in 1986 and Ilya Frank immediately sent me to the group of Lev Borisovich. At that time, the investigation of parity nonconservation in nuclear interactions with polarized neutrons was underway. I joined these investigations. Lev Borisovich was the permanent scientific leader of this research. We had a facility for polarizing neutrons POLYANA with a complex system of cryostats, microwave circuits for pumping and other equipment. Viktor Alfimenkov was engaged in technical issues of ensuring the operation of the facility and Lev Borisovich directed the activities to study the effect of parity nonconservation on various nuclei - lanthanum, tin, cadmium, bromine. At first, they tried to assign me to help V.P.Alfimenkov, but he did not know how to teach, he preferred to do everything himself. Gradually, I turned to processing of the measurement results and everyone was involved in preparing the facility as needed.

The group was large, since the facility was complex and various experiments were carried out. Lev Borisovich determined the vector of the research area. He was an exceptionally intelligent person. When assigning some work, as a rule, he never asked what you did, but what you had succeeded to do. He never raised his voice at anyone and it was natural, not that he had difficulty restraining himself. He was demanding, but always reasonable. Lev Borisovich was an erudite person, well versed in many related issues beyond neutron physics. When I came to FLNP as an intern, I was fascinated by the idea of the Dirac monopole. I came to him with it, he was skeptical at first, but after having listened to me, he said: interesting. He supported me, initiated a seminar and I spoke at my first seminar at FLNP not on neutron physics, but on this topic.

Throughout the whole period that Lev Borisovich maintained scientific activity and he maintained it for a very long time, he taught at the MIREA branch and even when it became difficult for him to walk, he regularly took part in the discussion of ongoing experiments and the organization of possible new ones. This is a man with an amazingly long scientific life and I think that I was very lucky that I immediately got to him. In a sense, this is a feature of our laboratory, the style set by Ilya Mikhailovich. He selected people that could, on the one hand, carry out active and in-demand activities from the point of view of the scientific community and on the other hand, these were intelligent people that treated their colleagues, especially young ones, with attention. I did not meet Fedor Shapiro, but in addition to Ilya Mikhailovich, Lev Borisovich and Yury Ostanevich are people that undoubtedly left their mark on the history of FLNP, set the style of scientific research, the style of communication, they are in the full sense the founding fathers of the Laboratory.

N.V.Rebrova: In 2002, Kristina Zhdanova and I, fourth-year students of the Department of Nuclear Physics at Voronezh State University, came to FLNP for an internship. Nikolay Gundorin was our thesis supervisor and Lev Borisovich was the leader of the scientific group which we began working in. I did my thesis experiment at the Van de Graaff accelerator and Kristina did it at the IBR-2 reactor under the direct supervision of Lev Borisovich and Nikolay Alekseevich. We were very young then and could not estimate the scientific significance of the work of Lev Borisovich and his group. Only over time, having gained experience and new knowledge, having reread their publications, did we begin to understand the complexity of their work.

Lev Borisovich was very simple in communication, kind to us, paid a lot of attention, told us about scientific tasks and problems. Despite the fact that we were very young specialists, he communicated with us as equals. We often sat in Lev Borisovich's office and he told us about neutron physics - simply, clearly, not sparing his time.

He also recalled his work on military topics before he came to JINR. He talked a lot about his elder brother Solomon Borisovich, a famous astrophysicist that had passed away early. Everyone in the group celebrated some holidays together, there was a very warm atmosphere, it was very comfortable to work. Lev Borisovich often said that he was a happy person, because in the morning, he went to work with pleasure and in the evening, he returned home with pleasure.

N.V.Simbirtseva: I joined Lev Borisovich's group in 2011 and joined new applied research at the IREN facility. At that time, the search for new research areas was relevant. Lev Borisovich suggested one such area. He agreed with the Space Research Institute of the Russian Academy of Sciences to send us geological samples collected on mountain tops to search for cosmic dust particles. We studied the isotopic composition of the samples; it was a long and quite interesting job. Unfortunately, we did not find any dust particles, yet the research became a demonstration of the capabilities of the new facility in the chosen area.

Lev Borisovich instilled in me a love for this work, because he talked about it so clearly, with such love, that physics is not difficult, very interesting, he captivated with his example. In his later years, he was on the same wavelength with the youth. Moreover, we took part in holding classes for participants of student practices from universities in Egypt, South Africa and other countries. He joked that his English was not very good. He and his friend D.N.Bell checked Lev Borisovich's English in conversations during hiking trips and David Bell confirmed: everything is clear, but incorrect. And my English was very weak then, but Lev Borisovich supported me: the main thing is not to be afraid, not to think about grammar rules. Some stupid questions from students never irritated him, he always answered in such a way that everything immediately became clear. He was an erudite person, it was always interesting to work with him: he would support and joke. In his free time, he told us about his wartime school years, when he worked at a military plant, but cherished the dream of physics. We are very grateful to him for everything.

Photo by Pavel KOLESOV
and Yury TUMANOV