Interview conducted in October 2021

German Kulin – master of physics, senior researcher at Sector of Investigations of Neutron Fundamental Properties, Division of Nuclear Physics.

When I studied at Tver State University, professor Viktor A. Druin, the dean of our faculty, had a large experience working in Dubna. He remained in contact with the Joint Institute for Nuclear Research, mainly with the Laboratory of Nuclear Reactions. I was in my fourth year when I learned that there was an opportunity to try myself at JINR. I was interested. Viktor A. Druin organized an excursion for the interested students of our course. Thus, in February 2001 I came here to work on my bachelor's thesis, and a year later on my graduate thesis.
When I arrived in Dubna, I had a choice: either to work in the Laboratory of Nuclear Reactions, or here – in the Frank Laboratory of Neutron Physics. I favored FLNP and never regretted it. At that time, Valery N. Shvetsov was the head of the Division of Nuclear Physics at FLNP. He personally spoke with me about the agenda of the department and organized a meeting with group leaders interested in students, asking them to speak about their work. I was deeply interested in fundamental neutron optics, which the group of Alexander Frank was engaged in. It has determined for many years what I was doing, and still doing now. I took part in an experiment at Institut Laue Langevin in Grenoble, devoted to the optics of strongly absorbing media. The results of this experiment formed the basis to my master thesis. Among my classmates, Igor Papushkin also got a job here at the Division of Condensed Matter Research and Developments.
My scientific activity is now devoted to non-stationary neutron optics. As well as studies of the phenomenon of non-stationary diffraction of neutrons by moving grids and surface acoustic waves (which have been ongoing for several years), and studies of the effects arising from the interaction of a neutron wave with objects moving with acceleration.

Now we are taking the very first steps in a large project to create an ultracold neutron (UCN) source at a pulsed reactor. For this, the method of pulsed accumulation of neutrons in a trap and temporal focusing of neutrons will be used. The idea of temporal focusing is based on the very physics that we have been studying for quite a long time, the non-stationary diffraction of neutrons by a moving grid. This should give us the opportunity to obtain a significant gain in the UCN flux and the hope of creating a UCN source of the world class.
I believe that in our Laboratory everyone can find interesting physics problems for themselves. Frank Laboratory of Neutron Physics at the Joint Institute for Nuclear Research occupies one of the leading positions in Russia, and it is also in good standing abroad. Our own reactor enables young specialists to gain practical experience of work, to really feel physics with their own hands.