Seminars

Remembering the history

On 20 September, a seminar of the Department of Nuclear Physics "Gravitational spectrometry of ultracold neutrons. A brief historical overview and the current state" was held at FLNP JINR.

An analysis based on the papers published over almost a quarter of a century was made by M.A.Zakharov (Sector of research on fundamental properties of the neutron of FLNP). Anticipating his speech, the group leader A.I.Frank explained that the seminar falls outside the usual range of reporting speeches and is of an educational nature. Its goal is to "resurrect" information about significant and interesting events. In the Department of Nuclear Physics of FLNP, a team on ultracold neutrons was developed, mainly consisting of young people. They decided to combine these two phenomena - the history of research and the educational component.

AM.A.Zakharov started the story with the first paper published by FLNP staff members in 1978 that predicted the phenomenon of the occurrence of neutron energy levels in a gravitational field above a mirror. The first experimental observation was carried out only in 2002 at the reactor in Grenoble by V.V.Nesvizhevsky (Laue-Langevin Institute) together with the colleagues from FLNP. The paper caused a discussion and there was a need to further improve the accuracy of the experiment and to analyze the results. An alternative implementation of this experiment was carried out by H.Abel's group (QuBounce project); they implemented the last experiment in 2014. A record accuracy of neutron energy measurements was obtained at a level of 10^-17 eV.

AUCN resonance gravitational spectrometry can be used in fundamental research, such as, when testing prototypes of dark matter and dark energy and searching for the fifth type of interaction.

AThe speech raised numerous clarifying questions from the participants. Summing up the seminar, V.N.Shvetsov noted: "The first pancake" turned out to be... quite normal. We are waiting for continuation from other groups of the department. It is necessary to return educational seminars, as V.K.Ignatovich and even earlier F.L.Shapiro had spoken about more than once."

Olga TARANTINA