Speaker
Mr
Evgeniy Unzhakov
(Petersburg Nuclear Physics Institute)
Description
The modern theoretical models of ``invisible'' axion describe its interaction with ordinary matter in terms of effective coupling with nucleons ($g_{AN}$), electrons ($g_{Ae}$) and photons ($g_{A\gamma}$).
Axion coupling to atomic nuclei ($g_{AN}$) makes it possible for axions to be resonantly emitted or absorbed during the nuclear transitions of magnetic-type.
Particular isotopes possess the low-energy nuclear excited states ($\sim 1$~keV), thus making it possible to test the solar axion flux.
The resonant absorption of axions within the target material will lead to population of that excited state, whose following de-excitation will lead to the excess amount of X-ray with the corresponding energy.
A series of low-background experiments were performed with solid state ($^{7}$Li, $^{57}$Fe, $^{169}$Tm)
resulted in setting and following gradual improvement of the upper limits on the axion coupling constants and $g_{A\gamma}$, $g_{Ae}$ and $g_{A\gamma}$.
It soon became evident that in order to improve sensitivity of experiment one has to significantly increase the target mass, but in that case a self-absorption of the X-rays by the target bulk cancels out the intended advantages.
This challenge could be solved by introducing the target material inside the active volume of the detector.
The following step involved proportional gas chamber, filled with $^{83}$Kr gas located at the underground facility at Baksan Neutrino Observatory.
At the moment a principally new approach is being developed that involves the creation of cryogenic bolometer setup with Tm-containing crystal at its core.
Primary authors
Prof.
Alexander Derbin
(Petersburg Nuclear Physics Institute NRC KI)
Mr
Evgeniy Unzhakov
(Petersburg Nuclear Physics Institute)
Dr
Ilia Drachnev
(PNPI NRC KI)
