Excitation and emission bands of hydrogen atoms in a solid neon matrix

Experimental setup for the growth of solid crystals of inert gases for particle detection

Low energy threshold detectors are necessary in many frontier fields of the experimental physics. In this work, we present a novel detection approach based on pure or doped matrices of inert gases solidified at cryogenic temperatures. The small energy release of the incident particle can be transferred directly (in pure crystals) or through a laser-driven ionization (in doped materials) to the electrons of the medium that are then converted into free electrons. The charge collection process of the electrons that consists in their drift within the crystal and their extraction through the solid-vacuum interface gives rise to an electric signal that we exploit for preliminary tests of charge collection and crystal quality. Such tests are carried out in different matrices of neon and methane using an UV-assisted apparatus for electron injection in crystals.

Dynamics of localized excitations from energy and time resolved spectroscopy

The electronic structure and the excited state relaxation phenomena in condensed rare gases have been studied by absorption spectroscopy, photoelectron spectroscopy, and time resolved luminescence spectroscopy, all using selective excitation by monochromatized synchrotron radiation. Radiationless and radiative electronic transitions in excited states and the rearrangement of surrounding matrix atoms will be discussed for excited rare gas atoms in rare gas matrices. Furthermore, experimental results concerning the scattering of excitons within the free exciton branches, localization of excitons, relaxation within the self-trapped exciton states, and energy transfer to guest atoms and boundaries will be presented.