- Mixed crystal luminescence study.
This part of activity directed to the modification of the crystal lattice and zone structure by the transfer to the solid solutions with mutual cation, such as LGSO crystals. Scientific goals are the study of the luminescence nature and ability to manage emission parameters by the host structure modification. An important part of the study relates to the luminescence center (Ce3+ ions) sites modification in the crystal lattice. This is an important aspect of scintillation material optimization.
- Low temperature luminescence study and cryogenic scintillators search.
The quest for dark matter is one of the most pressing challenges to cosmology and astro?particle physics. From a number of astrophysical observations and from the cosmic microwave background radiation experiment, we have learned that the universe contains about 30% matter and 70% dark energy. In case the dark matter consists of exotic particles which interact weakly with ordinary matter, so?called weakly interacting massive particles (WIMPs), they should be detectable in principle.
The luminescence study of potential candidates for the dark matter search scintillation materials is the general aim of the proposed experiment. Partners propose to study low temperature luminescence properties and efficiency of energy transfer in the region of first multiplication threshold of ZnWO4 and ZnMoO4 based crystals as well as their solid solutions to optimize materials composition from the point of view their use for the dark matter search. Based on time?resolved VUV spectroscopy and TCL technique we will investigate the nature and scintillation perspectives of different types of point defects (intrinsic, extrinsic and combined) and energy transfer mechanism in LiF. This knowledge will help to control the scintillation detector parameters by using doping and annealing in different atmospheres.
Partners have studed three types of crystals:
- tungstates - ZnWO4, ZnWO4:Me1+, ZnWO4:Me3+, ZnWO4:Me1+Me3+, and MgWO4
- molybdates - ZnMoO4, ZnMoO4:Me1+
- halide - LiF crystal
- Energy transfer to the nano particles uploaded into plastic scintillators.
This part of the study has two main steps (problems) that have to be resolved with the help of precise luminescence study. These are – ability to upload inorganic nanoparticle in the organic matrix with the boundaries transparent for primary excitation (in particular – electrons) and the study of the energy transfer from particles to the medial and in the opposite direction. Partners have to check the size effect importance for this phenomena also.
- Comparative crystal growth with different technique use.
In the frame of this activity we plan to grow the same crystal by the different technique. Lyon University has micro?pulling down technique for the fast crystallization rate growth. ISMA utilize conventional CZ technique. So partners have to compare crystal performance and functional properties of the same materials after various crystallization procedures.