New scintillation transparent ceramics Y₃Al_2.5Ga_2.5O₁₂:Ce, Mg has been produced and evaluated for the first time. The material possesses a density of 5.17 g/cm³, a highlight yield of 44,000 ph/MeV, and an effective scintillation kinetics decay constant of 47 ns. This unique combination of the parameters makes it superior to YAG:Ce. Production of the material does not include tooling from precious materials, and the rate of the crystalline mass production is not limited by the pulling rate of the crystal growth process. It can be quite prospective to upgrade the detection units of a variety of X-ray imaging devices. The mechanism of the scintillation light yield enhancement and kinetics shortening in the material are discussed as well.

Lightweight satellites, which monitor different kinds of ionizing radiation in the Earth's orbits, need lightweight detectors as well. For the first time, the detecting capabilities of new high light yield and fast scintillation materials of garnet structure, Gd3Al2.5Ga2.5O12:Ce,Mg (GAGG:Ce,Mg-HL) and Y3Al2.5Ga2.5O12:Ce,Mg (YAGG:Ce,Mg-HL), which were produced in the form of single crystals and ceramics, have been evaluated to construct miniature detectors of neutrons. Scintillators have a light yield over 45 000 ph/MeV; at that, Gd-less material has twice as short scintillation kinetics. Both achievements were obtained due to the combined variation in the Al/Ga ratio and Mg doping of the materials. When detecting thermal and epithermal neutrons, YAGG:Ce,Mg-HL will be used as a γ-ray monitor to extract background from the data acquired by GAGG:Ce,Mg-HL. Fast neutrons will produce an identical set of charged secondaries in the materials, which can be distinguished by the pulse shape discrimination method. This finding allows us to construct a miniature detector of neutrons to equip even nanosatellites to monitor space and the secondary neutrons.

This paper presents the results of Monte Carlo modelling of the sensitivity of the lithium containing detectors CLYC, NaIL, CLLB to thermal neutrons. The difference between the sensitivity and the neutron freepath depth of the CLYC scintillator enriched and unenriched with the 6Li isotope is shown. The analysis of the distribution of alpha particles and neutrons in the scintillator volume is performed, showing the inefficiency of the unenriched scintillator due to the fact that not all neutrons react with the crystal material. Mathematical modelling by the Monte Carlo method of the scintillator sensitivity and its comparison with respect to the irradiation direction has been carried out. It is shown that for the scintillator in the face and side geometry with the size more than 38 mm the difference in sensitivity at change of the neutron flux direction is connected only with the scintillator cross section and 6Li concentration with the same value of the specific sensitivity. The obtained model results were compared with available experimental data for NaIL and CLLB scintillators, which showed the reliability of the developed models and calculation methods.