The results of studies of optical, photoluminescence, and scintillation characteristics of 4-amil-4'-cyanobiphenyl liquid crystals are presented. Those crystals Showed a scintillation light yield of similar to 35% of anthracene, fluorescence decay times of 4 and 14 ns, and a maximum of the emission spectrum of similar to 400 nm. The light yield of a solution of a liquid crystal and the R6 green scintillation additive is similar to 120% of anthracene. The light yield of a frozen solution at -120 degrees C was found to be 2.5 times higher than at 20 degrees C. An oriented liquid crystal has an appreciable level of emitted-light polarization. The maximum emitted light intensity in an oriented liquid crystal is perpendicular to the direction along which most long molecular axes are oriented. The possibilities of employing scintillating liquid crystals for improving the characteristics of existing particle detectors and designing new controllable detectors are considered.

Liquid scintillator, based on 1-methylnaphthalene and a new solvent IPN, which emitting in the green spectral range, were studied. The scintillation efficiency in vacuum was 22-32% higher compared to the level in air, and the intrinsic light yield of the scintillators reached 41-50% of the yield from anthracene. The increased level of the scintillation efficiency was virtually retained in the atmosphere of inert gases (Ne, Ar, and CO2). The light yield of liquid scintillators based on 1-methylnaphthalene (in air) and IPN (in vacuum) were virtually independent of the temperature in the interval from -5 to +20 degrees C. Liquid scintillator on the basis of 1-methylnaphthalene and a scintillation additive R6 (concentration 3 g/l) also exhibited a highly stable light yield (+0.024%/K) in the temperature interval from +20 to +60 degrees C.

Temperature dependence of the light yield of 1-methylnaphthalene based scintillators emitting in the green spectral range was studied in the liquid and frozen states. The light yield of the scintillator frozen at -120 degrees C in vacuum increased 2.2-3.3 times compared to the room-temperature value in air, and reached 88-118% of the level for anthracene. All scintillators cooled to -120 degrees C, and then heated to 20 degrees C exhibited a hysteresis in the temperature variation of the light yield. The duration of signals from the frozen samples in air was somewhat longer compared to that at room temperature. The light yield of scintillators studied was sensitive to the ionization density.

The results of investigations of scintillation properties of new SiO2-aerogel-based scintillators are presented. The aerogels are simultaneously saturated with Ar and 1-methylnaphthalene-based liquid scintillators. When luminescence is excited in the new scintillator samples by high-energy particles, a light yield of 10.9% of the anthracene level is attained.

This article presents a comparative study of scintillation and radiation characteristics for a series of new and known plastic scintillators. About 70 new scintillators have been measured. Polystyrene scintillators containing 20% 1-methylnaphthalene + 2% pTP + 0.05% POPOP and 20% 1-methylnaphthalene + 2% pTP + 0.05% POPOP + 0.02% K-27 revealed the maximum radiation resistance, about 7–9 Mrad.