New scintillating media based on liquid crystals for particle detectors

The study results of optical, photoluminiscent and scintillation properties of a liquid crystal 4-pentyl-4'-cyanobiphenyl are presented. The scintilla tion light output of this liquid crystal is about 35% of crystal anthracene , its main decay time constants are 4 and 14 ns, and the maximum of light e mission spectrum is about 400 nm. The light output of a dissolution of gree n emitting light scintillation dopant R6 in the liquid crystal is about 120 % of crystal anthracene. The light output of the frozen dissolution measur ed at - 112 degrees C is about 2.5 times higher as observed at + 20 degrees C. In the uniaxially oriented liquid crystal, the predominant intensity di rection of emitted light is pointed perpendicular to the liquid crystal dir ector and an appreciable part of the emitted light is elliptically polarize d. The possibility to use scintillation properties of liquid crystals is co nsidered both for the improvement of existing particle detector characteris tics and for the creation of new gated particle detectors. (C) 2000 Elsevie r Science B.V. All rights reserved.