3 NEW ORGANIC SCINTILLATORS WITH LARGE STOKES SHIFTS

Three new organic scintillators (PMP-410, PMP470, and PMP480) were syn thesized on the basis of 1-phenyl-3-mesityl-2-pyrazoline (PMP), Their synthesis and their polymerization in polystyrene are described, We me asured their Stokes shifts in polystyrene (similar to 1.3 eV) between their absorption maxima (PMP-410: 287 nm; PMP-470: 315 nm; PMP-480: 31 4 nm) and their emission maxima (PMP-410: 408 nm; PMP-470: 480 nm; PMP -480: 479 nm), Absorption and emission maxima, Stokes shifts, and ligh t yields of all eight pyrazoline scintillators so far synthesized are listed and are compared with results for 3-hydroxyflavone (3-HF). The advantages of these one-component dopants are discussed with respect t o the usually applied two-component (scintillator plus wavelength shif ter) dopants.