POPOP or 1,4-bis(5-phenyloxazol-2-yl) benzene is a

scintillator A scintillator is a material that exhibits scintillation, the property of luminescence, when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate (i.e. re-emit the absorbed ...

. It is used as a

wavelength shifter A wavelength shifter is a photofluorescent material that absorbs higher frequency photons and emits lower frequency photons. The material absorbs one photon, and emits one or multiple lower-energy photons. The relaxation time of the excited molecul ...

(also called a "secondary scintillator"), which means that it converts shorter wavelength light to longer wavelength light. Its output spectrum peaks at 410 nm, which is

violet Violet may refer to: Common meanings * Violet (color), a spectral color with wavelengths shorter than blue * One of a list of plants known as violet, particularly: ** ''Viola'' (plant), a genus of flowering plants Places United States * Viol ...

.Mechanism of Liquid Scintillation Counting
National Diagnostics, retrieved 24 Sept 2007 POPOP is used in both solid and liquid organic scintillators.

References

Phosphors and scintillators Oxazoles {{organic-compound-stub