For a liquid scintillator, you want to use toluene + p-terphenyl + POPOP. The latter two are dissolved in the toluene at a proportion of 5g and 0.1g/liter, respectively. This is a standard, fairly high output mixture for liquid scintillators. Watch out for the toluene, as it is not too good for you (don't breathe the fumes, avoid skin contact).
Created on Monday, June 11, 2001 9:08 PM EDT by Richard L. Hester