Practice question

Tritium and carbon-14 emit very weak beta particles around 18 keV and 156 keV respectively, which are readily absorbed by detector windows and air. Solid detectors and Geiger tubes have poor efficiency for such low energies. Liquid scintillation counting dissolves sample directly in organic cocktail containing primary fluors like PPO and secondary wavelength shifters. Beta energy excites solvent molecules, transferring energy to fluors emitting light photons counted by photomultiplier tubes. Close molecular contact ensures minimal self-absorption, making liquid scintillation optimal for detecting low-energy beta emitters in biological tracer work.