Micelle size effect on Fe-55 liquid scintillation efficiency

• No efficiency reductions attributable to the micelle size effect were observed.
• Calculated micelle corrections are small compared to other uncertainties.
• Metal ions did not affect micelle size or fluorescence quenching.
• Tracing 55Fe efficiencies with 54Mn reduced model dependence.

We used efficiency tracing techniques to study the micelle size effect on liquid scintillation counting of the electron capture nuclide, 55Fe. We determined micelle hydrodynamic diameters for specific LS cocktails via dynamic light scattering, and sought trends in efficiencies as a function of micelle size. The presence of Fe3+ or Mn2+ ions in the cocktails did not significantly affect micelle sizes or fluorescence quenching. We did not detect any reductions in counting efficiencies due to the micelle size effect.