What key factors affect scintillation cocktail performance?
A. For optimal detection sensitivity and accuracy, a good scintillation cocktail should have: 1) High Counting Efficiency: Counting efficiency is the percentage of input radioactivity detected by a scintillation counter. All radioactive samples suffer from some degree of quenching, and counts per minute (CPM) do not equal the amount predicted by decay rate (reported as DPM). Hence, the % counting efficiency is defined as CPM divided by DPM times 100%. 2) High Aqueous Capacity: This refers to the amount of water a cocktail can contain and still retain good counting efficiency. A high aqueous capacity basically ensures that the mixture remains homogeneous and does not partition into two phases. If separation occurs, the radioactive material becomes unevenly distributed between these phases, or quenching by the aqueous overload can occur, thereby reducing the detectable counts. 3) Resistance to Chemiluminescence/Phosphorescence: some cocktails may be light sensitive or have an intrinsic p
