Existing formulas for correcting counter data for "missing" are found to apply to conditions which often cannot be realized in practice. Let ${\tau }_c$, ${\tau }_i$, and ${\tau }_r$ be the recovery times of the counter, amplifier and recording unit. It is shown that excellent performance can be obtained by using an amplifier which controls the voltage recovery of the counter so that ${\tau }_c={\tau }_i=\mathrm{constant}$. When the counter receives $f$ particles/sec., capable of activating it, the efficiency of the entire apparatus is ${(1+f{\tau }_i)}^{-1\mathrm{}}$ if ${\tau }_r<{\tau }_i$. It is $\frac{e^{-f({\tau }_r-{\tau }_i})}{(1+f{\tau }_i)}$ if ${\tau }_r>{\tau }_i$ and the recorder is not influenced by any impulse which reaches it while it is operating.

• Received 17 June 1937

DOI:https://doi.org/10.1103/PhysRev.52.322