The efficiency of halogen-quenched geiger-counters for X-rays

The efficiency of two argon-bromine counters is determined for Mo-Kα, Cu-Kα and Cr-Kα quanta as a function of the overvoltage and as a function of the distance from the axis where the quanta are absorbed. The efficiency drops sharply at greater distances from the wire. This effect is partially ameliorated at higher overvoltages. The more energetic X-ray quanta show a higher relative efficiency in the outer regions. The explanation is to be found in the electronegativity of the halogens.