Volume recombination parameter in ionization chambers.

The parameter m2 governing the volume recombination in ionization chambers has been measured under conditions which allow strict application of the basic theory. The method consists of measuring the ratio of ionization currents I(V1) and I(V2) obtained at two given voltages V1 and V2 as a function of I(V1). The value of m2 is derived from a linear extrapolation to zero current. Several pairs of voltages (V1, V2) were used. The value of m2 obtained in this work is 3.97 x 10(14) s m(-1) C(-1) V(2) with a relative uncertainty of 1.7%. The dependence of m2 on atmospheric conditions has also been investigated.