Abstract
It is shown that the constant D of transverse diffusion of drifting electrons in gases depends on the magnetic field B or the cyclotron frequency ω = ( e m)B in such a way that the reduction factor is D(0) D(B) = 1 + ω2τ1
2 for small B and D(0) D(B) = C + ω2τ2
2 for large B. The measurements were done between B = 0 and 7 kG, using a time projection chamber. The gas was 91% argon and 9% methane at 1 atm, the drift field 115 V/cm.