recently reported a very interesting way in which to endow a Geiger-Mueller counter with directional properties.
He finds that small beads of glass mounted on the wire of a counter filled with a self-quenching mixture effectively confines the discharge to those sections of the tube traversed by the original ionizing ray. Thus the pulse size from the wire is proportional to the number of segments traversed and'is an indication of the path taken by this ray.
The ability to limitthe discharge in self-quenching counters in this way is a consequence of the fact that in these counters not only is the active discharge confined to the immediate vicinity of the wire, as in all counter action, but also to the fact that no photoelectrons are formed in remote parts of the counter as a consequence of photons originating in this region. Emmett L. Hudspeth, using an arrangement employed by the author for studying the distribution of photons in time during the discharge in a non-self-quenching mixture,~found this absence of photoelectrons in the case of the self-quenching gas.