Analysis of the memory effect in a nitrogen-filled tube at 6.6 mbar pressure for different cathode materials using the time delay method

The memory effect, due to postafterglow survival of some species which affect subsequent breakdown, was analyzed from the behavior of memory curves. In early afterglow, up to several tens of a millisecond, the memory effect in nitrogen is a consequence of the presence of positive ions formed by the collision between metastable molecules and highly vibrationally excited molecules remaining from the previous discharge. In late afterglow, the memory effect is due to N(4S) atoms created during the previous discharge and in early afterglow. When the atom density is reduced enough the breakdown is initiated by cosmic rays which always exists. In late afterglow in nitrogen the memory effect is very sensitive on cathode material