Observing single electron pulses provides insight into the mechanism
that leads to sudden high current jumps (breakdown) in aged
wire chambers. This single electron activity is found to be
consistent with the Fowler-Nordheim equation for field emission
of electrons from a cathode surface in a high electric
field. The high electric field arises from the positive ion
buildup on a very thin insulating layer on the cathode
surface. A model is presented to explain the transient behavior
of single electron pulses in response to abrupt changes in
chamber ionization, as well as the steady state rate during a
long term aging run. The model is based on properties of the
insulating layer (dielectric constant, conductivity, and
hole-mobility) as well as the Fowler-Nordheim equation.
Abstract: