Interaction of Charged Particle Beams with Pre-Ionized Channels

摘要

A Monte Carlo Fokker Planck Code is used to investigate the scattering loss of particles from a relativistic electron beam propagating in a low pressure air channel. Two special cases are examined. The first corresponds to an experiments in which a one cm radius, 90 KeV beam propagates in hydrogen channel of the same radius, 50 cm long with a density of 10 cm and a temperature of 0.5 eV assuming the interaction to take place only with the charged particles of the medium. It is shown that the beam will traverse such channel if the ionization drop s below 20% noting that for such parameters the channel pressure corresponds to few tens of militors. The second case corresponds to what is referred to as the Ion Focused Regime where the pressure is about 0.1 torr. Scattering of beam particles by both neutral and charged particles is taken into account in this case as well as multiple scattering form neutral targets. It is shown that transmitted fraction is linearly proportional to the square of the channel radius, and the probability of multiple scattering increases with increasing channel radius.