The Plasma Window: a Windowless High Pressure-Vacuum Interface for Various Accelerator Applications*
Proceedings of the 1999 Particle Accelerator Conference, New York, 1999 THE PLASMA WINDOW: A WINDOWLESS HIGH PRESSURE-VACUUM INTERFACE FOR VARIOUS ACCELERATOR APPLICATIONS* A.I. Hershcovitch, E.D. Johnson, Brookhaven National Laboratory, Upton, NY 11973 R.C. Lanza, Massachusetts Institute of Technology, Cambridge, MA 02139 Abstract The Plasma Window is a stabilized plasma arc used as windowless gas target system removes these limitations an interface between accelerator vacuum and pressurized by removing all physical boundaries between the targets. There is no solid material introduced into the accelerator and the gas target. The gas target itself poses beam and thus it is also capable of transmitting particle no limitations on the beam since it can be constantly beams and electromagnetic radiation with low loss and cooled and replenished. of sustaining high beam currents without damage. A novel apparatus, which utilized a short plasma arc, Measurements on a prototype system with a 3 mm was successfully used to provide a vacuum-atmosphere diameter opening have shown that pressure differences interface as an alternative to differential pumping, and of more than 2.5 atmospheres can be sustained with an an electron beam was successfully propagated from input pressure of ~ 10-6 Torr. The system is capable of vacuum to atmospheric pressure.[1,2] scaling to higher-pressure differences and larger Windowless gas targets, for neutron production, have apertures. Various plasma window applications for been constructed using differentially pumped gas synchrotron light sources, high power lasers, internal systems with a series of rotating valves. Although these targets, high current accelerators such as the HAWK, systems have demonstrated the feasibility of such ATW, APT, DARHT, spallation sources, as well as for a techniques, they are limited to use with pulsed number of commercial applications, will be discussed.
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