X-ray transmission through a plasma window

Traditional solid window materials used for x-ray synchrotron beamlines may introduce undesirably high attenuation, or are subject to failure under hi gh heat loads. A plasma window can in principle obviate these problems over a wide range of energies. Experiments were performed at the Brookhaven Nat ional Laboratory National Synchrotron Light Source on beamline X6A to study the transmission characteristics of a plasma window using argon as the arc gas. Measurements were made around the Ar K edge and far from resonance. T he "white-line" absorption at the K edge was actually suppressed during arc operation as compared to room temperature gas at the same pressure. This i s attributed to the high degree of ionization in the plasma. The relative s trength of the white line to the edge jump does not seem to be a strong fun ction of arc current at the argon K edge. Away from resonance (similar to3 times the edge energy) x-ray attenuation was negligible. (C) 2001 American Institute of Physics.