PLASMA FOCUS LIGHT SOURCE WITH ACTIVE AND BUFFER GAS CONTROL

摘要

A high energy photon source. A pair of plasma pinch electrodes are located in a vacuum chamber (10). The chamber (10) contains a working gas which includes a noble buffer gas and an active gas chosen to provide a desired spectral line. A pulse power source provides electrical pulses at repetition rates of 1000 Hz or greater and at voltages high enough to create electrical discharge between the electrodes to produce very high temperature, high density plasma pinches in the working gas providing radiation at the spectral line of the source or active gas. A fourth generation unit is described which produces 20 mJ, 13.5 nm pulses into 2 pi steradians at repetition rates of 2000 Hz with xenon as the active gas. This unit includes a pulse power system having a resonant charger charging a charging capacitor bank, and a magnetic compression circuit comprising a pulse transformer for generating the high voltage electrical pulses at 2000 Hz or greater. Gas flows in the vacuum chamber are controlled to assure desired concentration of active gas in the discharge region and to minimize active gas concentration in the beam path downstream of the pinch region. In a preferred embodiment, active gas is injected downstream of the pinch region through a nozzle (2) and exhausted axially through an exhaust port (3) in the center of the anode. In another preferred embodiment a laserbeam generates metal vapor at a location close to but downstream of the pinch region and the vapor is exhausted axially through the anode.