High pulse radiating power excilamps

Abstract

Summary form only given as follows. This paper reports on the pulse sources of spontaneous UV and VUV radiation with high power, developed on the basis of volume pulse high-current discharges at high specific power of excitation (~100 MW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> ) and pressures (up to 12 atm) in inert gases and their mixtures with halides. In the experiments, we used a set-up, forming a volume discharge without preionization. The set-up included a primary capacitive store, a pulse transformer, a coaxial line with a wave impedance of 10 or 20 Omega, a peaking spark gap, a gas diode, and a system for working gas mixture preparation and evacuation. First developed set-up presents by itself a source with emitting area of a radiator of greater than 20 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The duration of a generator voltage pulse at a matched load is ~50 ns. The discharge shape was like a truncated cone with a base on the anode. The diameter of the emitting area of the near-cathode discharge plasma was ~6 cm, and ~8 cm near the grid anode; the interelectrode distance was 4.5 cm. The maximum radiating power on Xe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> * dimmers at 140-200 nm to the full spatial angle was obtained at the pressure of Xe of 760 torr amounting ~8 MW. The radiation pulse FWHM was of no greater than ~100 ns, and the power density at excitation pulse duration of tens ns was ~2times10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The investigations exhibit that the Xe dimmers radiating power obtained by using the above-mentioned set-up increases with the growth of pressure of Xe until the value of 1 atm. The characteristics of radiant emittance of the volume high-current discharge plasma in inert gases at pressure greater than 1 atm was investigated by using a RADAN-220 pulser with the voltage pulse amplitude of 220 kV and pulse duration at a matched load of ~2 ns. The width of the pulse leading edge was ~0.5 ns. A flat anode and a cathode with a small-curvature radius provided the electric field gain in the near-cathode region. Interelectrode distance ranged as 4-16 mm. The most homogeneous discharge was obtained in the high-pressure He. For the first time, a subnanosecond electron beam of fast electrons was registered in He at the pressure of 12 atm. The beam current pulse duration at a half-height was no greater than 100 ps. At Xe pressures greater than 3-4 atm there were observed the discharge contraction channels. At the same time, the high-power radiation of Xe dimmer band was recorded at the pressures less than 12 atm. Though having as a bit decreased radiant energy, the radiating power increased with the growth of Xe pressure, comprising ~1 MW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> at the pressure of 12 atm. In this case, the radiation pulse FWHM was eight ns.