Studies of electron avalanche behavior in liquid argon


Kim J., Dardin S., Jackson K., Kadel R., Kadyk J., Peskov V., ...More

IEEE Nuclear Science Symposium, California, United States Of America, 4 - 10 November 2001, pp.119-123 identifier

  • Publication Type: Conference Paper / Full Text
  • City: California
  • Country: United States Of America
  • Page Numbers: pp.119-123
  • Bursa Uludag University Affiliated: No

Abstract

Electron avalanching in liquid argon is being studied as a function of voltage, pressure, radiation intensity, and the concentrations of certain additives, especially xenon. The avalanches produced in an intense electric field at the tip of a tungsten needle are initiated by ionization from a moveable americium (Am-241) gamma ray source. Photons from xenon excimers are detected as photomultiplier signals in coincidence with the current pulse from the needle. In pure liquid argon the avalanche behavior is erratic, but the addition of even a small amount of xenon (less than or equal to100ppm) stabilizes the performance. Similar attempts with neon (30%) as an additive to argon have been unsuccessful. Tests with higher energy gamma rays (Co-57) yield spectra and other performance characteristics quite similar to those using the Am-241 source. Two types of signal pulses are commonly observed: a set of pulses that are sensitive to ambient pressure, and a set of somewhat smaller pulses that are not pressure dependent.