Liquid-Filled Proportional Counter

We report properties of single-wire proportional chambers and multiple-wire ionization chambers filled with liquid xenon. Proportional multiplication is seen for anode fields > ${10}^6$ V/cm (anode-cathode voltage >1 kV for a 3.5-μm-diam anode wire). The efficiency for detecting ionizing radiation is ≅100%. The time resolution of the chambers is ±${10}^{-7\mathrm{}}$ sec. We attained a spatial resolution of ±15 μm with a multiwire ionization chamber, considerably better than that of any other real-time particle detector.