Papers

On the first Townsend coefficient at high electric field

For the first time it is shown and experimentally confirmed that gas gain in wire chambers at very low pressure become higher on thicker wires at the same applied high voltage. This is a consequence of the fact that the first Townsend coefficient at high reduced electric field depends almost entirely on the electron’s mean free path.

Gas gain on single wire chambers filled with pure isobutane at low pressure

The gas gain of single-wire chambers filled with isobutane, with cell cross-section 12x12 mm and wire diameters of 15, 25, 50 and 100 μm, has been measured at pressures ranging 12-92 Torr. Contrary to the experience at atmospheric pressure, at very low pressures the gas gain on thick wires is higher than that on thin wires at the same applied high voltage as was shown in [1]. Bigger wire diameters should be used in wire chambers operating at very low pressure if multiple scattering on wires is not an issue.