Performance of a low-pressure Micromegas-like gaseous detector

We studied the properties of low-pressure Micromegas detectors in which the length of the amplification gap was slightly increased to improve the attainable gas gain. Two detectors with amplification gaps of 200 and 400 μm were constructed and operated at gas pressures below 60 Torr. Large gas gains (104–105) and fast signals (100–200 ns duration) were observed and the possibility of obtaining an ion backflow as low as 10−4 was demonstrated. These properties, combined with the simple and robust structure of the detector which result from the increased length of amplification gap, make it an attractive choice for applications which benefit from low-pressure operation.