Characteristics of Micromegas detectors at high temperature

The behaviour of two small resistive-strip bulk-Micromegas detectors has been studied up to a temperature of approximately 55$^\circ$C. A strong increase of the dark current is observed at temperatures higher than 40 degrees. Keeping the gas at room temperature and varying the detector temperature, the measurements show that the increase of the dark current is primarily related to the detector temperature. The results of a dedicated study of the resistivity of the pillar material as a function of temperature and humidity explain the observed effects. In addition to these studies, the detector response as function of temperature is presented showing that the detector operates correctly up to the highest temperature achieved in this test.