Thermal dependence of electrical characteristics of micromachined silica microchannel plates

Micromachined silica microchannel plates (MCPs) under development have a number of advantages over standard glass MCPs and open completely new possibilities in detector technologies. In this article we present the results of our studies on the thermal properties of silica microchannel plates (sMCPs). Similar to standard glass microchanel plates the resistance of silica MCPs was measured to change exponentially with temperature with a negative thermal coefficient of −0.036 per °C, somewhat larger than that of standard glass MCPs. The resistance also decreases linearly with the applied voltage, with the voltage coefficient of −3.1×10−4 V−1. With the knowledge of these two coefficients, our thermal model allows the calculation of the maximum voltage, which can be applied to a given MCP without inducing a thermal runaway. A typical 25 mm diam, 240 μm thick sMCP with 6 μm pores has to have the resistance larger than ∼30 MΩ to operate safely at voltages up to 800 V. With this model we can also calculate the tim...