Current response characteristics of microchannel plates x-ray detector using synchrotron radiation (0.6–2 keV and 5–20 keV)

The characteristics of microchannel plates (MCPs) for detection of x rays have been investigated using synchrotron radiation in the energy ranges from 0.6 to 2.0 keV and from 5 to 20 keV. Microchannel plates are operated under the condition of an unsaturated pulse-height distribution mode. The current response curve of MCPs is measured continuously with x-ray energy variation for the first time. The experimental result of some discontinuous jumps in the response is obtained at the energies corresponding to the absorption edge of the MCP materials. In the low-energy range (hν<2 keV), the dependence of the current response to the incident angle of x rays to the channel axis θ is measured to be proportional to cot θ, which is interpreted by the x-ray absorption near the surface of MCP channel wall. While, in the high-energy range (hν>5 keV), a weak dependence on θ is observed, and is attributed mainly to the penetration of x rays through multiple channels.