Abstract

An unshielded microchannel plate (MCP) detector with an ultrafine pore diameter of 2 μm was irradiated by an electron beam to determine the detection efficiency of electrons for creating detector signals, or counts. Tested electron energies spanned a range of 3 kiloelectron volts (keV) to 28 keV. Higher detection efficiencies were measured at the lower end of this energy range, 0.376 counts per incident electron at 3 keV down to 0.155 at 15 keV with an increase to 0.217 at 18 keV and then another decrease down to 0.15 counts per incident electron at 28 keV. The increase at 18 keV is attributed to primary electron interaction with the L shell electrons of lead (Pb), leading to an increase in secondary electron and X-ray generation within the MCP and thus an increase in detection efficiency. For the electron beam directed normal to the MCP surface, the lowest efficiency of 0.15 counts per incident electron was observed at 28 keV. Detection efficiency was also tested as a function of incident angle with angular steps of 5°. Detection efficiency was more sensitive to the angle of incidence as the incident electron energy decreased. The detection efficiency at 3 keV decreased from 0.376 counts per electron at the zero degree angle (normal incidence to MCP surface) to 0.027 counts per electron at an incident angle of 50° (average in both orientations). At 28 keV, the decrease in detection efficiency as a function of increasing angle was less pronounced, ranging from 0.15 counts per electron at zero degrees to 0.08 counts per electron at 50° (average in both orientations). Experimental data showed lower detection efficiencies compared with previously published data.

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.