Gridless electron trap for a high-duty cycle magnetic bottle time-of-flight spectrometer

Abstract

Magnetic bottle time-of-flight electron spectrometers traditionally combine high detection efficiency with high energy resolution in low duty cycle, pulsed experiments. We proposed a new electron-trap design in which photoelectrons oscillate between a magnetic and an electrostatic mirror. Ideally, they accumulate in the trap for several microseconds before the electrostatic mirror is switched off. This opens up new applications at continuous or quasi-continuous light sources, such as synchrotron radiation facilities. In the original setup, we achieved high energy resolution using planar metal grids for the electrostatic mirror. However, the finite transmission of the meshes and the high oscillation frequency of electrons limit the duty cycle. In the first gridless design proposed herein, the energy resolution is lower, but the storage time exceeds 40 μs. Thus, at an operating frequency of 100 kHz (≙ 10 μs), 40% of all electrons emitted in 4π sr may be analyzed.