Double-pass cylindrical mirror energy analyser has how many mirrors?

double-pass-cylindrical-mirror-energy-analyser-has-how-many-mirrors

Double-pass cylindrical mirror energy analyser has how many mirrors?

A. One

B. Two

C. Three

D. Four

I got this question in exam.

I need to ask this question from Instrumentation for Electron Spectroscopy in chapter Electron and Ion Spectrometers of Analytical Instrumentation

Right choice is B. Two

Explanation: Double-pass cylindrical mirror energy analyser has two mirrors. It is commonly used in electron spectroscopy.