The present invention relates to a sensor for electron detection emitted from an object to be used with a charged particle beam column being operated at a certain column and wafer voltage. The sensor is configured and operable to at least reduce interaction of negative ions with the active area of the sensor while minimizing electrons energy loss. The sensor is also configured and operable to minimize both gradual degradation of a cathodoluminescence efficiency of the active area and dynamic change of cathodoluminescence generated during operation of the sensor and evolving throughout the scintillator's lifetime.