New system for secondary electron detection in variable-pressure scanning electron microscopy

Area of Science:

• Materials Science
• Physics
• Analytical Chemistry

Background:

• High-pressure scanning electron microscopy (HPSEM) requires specialized detectors capable of operating at pressures up to 10 mbar.
• Conventional secondary electron detectors often face limitations in gas handling and longevity under such conditions.
• Existing systems may struggle with gas leakage and reduced operational lifespan.

Purpose of the Study:

• To present a novel secondary electron detection system for HPSEM.
• To address challenges of gas leakage and detector lifespan in high-pressure environments.
• To leverage the advantages of scintillator detectors at elevated gas pressures.

Main Methods:

• Development of a two-stage detector head incorporating a scintillation Everhart-Thornley detector and a microsphere plate.
• Integration of a differential pumping system to manage vacuum levels between stages (below 0.1 mbar).
• Asymmetric arrangement of the detector system components.

Main Results:

• The novel system effectively detects secondary electrons across a wide pressure range (high vacuum to 10 mbar).
• The asymmetric design demonstrated reduced gas leakage through the microsphere plate.
• The system is expected to offer an extended operational lifespan for the detector plate.

Conclusions:

• The presented secondary electron detection system is suitable for HPSEM applications.
• The design effectively mitigates gas leakage and enhances detector durability.
• This innovation supports advanced microscopy at higher gas pressures.