Development of a portable time-of-flight mass spectrometer prototype using a cold electron source

Area of Science:

• Analytical Chemistry
• Instrumentation Science

Background:

• Developing portable time-of-flight mass spectrometers (TOF MS) faces challenges with ionization sources and vacuum systems.
• Existing technologies limit the miniaturization and field applicability of TOF MS.

Purpose of the Study:

• To investigate the feasibility of a portable TOF MS using a novel cold electron source (CES) and pulse valve.
• To overcome fundamental obstacles in developing compact and efficient mass spectrometry instrumentation.

Main Methods:

• A cold electron source (CES) was developed using a microchannel plate electron multiplier and ultraviolet light.
• Short CES pulses (10 ns) generated high electron flux density (10^13–10^14 m^-2) for rapid ionization.
• A pulse valve system was employed to manage sample injection and vacuum requirements.

Main Results:

• The CES achieved rapid ionization, overcoming resolution limits in short drift tubes.
• Sample injection using the pulse valve reduced vacuum load and facilitated temporary molecular layering.
• Successful benzene measurements at ambient pressure demonstrated the system's potential for immediate analysis.

Conclusions:

• The developed CES and pulse valve system are technically viable for creating highly compact and portable TOF MS devices.
• This approach addresses key limitations in current mass spectrometry technology, paving the way for field-deployable instruments.
• The system enables immediate, on-site analysis, expanding the applications of TOF MS.