A parallel miniature cylindrical ion trap array

Area of Science:

• Analytical Chemistry
• Instrument Development
• Physical Chemistry

Background:

• Miniature mass spectrometers offer portability and low power but often have limited ion capacity.
• Cylindrical ion traps (CITs) are suitable for miniaturization but face challenges in sensitivity and throughput.
• Scaling up ion trap arrays is a potential strategy to enhance performance.

Purpose of the Study:

• To develop and characterize a novel mass spectrometer array composed of multiple cylindrical ion traps (CITs).
• To evaluate the performance of a multi-CIT array in terms of ion capacity, resolution, and sensitivity.
• To demonstrate the applicability of the multi-CIT array for process gas monitoring.

Main Methods:

• Fabrication of a four-element array of CITs with an inner radius of 2.5 mm, operated in parallel.
• Comparison of signal intensity between two-element and four-element CIT arrays.
• Mass analysis of m-dichlorobenzene to determine resolution.
• Detection of trace krypton in argon for process gas monitoring.
• Preliminary testing of a ten-element CIT array with 1.5 mm inner radius.

Main Results:

• The four-element CIT array demonstrated increased ion capacity compared to smaller arrays.
• Resolution for m-dichlorobenzene was approximately 180 (FWHM) without significant loss due to array configuration.
• Successful detection of 5 x 10(-9) Torr partial pressure of krypton in argon with a signal-to-noise ratio of ~30.
• A preliminary spectrum from a 10-CIT array was acquired, indicating scalability.

Conclusions:

• The multi-CIT array design effectively increases ion capacity while retaining the benefits of miniature ion traps.
• The developed mass spectrometer array shows promise for sensitive and reliable process gas monitoring.
• Further development with larger arrays and smaller trap dimensions is feasible and warrants investigation.