Despite many potential applications, miniature mass spectrometers have had limited adoption in the field due to the tradeoff between throughput and resolution that limits their performance relative to laboratory instruments. Recently, a solution to this tradeoff has been demonstrated by using spatially coded apertures in magnetic sector mass spectrometers, enabling throughput and signal-to-background improvements of greater than an order of magnitude with no loss of resolution. This paper describes a proof of concept demonstration of a cycloidal coded aperture miniature mass spectrometer (C-CAMMS) demonstrating use of spatially coded apertures in a cycloidal sector mass analyzer for the first time. C-CAMMS also incorporates a miniature carbon nanotube (CNT) field emission electron ionization source and a capacitive transimpedance amplifier (CTIA) ion array detector. Results confirm the cycloidal mass analyzer's compatibility with aperture coding. A >10× increase in throughput was achieved without loss of resolution compared with a single slit instrument. Several areas where additional improvement can be realized are identified. Graphical Abstract ᅟ.
Cycloidal sector
mass analyzers have, in principle, perfect focusing
due to perpendicularly oriented uniform electric and magnetic fields,
making them ideal candidates for incorporation of spatially coded
apertures. We have previously demonstrated a proof-of-concept cycloidal-coded
aperture miniature mass spectrometer (C-CAMMS) instrument and achieved
a greater than 10-fold increase in throughput without sacrificing
resolution, compared with a single slit instrument. However, artifacts
were observed in the reconstructed mass spectrum due to nonuniformity
in the electric field and misalignment of the detector and the ion
source with the mass analyzer focal plane. In this work, we modified
the mass analyzer design of the previous C-CAMMS instrument to improve
electric field uniformity, improve the alignment of the ion source
and the mass analyzer with the detector, and increase the depth-of-focus
to further facilitate alignment. A comparison of reconstructed spectra
of a mixture of dry air and toluene at different electric fields was
performed using the improved C-CAMMS prototype. A reduction in reconstruction
artifacts compared to our proof-of-concept C-CAMMS instrument highlights
the improved performance enabled by the design changes.
The rapid adoption of nanotechnology in fields as varied as semiconductors, energy, and medicine requires the continual improvement of nanopatterning tools. Lithography is central to this evolving nanotechnology landscape, but current production systems are subject to high costs, low throughput, or low resolution. Herein, we present a solution to these problems with the use of monolayer graphene in a graphene-insulator-semiconductor (GIS) electron emitter device for large-area electron lithography. Our GIS device displayed high emission efficiency (up to 13%) and transferred large patterns (500 × 500 μm) with high fidelity (<50% spread). The performance of our device demonstrates a feasible path to dramatic improvements in lithographic patterning systems, enabling continued progress in existing industries and opening opportunities in nanomanufacturing.
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