A magnetic design used to develop a Cycloidal Coded Aperture Miniature Mass Spectrometer (C-CAMMS)

Value Proposition

Field-able and miniature mass spectrometers have many potential applications in environmental monitoring, explosives trace detection, point of care medicine, and space exploration. However, miniaturization of mass spectrometers, and sector instruments in particular, leads to a throughput versus resolution tradeoff and poor performance relative to laboratory instruments, limiting their use in the field. Recently, the application of coded apertures to sector mass spectrometers has eliminated the tradeoff between throughput and resolution in sector mass spectrometry. However, imaging of the coded aperture pattern at the detector was relatively poor, due to the narrow electric sector and fringing fields.


Duke inventors have reported a permanent magnet assembly incorporated into cycloidal mass analyzers intended to be used to improving the imaging capabilities of miniaturized mass spectrometers. This invention takes full advantage of the unique focusing properties of the cycloidal mass analyzer by applying aperture coding to increase the instrument throughput without changing the system resolution. The novelty of the invention lies in the geometry of the magnetic assembly, which increases field uniformity and decreases size, weight, and cost. The cycloidal coded aperture mass spectrometer (C-CAMMS) also incorporates a miniature carbon nanotube (CNT) field emission electron ionization source and a capacitive transimpedance amplifier (CTIA) ion array detector. A working prototype has been developed.


  • The first application of coded apertures in a cycloidal mass analyzer
  • The novel geometry of the magnet assembly increases field uniformity and decreases size, weight, and cost compared to comparable assemblies
  • A >10x increase in throughput was achieved without loss of resolution compared to a single slit instrument