Mark Wadsworth

Miniature focal plane mass spectrometer with 1000-pixel modified-CCD detector array for direct ion measurement

A high performance, focal plane miniature mass spectrometer (MMS) of Mattauch–Herzog geometry with a CCD-based array detector for the direct and simultaneous measurements of different mass ions is described. Miniaturization (10cm×5cm×5cm,395g) was accomplished by using high-energy-product magnet material (Nd–B–Fe alloy) and a high permeability yoke material (V–Co–Fe Alloy) for the fabrication of the magnetic sector. The electrostatic sector was machined from a single piece of machinable ceramic (MACOR). All the components of the analyzer are mounted on a single plate, which facilitate their alignment and make the instrument rugged. The modified-CCD based ion detector array has 1000 elements (20μm×2mm) and was invented in our laboratory. The photosensitive part of the CCD was replaced with a metal-oxide-semiconductor (MOS) capacitor for ion detection. The ion sensing capacitor plates are connected to the CCD gates that are operated in the fill-and spill mode providing a gain in the charge domain for the si...

Subelectron readout noise focal plane arrays for space imaging

Readout noise levels of under 1 electron have long been a goal for the FPA community. In the quest to enhance the FPA sensitivity, various approaches have been attempted ranging from the exotic Photo-multiplier tubes, Image Intensifier tubes, Avalanche photo diodes, and now the on-chip avalanche charge amplification technologies from the CCD manufacturers. While these techniques reduce the readout noise, each offers a set of compromises that negatively affect the overall performance of the sensor in parameters such as power dissipation, dynamic range, uniformity or system complexity. In this work, we overview the benefits and tradeoffs of each approach, and introduce a new technique based on ImagerLabs’ exclusive HIT technology which promises sub-electron read noise and other benefits without the tradeoffs of the other noise reduction techniques.

The Impact of Astronomy Technologies on Chemical Analysis

The chemical sciences have been profoundly influenced by the development of advanced focal plane array detectors. The incorporation of existing technologies developed for infrared multiplexers has already had a positive effect on the fields of isotope ratio mass spectrometry and ion mobility spectrometry. Multiplexer based ion detectors have improved detection limits by several orders of magnitude over conventional Faraday cups while maintaining a high degree of stability.