Investigations of Solid-State Detectors for Time-of-Flight Mass Spectrometry, 15-9199

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Principal Investigators
Martin P. Wüest
Scott E. Weidner

Inclusive Dates: 07/01/2000 - Current

Background - SwRI has participated in recent years in the design and development of several mass spectrometers. Typical time-of-flight mass spectrometers for space flight most often include an electrostatic analyzer for energy per charge analysis and a time-of-flight section for velocity or mass determination. The ions are usually detected with microchannel plates. The addition of a solid-state detector to determine the residual energy of the ion allows the unambiguous determination of mass, charge, and energy independently, instead of obtaining just ratios of energy/charge or mass/charge. To resolve ions according to their charge state becomes important in determining the isotopic composition and charge state of the solar wind, or in quantifying minor ions in the Earth's magnetosphere. SwRI has no experience in solid-state detectors for space applications, and this internal research is directed toward providing this experience.

Approach - To gain experience with solid-state detectors for space flight mass spectrometry, the research team will test a commercially available solid-state detector in the SwRI ion calibration facility. In addition, the team will develop a front-end, space-qualifiable electronics board to read out the weak signals. To obtain an energy threshold as low as possible, a very low noise electronics board is required. Finally, the team will resolve some system design issues involved with operating a solid-state detector on a 30-kilovolt floating power supply.

Accomplishments - The team, which is only a short time into the project, has not yet achieved major accomplishments. A passivated, implanted, planar silicon detector has been ordered. Work has been underway to better define the requirements on the analog front-end electronics, and a preliminary design has been produced. Further, initial studies favor the concept that all signal-processing electronics is floating on the 30-kilovolt power supply.

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