Engineering topics
Publications and source records attributed to Plews, G. S..
Nonclamping micrometer measures small strains. Electronic dilatometer measures minute dimensional changes caused by moisture absorption in graphite/ epoxy composites. Instrument handles sample 6 inches (15 cm) long and has strain resolution of 0.1 micro-inch/inch (0.1 micron/meter). Possible to predict humidity-induced dimensional changes in items constructed of sample material.
It is shown that a substantial reduction in internal noise generated by the photodiode and the preamplifier can be produced by a modest cooling of the components and by optimization of preamplifier design. With this reduction the silicon detectors can, in the SNR range of 5 or greater, produce better performance than photon-noise-limited photomultipliers. The circuit noise and frequency response model suggested by Goranson and Skipper (1974) is expanded to include the effects of frequency dependent FET voltage noise and FET load resistance noise. The modeling of the photodiode and preamplifier is described and the noise characteristics of a 0.01 Hz to 100 kHz bandwidth detector/amplifier channel are evaluated.