A radiation-hard, non-contact fluid sensor for radioisotope production applications
- Duke Univ. Medical Center, Durham, NC (United States)
It is often necessary to be able to detect the presence, or absence of fluids in tubing located in high gamma-ray or neutron flux areas. Non-contact methods are essential because direct electrode contact with the fluid has the potential for generating impurities. Optical sensing utilizing a light source and a photodetector is probably the most prevalent method used for non-contact fluid measurement. However, this method is not always suitable for use in a high radiation flux area because the phototransistor or photodiode used for light detection can be susceptible to radiation damage. The sensor described here detects changes in capacitance between two electrodes located on the outside of a length of non-conductive tubing. The sensing head consists of an AC bridge circuit constructed from miniature passive devices, thus making it immune to the effects of a high radiation environment. The readout electronics consist of a transformer coupled, 5 Khz oscillator that provides the excitation voltage, a differential amplifier followed by a band-pass filter to measure the bridge output, an active rectifier circuit to convert the bridge output to a DC voltage, and a comparator circuit that drives an LED indicator. The readout electronics can be remotely located away from the high radiation area. This sensor can be used for remote indication of target filling operations, as well as for fluid level and flow sensing in automated radiopharaceutical synthesis systems.
- OSTI ID:
- 199843
- Report Number(s):
- CONF-941129-; TRN: 95:005652-0345
- Resource Relation:
- Conference: 13. international conference on the application of accelerators in research and industry, Denton, TX (United States), 7-10 Nov 1994; Other Information: PBD: 1994; Related Information: Is Part Of Thirteenth international conference on the application of accelerators in research and industry; Duggan, J.L.; Morgan, I.L. [eds.]; PB: 201 p.
- Country of Publication:
- United States
- Language:
- English
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