title: A fast differential paramagnetic O2-sensor.
abstract: A differential oxygen sensor using the paramagnetic principle in a pneumatic bridge configuration has been constructed and tested. The signal being picked up with a differential pressure transducer is generated in a measuring cell with a strong magnetic field being switched on and off with a frequency of 110 Hz. The output signal is a DC-voltage proportional to the O2 concentration difference between the two gases to be measured. A response time of 130 ms has been obtained. A special emphasis on the mechanical design was put to minimize the internal magneto-mechanical noise and to attenuate the external pressure and vibration interference. To eliminate the relatively strong temperature dependence of the paramagnetic effect a compensation circuit was designed as an integral part of the sensor. In performance investigations linearity, stability, noise, humidity and pressure effects as well as sensitivity for other gases were studied.
authors.affiliation: Datex Instrumentarium Corp., Helsinki, Finland.
authors.forename: P T
authors.initials: PT
authors.lastname: Meriläinen
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D006801:Humans; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D010100:Oxygen; D010101:Oxygen Consumption; D012121:Respiration, Artificial; D014160:Transducers, Pressure
chemical_list: D010100:Oxygen