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The performance of manganin resistance gauges under high static pressure is evaluated. The accuracy of several interpolation- (or extrapolation-) based mathematical-models is compared. It is shown that if the gauges used at pressures below 1 GPa are calibrated at a given constant temperature and used at that temperature, the complete mathematical-model is unnecessary. However, a complete model for the variation of resistance with both pressure and temperature is required in the pressure range from 1 GPa up to 20 GPa, because the temperature changes due to compression or expansion of the pressure-transmitting medium can be quite pronounced. >

The high-static-pressure metrological characteristics of 1-GPa manganin resistance gauges are investigated. Nonlinearity is measured by means of a secondary standard-free piston gauge. A second-order mathematical-model is established, with an interpolation accuracy reaching 0.07%, as verified by calibration tests. The results obtained indicate that manganin resistance gauges exhibit very good stability, repeatability, and reproducibility. >

A new high temperature transducer is described. The transducer employs NiCr-NiSi thermocouple as a sensing-element and can directly measure flash surface temperature at 1230/spl deg/C under high pressure up to 400 MPa. It can be reused by abrading the hot-junction after it ablated. The response time constant is less than 1 /spl mu/s which was verified by theoretical calculation and by a calibrated test. This paper relates to the features of the transducer and the technology keys to the design of high-pressure-withstand poles, micrometer-order clearance between poles and high-resistance insulation. The theoretical analysis and calibration test are presented. The measurement results and curves of the inner-barrel surface temperature for a certain gun are given. >

A new type of high temperature withstanding high pressure transducer is described. The transducer uses Manganin wire as sensing-element and can measure pressure up to 250 MPa under condition of high temperature up to 200/spl deg/C for a long time. The expanded uncertainty in measurement of the transducer is less than 1.0% verified by calibration and practical use. This paper discusses the key technology issues, such as high pressure sealing and linearity correction under the temperature range from 0/spl deg/C to 200/spl deg/C, etc. The calibration test under high temperature condition is carried out against a free piston gauge having an uncertainty of 0.1%. Measured results in practical use on high-pressure cauldrons for growing man-made crystals are given.