Routine Calibration of Cryogenic Thermometers in the Range 1.5–350K with an Accuracy up to the Millikelvin Level, and Measurement of Fixed Points in Sealed Cells with a Fully Automated and Self-Contained Modular Apparatus

Pavese, Franco; Malyshev, V. M.; Steur, P. P. M.; Ferri, D.; Giraudi, D.

doi:10.1007/978-1-4613-0373-2_211

Cited by 9 publications

(3 citation statements)

References 1 publication

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“…In our substrate we typically install between 3 to 5 working standards that are calibrated in a different apparatus 4 . The working standards are compared periodically with a set of four secondary standards that are traceable in the 1.5 K to 30 K range to standards maintained in a national metrological laboratory.…”

Section: Resultsmentioning

confidence: 99%

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Cryogenic Thermometer Calibration Facility at CERN

Balle

Casas

Thermeau

1998

Advances in Cryogenic Engineering

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A cryogenic thermometer calibration facility has been designed and is being commissioned in preparation for the very stringent requirements on the temperature control of the LHC superconducting magnets. The temperature is traceable in the 1.5 to 30 K range to standards maintained in a national metrological laboratory by using a set of RhodiumIron temperature sensors of metrological quality. The calibration facility is designed for calibrating simultaneously 60 industrial cryogenic thermometers in the 1.5 K to 300 K temperature range, a thermometer being a device that includes both a temperature sensor and the wires heat-intercept. The thermometers can be calibrated in good and degraded vacuum or immersed in the surrounding fluid and at different Joule self-heating conditions that match those imposed by signal conditioners used in large cryogenic machinery. The calibration facility can be operated in an automatic mode and all the control and safety routines are handled by a Programmable Logic Controller (PLC). LabVIEW ® is used both as the PLC operator interface and for configuring and reading the thermometric data sampled by the higher accuracy laboratory equipment. The isothermal support onto which the thermometers are mounted is thermally anchored through the wiring to a helium bath. The calibration procedure begins once the temperature of the support is stabilized. Measured data is presented and it is possible to infer that the absolute accuracy that can be obtained is better than ± 5 mK for the full temperature range.

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Section: Resultsmentioning

confidence: 99%

“…At present the CERN temperature standard is maintained by comparing a set of secondary and working RhFe temperature standards; the apparatus for this purpose has been described elsewhere 4 . A primary temperature standard consisting of a neon triple point sealed cell is used to perform periodical checks on the secondary standards.…”

Section: Introductionmentioning

confidence: 99%

Cryogenic Thermometer Calibration Facility at CERN

Balle

Casas

Thermeau

1998

Advances in Cryogenic Engineering

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“…There are two design approaches to develop a cryogenic temperature sensor calibration setup. One is based on cryocoolers which is very expensive below 15 K. The second one cited in [14] uses cryostat and liquid helium (LHe) with the facility of easy interchange of isothermal sections containing sensors. The second approach is custom built to fulfill the specific need of the user and there is no definite standard solution.…”

Section: Introductionmentioning

confidence: 99%

Development of an experimental variable temperature set-up for a temperature range from 2.2 K to 325 K for cost-effective temperature sensor calibration

Pal¹,

Kar²,

Mandal³

et al. 2017

Meas. Sci. Technol.

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A prototype of a variable temperature insert has been developed in-house as a cryogenic thermometer calibration facility. It was commissioned in fulfilment of the very stringent requirements of the temperature control of the cryogenic system. The calibration facility is designed for calibrating industrial cryogenic thermometers that include a temperature sensor and the wires heat-intercept in the 2.2 K–325 K temperature range. The isothermal section of the calibration block onto which the thermometers are mounted is weakly linked with the temperature control zone mounted with cooling capillary coil and cryogenic heater. The connecting wires of the thermometer are thermally anchored with the support of the temperature insert. The calibration procedure begins once the temperature of the support is stabilized. Homogeneity of the calibration block’s temperature is established both by simulation and by cross-comparison of two calibrated sensors. The absolute uncertainty present in temperature measurement is calculated and found comparable with the measured uncertainty at different temperature points. Measured data is presented in comparison to the standard thermometers at fixed points and it is possible to infer that the absolute accuracy achieved is better than ±0.5% of the reading in comparison to the fixed point temperature. The design and development of simpler, low cost equipment, and approach to analysis of the calibration results are discussed further in this paper, so that it can be easily devised by other researchers.

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