Realization of the 1976 provisional 0. 5 K to 30 K temperature scale at the National Bureau of Standards. Final report

Technical Report · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6196498

Pfeiffer, E R; Kaeser, R S

The National Bureau of Standards presently disseminates a version of the 1976 Provisional 0.5 K to 30 K Temperature scale (EPT-76) which is maintained on two rhodium-iron resistance thermometers. Calibrations on the EPT-76 are made using an automated cryostat-regulation and data-acquisition system under the control of a dedicated laboratory minicomputer. Maintenance of the scale is periodically checked against realization of the superconducting transition points of NBS SRM 767 (which comprises 5 of the 11 defining reference points of the EPT-76). In addition, versions of the EPT-76 derived from the NBS 2-20 K Scale (maintained on germanium resistance thermometers) and from the NBS version of IPTS-68 (maintained on platinum resistance thermometers) have been realized and compared with the rhodium-iron based scale over their respective overlapping regions. From those checks and comparisons, and from similar data from other sources, it is concluded that the EPT-76 is non-unique by as much as 1 mK at several places over its 0.5 K to 30 K range. Thus, an uncertainty of + or - 1 mK has been assigned to the EPT-76 currently being disseminated by NBS. These are tolerable limits considering the provisional status of the scale.

• Research Organization: National Bureau of Standards, Washington, DC (USA)
• OSTI ID: 6196498
• Report Number(s): PB-83-143479
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CALIBRATION
CRYOGENICS
DATA ACQUISITION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
MEASURING INSTRUMENTS
PHYSICAL PROPERTIES
STANDARDS
SUPERCONDUCTIVITY
TEMPERATURE MEASUREMENT
THERMOMETERS