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Thermodynamic Quantities

Resistance Thermometry

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Technical Contacts:
Weston L. Tew (0.65K to 84 K)
Tel: 301-975-4811
E-mail: weston.tew@nist.gov

Michal J. Chojnacky (83 K to 962 ºC)
Tel: 301-975-4821
E-mail: michalc@nist.gov


Please contact the technical staff before shipping instruments or standards to the address listed below.

Mailing Address:
National Institute of Standards and Technology
100 Bureau Drive, Stop 8363
Gaithersburg, MD 20899-8363

Service ID
Number
Description of Services Fee ($)
33010C Capsule SPRT (13.8 K to 30 ºC) e-H2 to Ga 10021
33020C Capsule SPRT (13.8 K to 157 ºC) e-H2 to In 10430
33030C Capsule SPRT (13.8 K to 232 ºC) e-H2 to Sn 10839
33031C Capsule SPRT (24.5 K to 30 ºC) Ne to Ga 7451
33032C Capsule SPRT (24.5 K to 157 ºC) Ne to In 7859
33033C Capsule SPRT (24.5 K to 232 ºC) Ne to Sn 8270
33040C Capsule SPRT (54 K to 30 ºC) O2 to Ga 6460
33050C Capsule SPRT (54 K to 157 ºC) O2 to In 6869
33060S Capsule SPRT (54 K to 232 ºC) O2 to Sn 7278
33065S Capsule SPRT (83 K to 0.01 ºC) Ar to TPW At Cost
33070C Capsule SPRT (83 K to 30 ºC) Ar to Ga 3507
33080C Capsule SPRT (83 K to 157 ºC) Ar to In 3711
33090C Capsule SPRT (83 K to 232 ºC) Ar to Sn 4068
33100C Capsule SPRT (0 ºC to 30 ºC) TPW to Ga 1419
33110C Capsule SPRT (0 ºC to 157 ºC) TPW to In 2084
33120C Capsule SPRT (0 ºC to 232 ºC) TPW to Sn 2677
33130C Capsule SPRT (234 K to 30 ºC) Hg to Ga 2687
33140C Rhodium-Iron or Platinum-Cobalt Resistance Thermometers (0.65 K to 24.6 K) 11759
33141C Rhodium-Iron or or Platinum-Cobalt Resistance Thermometers (0.65 K to 83.8 K) 14077
33142C n-Type Germanium Resistance Thermometers (0.65 K to 24.6 K) 11325
33150C Long Stem SPRT (83 K to 0 ºC) Ar to TPW 2811
33160C Long Stem SPRT (83 K to 30 ºC) Ar to Ga 3220
33170C Long Stem SPRT (83 K to 157 ºC) Ar to In 3414
33180C Long Stem SPRT (83 K to 232 ºC) Ar to Sn 3741
33190C Long Stem SPRT (83 K to 420 ºC) Ar to Zn 4304
33200C Long Stem SPRT (83 K to 661 ºC) Ar to Al 5501
33210C Long Stem SPRT (234 K to 30 ºC) Hg to Ga 2380
33220C Long Stem SPRT (234 K to 157 ºC) Hg to In 3096
33230C Long Stem SPRT (234 K to 232 ºC) Hg to Sn 3455
33240C Long Stem SPRT (234 K to 420 ºC) Hg to Zn 3894
33250C Long Stem SPRT (234 K to 661 ºC) Hg to Al 4529
33260C Long Stem SPRT (0 ºC to 30 ºC) TPW to Ga 1122
33270C Long Stem SPRT (0 ºC to 157 ºC) TPW to In 1745
33280C Long Stem SPRT (0 ºC to 232 ºC) TPW to Sn 2359
33290C Long Stem SPRT (0 ºC to 420 ºC) TPW to Zn 2819
33300C Long Stem SPRT (0 ºC to 661 ºC) TPW to Al 3433
33310C Long Stem SPRT (0 ºC to 962 ºC) TPW to Ag 6788
33330C Additional Copy of Table from Results of 33010C-33310C at a Later Date 242
33340C Minimum Charge for Unsuitable Thermometer 1060
33350S Special Tests of Resistance Thermometers At Cost
33355S Special Tests of Cryogenic Resistance Thermometers At Cost
33360S Special Tests of Thermometric Fixed-Point Devices At Cost
33370M Measurement Assurance Program for Temperature 83 K to 420 ºC (Ar to Zn) 12791
33380M Measurement Assurance Program for Temperature 83 K to 661 ºC (AR to Al) 16289


Fees are subject to change without notice.

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Resistance Thermometers (33010C-33310C)

NIST provides calibration services for standard platinum resistance thermometers (SPRTs) from 13.8 K to 1235 K. Both long-stem and capsule-type SPRTs are calibrated, providing direct access to the International Temperature Scale of 1990 (ITS-90). There are eleven temperature subranges over which an SPRT may be calibrated according to the ITS-90 definitions. From 13.8 K to 83.8 K, SPRT calibrations are performed by comparison with a set of NIST reference thermometers. From 83.8 K to 962 °C, calibrations are performed using the ITS-90 defining fixed points as described in NIST Technical Note 1265. Expanded uncertainties, as described in NISTIR 5319, for SPRT calibrations are given in Table 6.3. The comparison calibration of rhodium-iron resistance thermometers (RIRTs) in the temperature range from 0.65 K to 26 K, using the NIST-maintained ITS-90, is based on a set of reference capsule-type RIRTs. The expanded uncertainty of those calibrations is given in Table 6.4. Extended range RIRT calibrations, for temperatures greater than 26 K and up to 83.8 K, are accomplished by comparison with reference capsule SPRTs in the range 26 K to 83.8 K.

Table 6.3. Maximum Expanded Uncertainties of SPRTs at NIST

Temperature Subrange
(K)
Maximum Expanded Uncertainty
(mK)
13.8033 to 273.16 0.54a
24.5561 to 273.16 0.40a
54.3584 to 273.16 0.29a
83.8058 to 273.16 0.40
234.3156 to 302.9146 0.23
273.15 to 302.9146 0.07
273.15 to 429.7485 0.36
273.15 to 505.078 0.48
273.15 to 692.677 0.59
273.15 to 933.473 0.82
273.15 to 1234.93 1.95

a The uncertainties used at the Ar, Hg, and H2O triple points are based on the fixed-point realization.


Table 6.4.
NIST Expanded Uncertainties for Comparison Measurements of RIRTs

Range
(K)
Expanded Uncertainty
(mK)
0.65 to 2.0 0.5
2.0 to 5.0 0.08
5.0 to 8.8 0.17
8.8 to 13.8 0.21
13.8 to 17.0 0.34
17.0 to 20.3 0.18
20.3 to 24.5561 0.24
24.5561 to 54.3584 0.27
54.3584 to 83.8058 0.22

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To qualify for testing, either long-stem or capsule SPRTs must meet two conditions. They must meet the ITS-90 criteria of W (Hg) < 0.844 235 or W (Ga) > 1.118 07, and for use above 660 °C the criterion of W (Ag) > 4.2844. Second, they must be compatible with the NIST calibration equipment. It is important that, insofar as possible, resistance thermometers be protected from any mechanical shock that could alter their calibration. For shipment, the thermometer should be softly supported within a case but not be free to rattle. This necessitates the use of packing material that does not become compacted. The thermometer case should be softly packed inside a shipping container. The shipping container must be sufficiently rigid and strong that it will not appreciably deform under the treatment usually given by common carriers. Styrofoam is not sufficiently rigid to be used as an outside container. Similarly, mailing tubes are unacceptable. Thermometers will not be returned in containers that are obviously unsuitable, such as those closed by nailing. Suitable containers will be provided when a thermometer shipping container is not satisfactory for re-use.

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Special Tests of Resistance Thermometers and Special Tests of Thermometric Fixed-Point Devices (33350S and 33360S)

Special tests (e.g., certification, prototype testing) of various resistance thermometers and thermometric fixed-point devices may be made by prior arrangement with the specified technical contacts. Fixed-point cells may be sent to NIST for certification by the method of direct comparison with the applicable NIST laboratory standard fixed-point cell.

Special Tests of Cryogenic Resistance Thermometers (33355S)

Special tests (e.g., calibration, prototype testing) of various cryogenic resistance thermometers may be made by prior arrangement with the specified technical contact. Cryogenic resistance thermometers may be calibrated over the temperature range from 0.65 K to 84 K.

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Measurement Assurance Program for Temperature (33370M and 33380M)

The purpose of this Measurement Assurance Program (MAP) is to assure the accuracy of the calibration of temperature standards (83 K to either 420 °C or 661 °C) conducted by participating laboratories when using platinum resistance thermometry. Other temperature ranges are available upon request.

The MAP transport standard consists of sets of three commercial SPRTs packaged in a special shock-proof shipping container (mechanical shock may shift calibration values). These SPRTs are used to assess both the reproducibility and the uncertainty of calibrations performed by the participating laboratory.

MAP participants should use the techniques described in NIST Technical Note 1265 and ITS-90 fixed-point cells, or use an SPRT previously calibrated by NIST. In order to achieve high accuracy, SPRTs used as standards should be either metal sheathed or of the matte-finish glass-sheathed type to avoid systematic errors arising from light-pipe effects in the glass sheath. The participant must have a triple point of water cell and an appropriate resistance bridge.

NIST provides worksheets on which the participant records data. The participant calculates the thermometer constants from experimental data, records them, and prepares tables of either resistance ratio or resistance versus temperature. These completed worksheets and the participant's calibration reports are sent to NIST with the return of the MAP SPRTs.

The SPRTs are recalibrated upon return to NIST and the participant's data are compared with NIST's calibration results. NIST provides a plot of the participating laboratory's temperature deviation from NIST values and a written analysis of the data, including any pertinent observations. In a typical MAP transfer, the participant makes measurements over a period of 1 to 2 months. A typical turnaround time from the date NIST receives the participant's data until a test report is sent to the participant is 4 to 6 weeks. Former participants in the MAP have had expanded uncertainties that ranged from about 1 mK to several tens of millikelvins.

No rigid recommendations can be given concerning how often a participant should utilize the temperature MAP service. Experience has indicated that when temperature measurements are in a state of statistical control, as evidenced by in-house check standards and control charts used to monitor the measurement process, the participant should be able to go at least 3 years between transfers from NIST without significantly degrading the confidence in the correctness of the measurements.

Among other NIST Services for Temperature Calibration Laboratories, NIST provides Standard Reference Materials for use as defining fixed points of the ITS-90 and as secondary reference points.

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References-Resistance Thermometry

NIST Certification of ITS-90 Fixed-Point Cells From 83.8058 K to 1234.93 K: Methods and Uncertainties, G. F. Strouse, TEMPMEKO, (Jan. 2005).

Assessment of Uncertainties of Calibration of Resistance Thermometers at the National Institute of Standards and Technology, G. F. Strouse and W. L. Tew, Natl. Inst. Stand. Technol. NISTIR 5319, 16 (1994).

NIST Measurement Assurance of SPRT Calibrations on the ITS-90: A Quantitative Approach, Session 1-D, G. F. Strouse and B. W. Mangum, Proc. Meas. Sci. Conf., Anaheim, CA (Jan.1993).

NIST Implementation and Realization of the ITS-90 Over the Range 83 K to 1235 K. Reproducibility, Stability, and Uncertainties, G. F. Strouse, Temperature. Its Measurement and Control in Science and Industry, J. F. Schooley, Ed., 6, 169-174, Amer. Inst. Phys., New York, NY (1992).

Realization of the ITS-90 Below 83.8 K at the National Institute of Standards and Technology, E. R. Pfeiffer, Temperature. Its Measurement and Control in Science and Industry, J. F. Schooley, Ed., 6, 155-160, Amer. Inst. Phys., New York, NY (1992).

The International Temperature Scale of 1990 (ITS-90), H. Preston-Thomas, Metrologia 27, 3-10 (1990); Metrologia 27, 107 (1990).

NBS Measurement Services: Platinum Resistance Thermometer Calibrations, B. W. Mangum, Natl. Bur. Stand. (U.S.), Spec. Publ. 250-22 (1988).

Reproducibility of Some Triple Point of Water Cells, G. T. Furukawa and W. R. Bigge, Temperature, Its Measurement and Control in Science and Industry 5, 291, Amer. Inst. Phys., New York, NY (1982).

Standard Reference Materials: Application of Some Metal SRM's as Thermometric Fixed Points, G. T. Furukawa, J. L. Riddle, W. R. Bigge, and E. R. Pfeiffer, Natl. Bur. Stand. (U.S.), Spec. Publ. 260-77 (Aug. 1982).

A Measurement Assurance Program-Thermometer Calibration, G. T. Furukawa and W. R. Bigge, in Natl. Conference on Testing Laboratory Performance, Evaluation, and Accreditation, Natl. Bur. Stand. (U.S.), Spec. Publ. 591, 137 (Aug. 1980).

Determination of the Triple-Point Temperatures of Gallium, B. W. Mangum and D. D. Thornton, Metrologia 15, 201-215 (1979).

Platinum Resistance Thermometry, J. L. Riddle, G. T. Furukawa, and H. H. Plumb, Natl. Bur. Stand. (U.S.), Monogr. 126 (Apr. 1973).

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Program questions: Calibrations
Phone: 301-975-2200, Fax: 301-975-2950
>NIST, 100 Bureau Drive , Stop 8363, Gaithersburg , MD 20899-8363