A calibration of gold iron thermocouples is given

Finnemore, D. K.

Ostenson, J. E.

Stromberg, T. F.

English

A calibration of gold iron thermocouples is given.</p

Finnemore, D.

Ostenson, J.

Stromberg, T.

Digital Repository @ Iowa State University (ISU)

IS-1046 IOWA STATE UNIVERSITY Au Fe vs Cu THERMOCOUPLES by D. K. Finnemore, J. E. Ostenson and T. F. Stromberg RESEARCH AND DEVELOPMENT REPORT U.S.A.E.C. ~ PHYSICAL SCIENCES READING RO\ ~ IS-1046 Physics (UC-34) TID 4500, October 1, 1964 UNITED STATES ATOMIC ENERGY COMMISSION Research and Development Report Au Fe vs Cu THERMOCOUPLES by D. K. Finnemore, J. E. Ostenson and T. F. Stromberg November, 1964 Ames Laboratory at Iowa State University of Science and Technology F. H. Spedding. Director Contract W-7405 eng-82 2 IS-1046 This report is distributed according to the category Physics (UC-34) as listed in TID 4500, October 1, 1964. r--------- LEGAL NOTICE----------. This report was prepared as an account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or representation, expressed or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this report. As used in the above, "person acting on behalf of the Commission" includes any employee or contractor of the Commission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee of such contractor prepares, disseminates, or provides access to, any information pursuant to his employment or contract with the Commission, or his employment with such contractor. Printed in USA. Price $ l. 00 Available from the Office of Technical Services U. S. Department of Commerce Washington 25, D. C. IS-1046 3 Au Fe vs Cu THERMOCOUPLES D. K. Finnemore~ J, E. Ostenson and T. F. Stromberg ABSTRACT A calibration of gold iron thermocouples is given. 1 Berman and Huntley have shown that Au doped with a few hundredths of a percent Fe makes a satisfactory thermocouple element at low temperatures. They find that a gold+ 0. 03 at. o/o iron~ silver normal thermocouple is reproducible to better than 0. 5% and has a sensitivity greater than 10 ~V /°K in the temperature range from 1 to 20°K. We have measured the thermoelectric voltage of Au 0. 07 at. % 1 Fe vs Cu and find results complementary to those of Berman. ):c The Au-Fe wire, prepared by Engelhard Industries, Inc.. is drawn into 0. 006 in. diam wire, annealed at 550°C for 12 h in a reducing atmosphere and then insulated with heavy formvar. For the second wire of the thermocouple we have chosen copper because high purity wires are readily available. For applications where thermal conduc-tivity must be low, silver normal would be a more appropriate second element. The voltages are measured with a Leeds and Northrup type K-3 potentiometer and a 0. 0006 JJA/mm Leeds and Northrup galvanometer. ' * Engelhard Industries, Inc .• Baker Platinum Division, 113 Astor St .• Newark 14, New Jersey. 4 Temperatures in the range from 4. 2 to 20°K are determined by the constant volume gas thermometer shown in Fig. 1. The entire 135 cc gas bulb is machined from high purity copper. Eight deeply recessed holes are cut in the top block to accommodate either germanium resistors or Au-Fe thermocouples. The copper rod which runs down the center of the bulb contains both the 2 cc vapor pressure bulb and a threaded hole for affixing other experiments. A special groove is cut in the main block for an astatically wound manganin heater. Another groove just above the heater provides an area for thermally connecting the electrical leads to the copper block before they go to the resistors or thermocouples. A shield which surrounds the gas bulb provides a thermal reservoir at a temperature approximately 0. l°K below the gas bulb temperature. All connections to the gas bulb are thermally connected to this shield. The vapor pressure line is a 0. 052 in. i. d. stainless steel capillary; the gas bulb line is a 0. 020 in. i. d. stainless steel capillary. A copper -constantan thermocouple is cemented to the gas bulb capillary at approximately 30o-K to assist in the calculation of the dead volume correction. With the assumption that the thermal conductivity of the capillary varies linearly with temperature, we calculate the maximum dead volume correction to be one part in 900. The filling pressure of 3 Torr/°K gives a maximum non-ideality 2 cor-rection of 0. Ol6°K. Thermomolecular corrections are determined from the calculations of Roberts and Sydoriak. 3 If we assume that He 4 has a saturated vapor pressure of 760. 00 Torr at 4. 215°K, then we measure the temperature of equilibrium hydrogen at a saturated vapor pressure 5 GERMANIUM RESISTOR CALIBRATION CRYOSTAT SS CAPILLARY TO MANOMETER GERMANIUM RESISTOR WELL VAPOR PRESSURE BULB ALL PARTS OF ELECTROLYTIC COPPER I I ct. SS CAPILLA'RY TO CONSTANT VOLUME MANOMETER GAS BULB I INCH 3/811 N .F. X I 1/411 DEEP Fig. l. Constant volume gas thermometer. 6 of 760. 00 Torr to be 20. 253 ± 0. 03°K. This value is within 0. 01 °K of that derived from the work of Moessen et al. • 4 but is 0. 025°K less than the value given by Hilsenrath et al. 5 As an additional check on 4 the thermometry we have measured the vapor pressure of He from 4. 2 to 5. 0°K and confirm the work of Berman and Swenson 6 (hence T-58) 7 to ± 0. 003°K. Results of the measurements (see Table I) are shown in Fig. 2. The striking feature of this curve is its linearity over a long tempera-ture range. It is this feature which strongly recommends Au-Fe thermocouples as a secondary thermometer. This linear behavior is shown even more clearly on Fig. 3. The sensitivity remains between 13. 5 and 14. 0 JJ.V joK all the way from 6 to 20°K. Even at 7 8°K the sensitivity has fallen only to 8 JJ.V /°K. For comparison we show in Fig. 3 the sensitivity for Au 0. 02 at. o/o Fe (absolute thermopower). 8 Note that the lower Fe concentration has a higher sensitivity at low temperatures but it falls off more rapidly at high temperatures. This reflects the fact that the magnetic ordering takes place at a lower temperature for the smaller Fe concentrations. Different voltage characteristics can be obtained by proper selection of the Fe concen-tration. These Au-Fe thermocouples provide a quick. easy and relia-ble method for determining temperatures to an accuracy of 0. 05°K in the range from 4. 2 to 20°K. Au 0.07 AT.% Fe vs Cu THERMOCOUPLE 1800 > 1600 ::l -~ 0 ~ ~ 1400 ...... (\J -> I -..... -> 1200 1000 800L-________ L_ ______ ~L-------~~------~~--------~--------~--------~--~ 0 10 20 30 40 50 60 -.1 T °K Fig. 2. Voltage plot for Au 0. 07 at. o/o Fe vs Cu thermocouple. The ice point is used as a reference temperature. 8 18 16 14 ~ 12 0 ' > :i. 10 >-..... > ..... 8 en z w 6 en 4 2 0 - Au 0.0 7 AT. 0/o Fe vs Cu -- Au0.02 AT. 0/o Fe ABSOLUTE THERMOPOWER8 0 20 30 40 50 60 70 80 Fig. 3. Sensitivity plots for Au 0. 07 at. o/o Fe vs Cu and Au 0. 02 at. o/o Fe absolute thermopower. REFERENCES 1R. Berman and D. J. Huntley, Cryogenics~ 70 (1963). 2J. E. Kilpatrick, W. E. Keller and E. F. Hammel, Phys. Rev. 97, 9 (1955). 3 T. R. Roberts and S. G. Sydoriak, Phys. Rev. 102, 304 (1956). 4 G. W. Moessen, J. G. Aston and R. G. Ascah, Temperature, Its Measurement and Control in Science and Industry, edited by C. M. 9 Herzfeld (Reinhold Publishing Corporation, New York, 1962), Vol. III, p. 91. 5 J. Hilsenrath, C. Beckett, W. Benedict, L. Fano, J. Masi, R. Nuttall, Y. Touloukian and H. Woolley, Tables of Thermodynamic and Transport Properties of Air, Argon, Carbon Dioxide, Carbon Monoside, Hydrogen, Nitrogen, Oxygen and Steam (Pergamon Press, Inc., New York, 1960). 6 R. Berman and C. A. Swenson, Phys. Rev. 95, 311 (1954). 7 F. G. Brickwedde, H. van Dijk, M. Durieux, J. R. Clement and J. K. Logan, J. Res. Natl. Bur. Standards 64A, 1 (1960). 8 D. K. C. MacDonald, W. B. Pearson and I. M. Templeton, Proc. Roy. Soc. A266, 161 (1962). 10 Table I Au-Fe vs Cu Thermocouple Calibration Temperature V(t)-V(273. l6°K) Temperature V(t)- V(273. l6°K) OK uv OK IJV 1. 925 1742. 1 5.643 1702. 1 2.295 17 38. 8 5.800 1700·. 6 2.295 1738.8 5.897 1699.0 2.456 1737.3 5.958 1698.4 2.666 17 35. l 5.958 1698.3 2.942 1732.3 5.959 1698.3 3.052 1731. l 6.029 1697.6 3. 271 1729.0 6. 311 1694. l 3. 271 1729.0 6.644 1689.9 3.325 1728.4 6.953 1686. 1 3.589 1725.6 7.065 1684.4 3.599 17 25. 5 7. 193 1683. l 3.599 1725. 6 7.374 1680.5 3.717 17 24. 1 7.461 1679.6 3.718 17 24. 1 7.588 1677.5 3.769 1723.6 7. 594 1677.6 3.820 17 23. 0 7.658 1677.0 3.820 17 23. 1 7.852 1674.3 3.883 1722.5 7.938 1673. 1 3.884 17 22. 5 8. 154 1670.4 3.920 17 22. 1 8. 176 1670.0 3.994 1721.3 8.266 1668.9 4.085 17 20. 4 8.355 1667.8 4.088 1720.4 8.391 1667.3 4.089 17 20. 4 8.494 1665.9 4.089 1720.4 8.564 1664.9 4.093 1720.2 8.629 1664.0 4. 156 1720.4 8.708 1663.0 4.292 17-18.0 8.803 1661. 8 4.542 1715. 1 8.852 1661. 0 4.764 17 12. 6 8.902 1660.3 5.048 1709. 4 8.963 1659.6 5.051 1709.4 9.060 1658.3 5. 195 1707.6 9. 146 1657.0 5.302 1706.4 9. 185 1656.5 11 Table I (Cont.) Temperature V(t)-V(273. l6°K) Temperature V(t)- V(27 3. l6°K) OK I-LV OK IJV 9.302 1655.0 14.373 1585.6 9.387 1654.0 14. 374 1585.6 9.393 1654.0 14.747 15 80. 3 9.447 1653.0 14.956 1577.2 9.540 1651. 9 14.958 1577:8 9.615 1650.9 15.298 1572.8 9.618 1650.9 15.505 1569.6 9.701 1649.7 15.843 1564.6 9.746 1649.2 15.847 1564.7 9.848 1647.7 15.874 1564.7 9.902 164 7. 1 16.533 1556. 1 9.969 1646. 1 17.322 1545.2 10.053 1644.9 17.808 1538.6 10. 113 1644.3 18.384 1530.5 10. 114 1644.3 18.732 1525.7 10. 189 1643.0 19.235 1518.9 10.277 1641. 9 19.240 1518.9 10.331 1641. 0 10.392 1640.4 10.559 1638.2 10.744 1635.4 64.00 1021.6 11. 014 1631.8 66. 18 1004.5 11. 229 1628.9 67.85 989.7 11. 232 1628.9 70. 19 970.4 11. 464 1625.7 72.22 953.9 74.60 934.8 11. 695 1622.5 77.48 913.6 11. 97 5 1618.5 12.486 1611.6 12.693 1608.8 12.956 1605. 1 13.206 160 l. 6 13. 517 1597.4 13.762 1593.9 14. 109 1589.2 14.360 1585.5 

Au Fe vs Cu thermocouples

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Au Fe vs Cu thermocouples

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