B.A Trisna , Suherlan , A. Achmadi , G. Zaid ● Temperature Metrology Subdivision

1. Construction and Characterization of Aluminum Fixed Point Cell for Standard in Thermocouple Calibration B.A Trisna, Suherlan, A. Achmadi, G. Zaid ● Temperature Metrology Subdivision Research Centre for Calibration, Instrumentation and Metrology (Puslit KIM-LIPI), Tangerang Selatan, Indonesia INTRODUCTION In this work, Puslit KIM-LIPI presents the development and characterization of an open type aluminum fixed point cell to be used as a standard in the calibration of noble metal thermocouple by fixed point method. The cell was verified by a direct comparison with primary Al cell manufacturer by Hart Scientific. The new method is expected to improve the Appendix C CMC claim for thermocouple calibration on Puslit KIM-LIPI CONSTRUCTION OF AL CELL Fig. 2 Immersion Profile of Primary and Secondary Al Cell The aluminium fixed point cell was constructed from ultra high purity (99.9999%) aluminum pellet that contained at a cell assembly. The aluminum pellet used to fill the crucible was supplied by Johnson Matthey Co, Canada. Cell cap, Ar inlet/ outlet, and quartz glass assembly were built in Puslit KIM-LIPI. Graphite crucible with 99.999% purity was used to maintain the purity of the fixed point material inside crucible. Outer quartz glass was sandblasted in order to minimize heat loss due to radiation. CONCLUSIONS The new Al FP cell we have described may improve the Appendix C CMC of Puslit KIM-LIPI. The total uncertainty with this new standard is 0.15 °C, much lower than the Appendix C CMC value of 0.39 °C at the same temperature. The secondary cell differs from the primary by 0.03 °C which is within the uncertainty of measurement as shown on Fig. 3. Fig. 3 Comparison of Primary and Secondary Al Fixed Point REFERENCES Fig. 1 Schematic Diagram of Secondary Al Fixed Point Cell for Thermocouple Calibration 1. Astrua, M, M. Battuello, and F. Girard, in On the Use of the Co–C Fixed Point for Calibration of Pt/Pd Thermocouples, Vol 32 (International Journal of Thermophysics, 2008) 2.Todd, A.D.W, ET all, in Cobalt–Carbon Eutectic Fixed Point for Contact Thermometry, Vol 32 (International Journal of Thermophysics, 2011) 3.Todd, A.D.W, ET all, in Palladium–Carbon Eutectic Fixed Point for Thermocouple Calibration, Vol 32 (International Journal of Thermophysics, 2011) 4.Edler, F and A.C Baratto, in Comparison Of Nickel–Carbon And Iron–Carbon Eutectic Fixed Point Cells For The Calibration Of Thermocouples, Metrologia 43, 501-507 (2006) 5.Edler, F and J. Hartmann, in Simultaneous Contact and Non-contact Measurements of the Melting Temperature of a Ni–C Fixed-Point Cell, Vol 28 (International Journal of Thermophysics, 2007) 6.Steur, P.P.M and R. Dematteis, in Production of a New Tin Cell at INRIM, Vol 32 (International Journal of Thermophysics, 2011) 7.Duris, S ET all, in Development of Fixed-Point Cells at the SMU, Vol 29 (International Journal of Thermophysics, 2008) 8.CCT Working Group 1, in Supplementary Information for the International Temperature Scale of 1990, BIPM, 177 pp., 1990 MEASUREMENTS The characterization of New KIM-LIPI aluminum fixed point cell was performed by comparing it with the established primary aluminum standard Al cell. The reproducibility was calculated from the standard deviation of three times realizations for each cell. the uncertainty due to heat flux was measured by considering the variation of emf over a length of 30mm from bottom of the thermometer well as shown on Fig. 2. The contribution of the thermocouple inhomogeneity was determined by evaluating the immersion profile from temperature distribution (fig. 2) over a distance of 150 mm in a primary Al fixed point cell. The inhomogeneity of the thermocouple was found to be 0.03 °C. Half of the maximum differences in emf measured at primary Al freezing point from three realizations were retrieved to estimate the uncertainty contributions caused by drift effect of thermocouple. ACKNOWLEDMENTS The Authors would like to thank Puslit KIM-LIPI for funding this work.