5901 Triple Point of Water Cells

Overview

5901 Triple Point of Water Cells are ITS-90 fixed-point water cells provided for high-precision temperature realization and thermometer calibration at the triple point of water. Reported reproducibility is 0.00002 °C to 0.00005 °C and expanded uncertainty (k=2) is < 0.0001 °C to < 0.0002 °C. Isotopic composition specifications are provided relative to VSMOW: d18O values of ± 1.5 ‰ (± 0.15 %) or ± 3 ‰ and dD values of ± 10 ‰ (± 1 %) or ± 20 ‰; the listed effect of deviation from VSMOW on the realized temperature is ± 7 µK or ± 14 µK. Water source is listed as Ocean. These cells are intended for metrology and calibration laboratories performing ITS-90 realizations and high-accuracy thermometer calibrations where sub-millikelvin reproducibility and sub-0.0002 °C expanded uncertainty are required. Choice between variants is driven by required uncertainty and isotopic purity: the product data gives two uncertainty tiers and corresponding isotopic tolerances with quantified µK effects on the realized triple-point temperature. Practical selection also depends on mechanical compatibility with thermometer wells and enclosures: cells are supplied in multiple geometries and construction materials (Borosilicate Glass and Fused Silica (Quartz)) with available dimensions including 50 mm OD × 12 mm ID × 450 mm long; 60 mm OD × 13.6 mm ID × 420 mm long; 60 mm OD × 14.4 mm ID × 420 mm long; 60 mm OD × 12 mm ID × 420 mm long; and 30 mm OD × 8 mm ID × 180 mm long, and immersion depths of 265 mm or 118 mm. Select the geometry and immersion depth that match the calibration bath or triple-point cell enclosure and the probe diameter to ensure proper thermal contact and immersion.