Temperature calibrator 5900E

for RTD sensorsfor temperature sensorsfor thermometers

Key features

• Metal freeze-point cells manufactured with metal samples of ≥99.9999 % purity (commonly 99.99999 %).
• Complete ITS-90 fixed-point coverage from argon through copper, including TPW and gallium options.
• Long, stable plateaus (gallium: weeks; TPW: months under proper maintenance).
• Cells supplied with metal-sample purity assay; accredited intercomparisons available.

Product overview

• ITS-90 fixed-point metal freeze-point cells provide primary-standard realization close to theoretical freezing temperatures for high-accuracy temperature calibration.
• Fluke Calibration cells are fabricated in ultra-clean facilities using high-density graphite crucibles and sealed quartz or stainless steel envelopes evacuated and back-filled with high-purity argon; sealing is performed at the freezing point and argon pressure is measured and recorded for accurate pressure corrections.
• Traditional cells undergo melt-freeze curve testing and slope analysis; optional intercomparisons with Fluke reference cells are available.

Gallium cells

• 5943 Gallium Cell: stainless-steel envelope with high-purity gallium (99.99999 %) contained in a composite shell and filled with argon at one standard atmosphere at the melting point.
• Design accommodates ~3.1 % expansion on freezing with flexible, non-gas-permeable walls; no routine pumping/refilling required.
• Typical cell uncertainty: 0.1 mK (k=2); guaranteed maintenance of uncertainty < 0.1 mK for at least five years when used per instructions.
• Maintenance and automated realization with the 9230 Maintenance Apparatus yields melting plateaus up to eight days and supports weekly maintenance automation.

Water cells (TPW)

• Triple point of water cells overcome common ice-bath limitations (gradients, purity, repeatability) and are widely used for ITS-90 realizations near 0.01 °C.
• Fluke traditional-size TPW cells achieve published uncertainties of ±0.0001 °C in national-laboratory practice.
• Ice mantles can be formed using dry ice, LN2, or immersion freezers and can last up to two months when maintained in compatible Fluke baths (7012 or 7312).

Open metal cells

• Open quartz-glass metal cells use the same high-purity materials and manufacturing techniques as sealed cells but include a high-quality valve for precision pressure handling.
• Allow evacuation, inert-gas charging/purging, and regulated-pressure measurements to minimize uncertainties from pressure corrections—suitable for demanding temperature-versus-pressure applications and precision SPRT calibrations.
• Design features: extended height for valve access, pure quartz-wool insulation, high-purity graphite discs to reduce heat loss and optimize vertical gradients.
• Typical outside diameter: 50 mm; total heights vary by model (see specifications).

Specifications table (selected rows)
Specifications
Model | Fixed Point | Style | Assigned Value (°C) | Outside Diameter | Inside Diameter | Total Outside Cell Height | Depth‡ | Cell Uncertainty (mK, k=2) | Certification (mK, k=2)†
5900E | Mercury | Stainless Steel | −38.8344 | 31 mm | 8.2 mm | 470 mm | 200 mm | 0.2 | 0.25
5904 | Indium | Traditional Quartz Glass | 156.5985 | 48 mm | 8 mm | 285 mm | 195 mm | 0.7 | 0.7
5905 | Tin | Traditional Quartz Glass | 231.928 | 48 mm | 8 mm | 285 mm | 195 mm | 0.5 | 0.8
5906 | Zinc | Traditional Quartz Glass | 419.527 | 48 mm | 8 mm | 285 mm | 195 mm | 0.9 | 1.0
5907 | Aluminum | Traditional Quartz Glass | 660.323 | 48 mm | 8 mm | 285 mm | 195 mm | 1.3 | 1.8
5908 | Silver | Traditional Quartz Glass | 961.78 | 48 mm | 8 mm | 285 mm | 195 mm | 2.4 | 4.5
5909 | Copper | Traditional Quartz Glass | 1084.62 | 48 mm | 8 mm | 285 mm | 195 mm | 10.1 | 12.0
5924 | Indium | Open Quartz Glass | 156.5985 | 50 mm | 8 mm | 596 mm | 195 mm | 0.7 | 0.7
5925 | Tin | Open Quartz Glass | 231.928 | 50 mm | 8 mm | 596 mm | 195 mm | 0.5 | 0.8
5926 | Zinc | Open Quartz Glass | 419.527 | 50 mm | 8 mm | 596 mm | 195 mm | 0.9 | 1.0
5927A-L | Aluminum | Open Quartz Glass (long) | 660.323 | 50 mm | 8 mm | 696 mm | 195 mm | 1.3 | 1.8
5927A-S | Aluminum | Open Quartz Glass (short) | 660.323 | 50 mm | 8 mm | 596 mm | 195 mm | 1.3 | 1.8
5928 | Silver | Open Quartz Glass | 961.78 | 50 mm | 8 mm | 696 mm | 195 mm | 2.4 | 4.5
5929 | Copper | Open Quartz Glass | 1084.62 | 50 mm | 8 mm | 696 mm | 195 mm | 10 | 12.0
5943 | Gallium | Stainless Steel | 29.7646 | 38.1 mm | 8.2 mm | 250 mm | 168 mm | 0.1 | 0.1
† Certification uncertainty values may vary slightly from those listed here. ‡ Depth is measured from the bottom of the thermometer well to the top of the pure reference material.

Technical specifications

• Family: ITS-90 fixed-point metal freeze-point cells covering argon through copper.
• Typical metal sample purity: ≥99.9999 % (six 9s), often 99.99999 % (seven 9s).
• Cell styles: sealed stainless steel, traditional quartz glass sealed, open quartz glass (long/short variants), and metal-cased gallium.
• Representative assigned ITS-90 values: Mercury −38.8344 °C; Indium 156.5985 °C; Tin 231.928 °C; Zinc 419.527 °C; Aluminum 660.323 °C; Silver 961.78 °C; Copper 1084.62 °C; Gallium 29.7646 °C.
• Typical outside diameter: 31–50 mm; inside diameter ~8–8.2 mm.
• Total outside cell height: traditional cells ~285–470 mm; open/long variants up to ~696 mm; silver/copper sealed cells may be ~700 mm tall.
• Depth (thermometer well to reference): example values 168–200 mm depending on model.
• Cell uncertainty examples (k=2): as low as 0.1 mK (gallium) to 12.0 mK (copper) depending on fixed point and model.
• Supplied with metal-sample purity assay; traditional cells undergo melt-freeze curves and slope analysis; optional intercomparisons available.