Isotech has introduced the 935-14-154 Low Temperature Reference Probe, a new semi-standard platinum resistance thermometer designed for laboratory measurements from −196°C to 100°C
Developed particularly to complement the Model 526 Ultra-Low Dry Block Calibrator, the new probe provides a practical reference thermometer for laboratories working at very low temperatures, including cryogenic and cold-chain applications.

Designed for Low Temperature Dry Block Calibration
One of the key features of the 935-14-154 is its short 8 mm sensing element.
Temperature within a dry block is not perfectly uniform along the depth of the calibration well. A long sensing element can therefore extend across a larger axial temperature gradient and effectively average the temperature over that length.
By reducing the sensing length to just 8 mm, the 935-14-154 samples a much smaller region of the calibration volume, helping to reduce the influence of axial temperature gradients on the measurement.
The probe has a 4 mm diameter, 300 mm long stainless-steel sheath, allowing it to fit directly into the standard insert supplied with the Model 526 without requiring a specially machined insert.

From Liquid Nitrogen to 100 °C
With an operating range from −196 °C to 100 °C, the probe extends down to the boiling point of liquid nitrogen.
This makes it suitable for applications including low-temperature dry block calibration, cryogenic measurement, cold-chain and biobanking validation, and environmental chamber verification.
The probe uses a handmade, coil-wound Pt100 sensing element with four-wire connection, based on the established construction of Isotech’s 935-14 semi-standard thermometer range.
A spring cable relief is incorporated at the probe handle to provide additional support at the cable entry, particularly useful where the thermometer is regularly moved between dry blocks, liquid baths and dewars.
A Complete Low Temperature Calibration System
The 935-14-154 can be combined with the Model 526 Ultra-Low Dry Block Calibrator and an Isotech precision thermometer such as the milliK to provide a complete low-temperature comparison calibration system.

Isotech can also supply the probe with the required termination and calibration points, allowing it to be configured for the intended readout and application.
With a temperature range extending to liquid nitrogen temperatures, a compact sensing element and a design optimised for dry block use, the new 935-14-154 provides laboratories with a dedicated reference thermometer for demanding low-temperature calibration work.
Typical Applications
Key specifications: −196 °C to 100 °C temperature range, 8 mm sensing length, 4 mm diameter, 300 mm sheath length, coil-wound Pt100 sensor and four-wire connection.



