With the UK’s record breaking hot weather continuing, we thought you might like to know that Lake Shore Cryotronics offer four types of sensor for temperature measurement:
A diode temperature sensor is the general name for a class of semiconductor temperature sensors. They are based on the temperature dependence of the forward voltage drop across a p-n junction. The voltage change with temperature depends on the material. The most common is Silicon, but Gallium Arsenide (GaAs) and Gallium Aluminium Arsenide (GaAlAs) are also used.
These sensors are based on the change of resistance with temperature, and can be classified as positive temperature coefficient (PTC) or negative temperature coefficient (NTC). Platinum RTDs are the best example of PTC resistance sensors.
Capacitors are also used for low temperatures, but usually not for temperature measurement. Capacitance temperature sensors have the advantage of being insensitive to magnetic fields, but they commonly experience calibration shifts after thermal cycling.
Thermocouples are only useful where differential temperature measurements or low mass are the main consideration. They must be calibrated in-situ as the entire length of the wire contributes to the output voltage if it traverses a temperature gradient.
Each type sensor has its own particular advantages in terms of temperature range and response, as well as design features and drawbacks, so Elliot Scientific recommends contacting us to discuss your application and its requirements.
Lake Shore also do some nice instruments to go with their sensors!
Data is currently available online for sensors shipped since the beginning of 2016, so if an existing CD is lost or damaged, the calibration data can be quickly downloaded providing you have the serial number of the relevant sensor on hand. Alternatively, contact Lake Shore Service for archived curves.
Lake Shore space-qualified sensors were on the hugely successful Cassini Huygens mission to Saturn that ended earlier this month.
Nearly twenty years of gathering temperature information in an extreme environment is a good advert for their sensors, and Elliot Scientific often supplies them to the aerospace industry and space scientists in the UK and Ireland.
Please contact us for more information.
Lake Shore offers four types of sensor for cryogenic temperature measurement based on voltage (diodes) or resistance. Each has its own advantages and disadvantages, and these can be easily seen at-a-glance via our new Cryogenic Temperature Sensors page.
For example: Of the three most common NTC resistor materials, sputter-deposited zirconium oxy-nitride aka Cernox™ – the others being Germanium and Ruthenium Oxide (Rox™) – is the most versatile. Cernox™ thin film resistors are only manufactured by Lake Shore Cryotronics, and incorporated into robust sensor packages.
Cernox™ works over a broad temperature range, does not follow a standard curve, has sensitivity below 1 K, and is highly resistant to ionising radiation and magnetic field-induced errors. These features can be instantly seen on the page via our colourful graphics:
|♨||0.1 to 420||⌒||✘||❆||✔||☢||✔||⋐||★★★ (1 K +)|
In all, nine different temperature sensor materials are detailed and an informative datasheet is available to download. However, Elliot Scientific still recommends contacting us for expert advice on sensor choice for your application.
The newly launched Lake Shore Model 224 temperature monitor offers precision measurement in a wide range of cryogenic and higher-temperature applications with the ability to easily monitor up to 12 sensor channels.
Available for delivery from September, it provides better measurement performance in applications where researchers need to ensure accuracy and precision in their low cryogenic temperature monitoring. Used with Lake Shore’s Cernox™ sensors, the Model 224 enables reliable and repeatable temperature measurement over a broad range and as low as 300 mK.
Cernox thin-film RTD sensors offer high sensitivity and low magnetic field-induced errors at cryogenic temperatures. The Model 224 has been optimised for use with these well-respected thermometers, and features many of the same advanced capabilities of Lake Shore Model 336 temperature controller, including its proven high-precision input circuitry.
In addition to Cernox, the Model 224 supports other NTC RTDs, PTC RTDs such as platinum sensors, and diodes such as the Lake Shore DT-670 Series. In cryogenic applications, the monitor is an ideal addition to any university or commercial low-temperature research lab requiring measurement flexibility using multiple sensors and sensor types.
Used with silicon diodes, it provides accurate measurements in cryo-cooler and cryo-gas production applications from 1.4 K to above room temperature. Connected to PTC RTDs (platinum and rhodium-iron sensors), the Model 224 works well in cryogenic applications at liquid nitrogen temperatures.