Platinum-cobalt cryogenic RTD sensor
Platinum-cobalt cryogenic RTD sensors are designed for accurate temperature measurement at extremely low temperatures. Okazaki’s CERACOIL sensor is available as PtCo100 and PtCo1000 and can measure temperatures down to approximately 1.5 K (-271°C). It is designed for demanding cryogenic applications including liquid hydrogen (LH₂) storage and energy systems, aerospace, superconducting technologies, particle accelerators and medical equipment.
We also offer cryogenic coaxial MI cable assemblies.
Product summary
- Suitable for extreme cryogenic temperatures (as low as 1.5K)
- High precision and repeatability
- Excellent performance under vibration
- Two resistance options: Pt100 and Pt1000
- Ideal for critical applications like aerospace and medical industries
CERACOIL platinum-cobalt sensors by Okazaki
CERACOIL is a patented platinum-cobalt cryogenic resistance sensor developed by Okazaki. The sensor is available in PtCo100 and PtCo1000 versions.
Okazaki has been involved in the production of sensors for space equipment mounted on Japanese H-IIA/H-IIB spacecrafts. Furthermore Okazaki is authorized and registered on the European preferred part list (EPPL) for the European Space Agency (ESA).
The patented CERACOIL was developed by Okazaki and incorporates technology developed for various aerospace applications where accuracy in extreme conditions is essential. As such, CERACOIL sensors can be relied on for exceptional quality and high precision readings in most cryogenic applications.
The platinum cobalt sensor, CERACOIL, is available in two resistances, Pt100 and Pt1000.
Technical specifications of the CERACOIL platinum-cobalt cryogenic sensor
Okazaki’s platinum cobalt cryogenic sensor offers a number of important advantages:
- The tightly wound platinum resistance wires make these sensors suited to environments with high levels of vibration
- Excellent resistance value changes, even below 4K(-269°C).
- Superior repeatability
- Temperature measurement is feasible at exceptionally low temperatures (as low as 1.5K (-271°C))
| Nominal resistance | PtCo 100Ω / 1000Ω at 0°C |
| Measurement temperature range | 1.5 K to 373 K (-271°C to 100°C) |
| Tolerance | ±0.5 K at 4 K to 40 K / ±1 K at 273.15 K |
| Reproducibility* | ±20 mK (at 10 K) / ±10 mK (at 20 K) / ±33 mK (at 273.15 K) |
| Measuring current | 1 mA |
| Element dimensions | Ø1.4 x 12 mm |
| Length (L) | Pt100 25 mm / Pt1000 50 mm |
| Outside diameter (D) | Pt100 2.0 mm / Pt1000 3.5 mm |
*Reproducibility is the change amount from the initial value after 1000 heat cycles between 77 K and 300 K (-195°C to 26°C).
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Request a quotation for your cryogenic temperature sensor.
Where are platinum-cobalt cryogenic sensors used?
Platinum-cobalt cryogenic sensors are used where accurate temperature measurement is required at extremely low temperatures. Applications described by Kamet include particle accelerators, cryogenic gas storage, satellites and space telescopes, as well as aerospace, medical and superconducting systems.
Particle accelerators
Cryogenic sensors are a critical component in supercolliders (particle accelerators) where superconductivity has become a key technology. Cryogenics is primarily used to cool the superconducting components of particle accelerators. These cryogenic systems operate at temperatures from 4.2 K (-268°C) in supercritical, down to 2 K (-271°C) in superfluid.
Superconducting particle accelerators represent a field of industry that is set to expand with new conductors planned for Europe, Asia and America. It is therefore essential that cryogenic sensors continue to be developed and improved in order to meet these future demands.
Cryogenic thermoelectric generators and liquid hydrogen
CERACOIL platinum-cobalt sensors are used for temperature measurement in cryogenic thermoelectric generators (TEGs). These systems can utilise heat flows to support the vaporisation of cryogenic liquids, including liquid hydrogen (LH₂).
Liquid hydrogen has a boiling point of approximately 20 K (-253°C) at atmospheric pressure and requires reliable temperature measurement at extremely low temperatures. After vaporisation, the gaseous hydrogen can be supplied to applications such as fuel cells or hydrogen engines. With a measurement range starting at 1.5 K, CERACOIL is well suited to these demanding cryogenic applications.
Satellites and space telescopes
(Research) satellites and space telescopes increasingly include cryogenic technology in the form of cryocoolers to ensure their operation at optimal performance. As such, cryogenic sensors have become an important part of the ancillary instrumentation in these structures.
Why platinum cobalt sensors over silicon diodes?
Sometimes silicon diodes are used for temperature measurement in cryogenic applications. While these sensors have some advantages in terms of interchangeability and price, they also have distinct disadvantages. In comparison to platinum cobalt sensors, silicone diodes are:
- significantly less accurate
- strongly influenced by magnetic fields at temperatures below 40K(-233°C)
- tend to self-heat due to their relatively high power dissipation
In conclusion, where high accuracy is required, such as is the case for components in critical systems, then the cost of sensor failure can be considered higher than the cost of investing in a high quality cryogenic sensor, such as the CERACOIL.
PtCo 100Ω Temperature – Resistance Table
| Absolute temperature | Resistance | Absolute temperature | Resistance | Absolute temperature | Resistance | Absolute temperature | Resistance |
|---|---|---|---|---|---|---|---|
| K | Ω | K | Ω | K | Ω | K | Ω |
| 1.5 | 7.329 | 20.0 | 9.506 | 120.0 | 44.134 | 220.0 | 81.094 |
| 2.0 | 7.421 | 30.0 | 11.246 | 130.0 | 47.952 | 230.0 | 84.680 |
| 3.0 | 7.606 | 40.0 | 13.853 | 140.0 | 51.734 | 240.0 | 88.252 |
| 4.0 | 7.792 | 50.0 | 17.109 | 150.0 | 55.482 | 250.0 | 91.811 |
| 5.0 | 7.937 | 60.0 | 20.759 | 160.0 | 59.207 | 260.0 | 95.356 |
| 6.0 | 8.066 | 70.0 | 24.611 | 170.0 | 62.906 | 270.0 | 98.890 |
| 7.0 | 8.182 | 80.0 | 28.535 | 180.0 | 66.583 | 280.0 | 102.411 |
| 8.0 | 8.289 | 90.0 | 32.477 | 190.0 | 70.239 | 290.0 | 105.921 |
| 9.0 | 8.388 | 100.0 | 36.394 | 200.0 | 73.875 | 300.0 | 109.419 |
| 10.0 | 8.483 | 110.0 | 40.280 | 210.0 | 77.493 |
PtCo 1000Ω Temperature – Resistance Table
| Absolute temperature | Resistance | Absolute temperature | Resistance | Absolute temperature | Resistance | Absolute temperature | Resistance |
|---|---|---|---|---|---|---|---|
| K | Ω | K | Ω | K | Ω | K | Ω |
| 1.5 | 73.290 | 20.0 | 95.059 | 120.0 | 441.337 | 220.0 | 810.942 |
| 2.0 | 74.210 | 30.0 | 112.460 | 130.0 | 479.515 | 230.0 | 846.803 |
| 3.0 | 76.060 | 40.0 | 138.527 | 140.0 | 517.338 | 240.0 | 882.522 |
| 4.0 | 77.920 | 50.0 | 171.0889 | 150.0 | 554.820 | 250.0 | 918.106 |
| 5.0 | 79.370 | 60.0 | 207.587 | 160.0 | 592.068 | 260.0 | 953.562 |
| 6.0 | 80.660 | 70.0 | 246.107 | 170.0 | 629.065 | 270.0 | 988.895 |
| 7.0 | 81.820 | 80.0 | 285.346 | 180.0 | 665.831 | 280.0 | 1024.109 |
| 8.0 | 82.890 | 90.0 | 324.766 | 190.0 | 702.386 | 290.0 | 1059.206 |
| 9.0 | 83.880 | 100.0 | 363.939 | 200.0 | 738.747 | 300.0 | 1094.191 |
| 10.0 | 84.830 | 110.0 | 402.804 | 210.0 | 774.927 |