Silicon diodes are easily the most common temperature sensors used in cryogenic applications. They offer good sensitivity and a wide range of operation compared to other devices. Further, they have excellent interchangeability and stability.
The S900 is offered in three packages to fit a wide range of applications:
Temperature Range: 1.5 to 400K.
Marking: Inpidual serial number on the top of the package.
Mass: 1.1g excluding leads.
Construction: Bobbin Material is gold plated oxygen free hard copper. Sensor bonding is Stycast® epoxy.
Leads: 36”, 36AWG Phosphor-Bronze. Four-lead color coded cryogenic ribbon cable. Insulation is heavy Formvar® . Strain relief is Teflon®.
Mounting: 4-40 brass machine screw. A thin layer of Apiezon® N grease is recommended.
Temperature range: 1.5 to 400K.
Mass: 37mg
Thermal response time: <10mS at 4.2K, 100mS at 77K and 200mS at 305K.
Construction: Package material is gold plated OHFC copper on an Alumina substrate.
Leads: 3”, 37 AWG copper with Polyimide insulation. Positive connection is red and negative is black. Lead attach is 60/40 solder.
Mounting: Varnish, epoxy or clamp to a clean flat surface. Thermally anchor copper leads.
Temperature Range: 1.4 to 500K
Mass: 32mg
Thermal response time: <10mS at 4.2K, 100mS at 77K and 200mS at 305K.
Construction: Package material is Alumina with gold plated OHFC copper end caps. Leads are 3”, 37 AWG copper with Polyimide insulation.
Mounting: Sensor body must be electrically insulated from mounting surface. Attach using varnish or epoxy. Thermally anchor the copper leads.
Features
Good sensitivity over the temperature range from 1.4K to 400K (500K in the CP package). High sensitivity in the range from 20K to 1.4K.
Conforms to the standard S900 calibration curve with high accuracy, giving excellent interchangeability.
Available in two tolerance grades. Accuracy can be further improved using Cryo-con's CalGen® software.
Available in a variety of packages.
High repeatability and stability. Minimum long term drift.
Fabricated with non-magnetic materials.
Applications
Wide temperature range measurements outside of a magnetic field.
Cryocoolers and cryogen free systems.
Nitrogen and Helium flow cryostats.
Cryogenic liquifiers, Storage tanks.
Systems requiring rapid thermal response.
Specifications
Temperature Range: 1.5K to 400K for the BB and SM packages. 1.5K to 500K for the CP package.
Standard Curve: Cryo-con S900.
Excitation Current: 10μA ±0.1%
Repeatability:10mK @4.2K, 16mK @77K, 75mK @273K.
Magnetic Field Use: Not recommended for fields above 0.1 Tesla or temperature below 40K.
Use in Radiation: Not recommended for high radiation environments.
Maximum Temperature: Do not store above 500K.
Maximum Reverse Voltage: 60V.
Maximum Excitation Current: 2mA.
Power Dissipation: 16μW at 4.2K.
Tolerance Bands
| Band A | ±0.1K | ±0.2K | ±1.0K |
| Uncalibrated | ±0.2K | ±0.4K | ±1.0K |
Temperature Response
Sensitivity (mV/K)
Low Temperature Response
Standard Temperature Response
| 1.5 | 1.63 | -31.5 |
| 4.2 | 1.55 | -38.9 |
| 77.35 | 1.03 | -1.7 |
| 273 | 0.62 | -2.29 |
| 500 | 0.1 | -2.1 |