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Physical Size

The following sizes are standard. Many additional custom mounting configurations and probe assemblies are available.

Useful Temperature Range

Our Silicon Diode temperature sensors operate from 1.5 K to 450 K.

Nominal Sensitivity

Our Silicon Diode temperature sensors have a sensitivity of 40 mvjK

Lead Material

Phosphor Bronze

Either two leaded or four leaded bonded cable, polyimide-coated 32 AWG or 36 AWG . Conductors are color coded. Phosphor Bronze exhibits good electrical conductivity, but poor thermal conductivity. Resistivity is 2.7 Ohms per foot.

Stranded Copper

Teflon-coated wire either two leaded 30 AWG or two and four leaded 36 AWG. Conductors are color coded. Copper exhibits good electrical and thermal conductivity. Resistivity is 0.6 mill i-Ohms per foot.

Manganin

Either two lead or four lead polyurethane-coated 36 AWG. Conductors are not color coded. Exhibits good electrical conductivity, but poor thermal conductivity. Resistivity is 11.8 Ohms per foot. Manganin is not easy to work with.

Lead Configurations

Our Silicon Diode temperature sensors are available in both two and four lead configurations.

Two Lead Configuration

This configuration does not compensate for lead resistance. Therefore, slight errors in sensor resistance/voltage can be induced. The magnitude of the error is proportional to the length of the leads.

Four Lead Configuration

This configuration provides the highest accuracy by compensating for lead wire resistance.

Sensor Accuracy / Interchanqeability

As you review our various sensor types, you will notice that we offer the advantage of
"Grouping" / "Interchangeability." We presently offer five levels of interchangeability /accuracy.

Fundamentally, cryogenic temperature sensors are supplied in three categories:
• Uncalibrated
• Grouped
• Calibrated

Uncalibrated

As the name implies, an uncalibrated sensor is provided to our customers as representative of a particular sensor type, but with no specific calibration information.

Grouped

Certain sensor types exhibit interchange resistance or voltage output characteristics to a standard curve. Grouping sensors offered by Scientific Instruments include:

1. Si-410 Silicon Diode
2. RO-l05 Ruthenium Oxide
3. RO-600 Ruthenium Oxide

The ability to offer interchangeable sensors comes from a thorough analysis and understanding of the basic material to be used as the sensing element. The primary advantage to "grouping" sensors is that they all adhere to a standard V/T or R/T curve, thus eliminating the need and expense of an individual calibration. Each Si-410 sensor is tested in liquid helium, liquid nitrogen and ice. Each sensor must repeat in liquid helium ± 0.01 K over a ten cycle test. The sensors are then grouped according to the following table:

Calibrated

All sensors offered by Scientific Instruments may be offered as individually calibrated units, with the exception of our thermocouples. The sensors are placed into a calibration cryostat, and data is recorded for each sensor using an NIST traceable standard against the ITS-gO standard.

Notes

Standard Configuration

Model Si-410 and Si-420 sensors are normally mounted in a gold-plated copper case with four 36 AWG polyimid coated, color-coded, phosphor bronze leads. Case size is 0.093" diameter by 0.250" long. Special leads of phosphorbronze or manganin wire at various lengths can be furnished at a minimum additional cost. Other packages can be supplied, contact us for details.

Custom Calibration

Individual Model Si-410 sensors can be calibrated at 10 or 100 microamps over various standard temperature ranges at the following accuracies: ± 0.05 K from 1.5 K to 25 K ± 0.10 K from 25 K to 450 K.

Scientific Instruments Warranty

Scientific Instruments Terms & Conditions

MODEL Si410_Information Brochure

Si410 Typical Response_100 microamps

Si410 Typical Response_10 microamps