Series 56 Cryogenic Temperature Probes

Scientific Instruments offers a variety of temperature probes that allow mounting in hazardous environments. These units are constructed of stainless steel, hermetically sealed, and the sensing element is mounted in a thermal epoxy at the tip. The probes are designed for direct immersion or thermowell applications.

Previously known as the Series 46 temperature probe, the series 56 probe assemblies are designed for use with SI-540 silicon diodes configured for either a 10 or 100uA excitation current.

These diodes are rugged, operate within a wide-range (1.5K to 450K) and are interchangeable, utilizing a standard temperature-versus-voltage curve. This interchangeability allows a user to employ any given temperature probe assembly under the same P/N in their facility, while only using a single standard temperature curve for signal conditioning requirements and data acquisition. This model is used in ground support and for flight hardware. See below for detailed specifications.

Additional information

Enclosure

All wetted areas are 316 SS. (Passivated Post Weld Per SAE AMS2700)

Insertion Length

Customer specified. (minimum 1” Insertion length for standard options)

Sensing Element

The sensing element is a silicon diode supported and contained in a hermetically sealed closed housing.

Media Connection

Pressure Fitting: 7/16-20 UNJF-3A THREAD. (Conforming to AS4395E04)
Electrical Connection: MIL-DTL-3899 TYPE 27

Temperature Range

Each unit is capable of operating within an environmental temperature range of 1.5 K (-271.66°C) to 400 K (126.85°C)

Operating Current

The operating current of the unit should be 10 microamperes (µA) ± 0.1µA for the 56D units and 100µA ± 1µA for 56DX (the sensor excitation is supplied by an external signal conditioner).

Service Media

The unit will operate in the following gaseous or liquid media where compatible with the sheath-housing material and within the temperature range of the unit: Hydrogen (LH₂) Oxygen (LO₂), Methane (LCH4), Nitrogen (LN₂), Helium (LHe), Neon (LNe), Argon (LAr), Alcohol (C2H2OH), Ammonia (NH₃) Nitrogen Teroxide (N₂O₄) Hydrazine (N₂H₄) Unsymmetrical Dimethylhydrazine (UDMH) Monomenthylhygrazine (MMH), and Water (H₂O)

Repeatability

The unit is capable of repeating test parameter results under identical test conditions, within ± 0.1K (± 5 mVDC) at the boiling point of liquid helium and within ± 0.5K (1.2 mVDC) from 25 K to 400 K.

Accuracy

The unit shall be accurate to within ± 0.5K from 1.5K to 400K. (Tighter accuracy tolerances available, please consult with factory)

Response Time

Time Response: <5 sec to 63.2%