Cryogenic Temperature Probes

Series 44 Temperature Probe Cryogenic Temperature Probes scientific instruments

The Series 44 Temperature Probes are constructed of stainless steel and are hermetically sealed units allowing for installation into hazardous environments.

Series 44 Temperature Probe: Cryogenic Temperature Probes from Scientific Instruments

Scientific Instruments is the proven leader in cryogenic temperature probe design and the Series 44 Temperature Probe. SI was the sole source for ground support temperature transducers for the entire life of Space Shuttle Program. This trend continues today through the manufacture of several NASA designed probes along with our support of the private space community commercial crew programs.

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

The basic sensing elements used in temperature probe assemblies designed and manufactured by Scientific Instruments, Inc. are our Series Si410 silicon diodes. These diodes are rugged, wide-range sensing elements which offer excellent interchangeability to standard temperature-versus-voltage curves. This interchangeability allows a user to employ any given temperature probe assembly in his facility while using a single temperature curve for signal conditioning requirements. Platinum Resistance Probes are also available.

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All wetted areas are 316 SS.

Insertion Length

2” to 30” customer specified.

Media Connection

MS-33656-E4 Boss seal capable of withstanding 2000 PSI media pressure.

Temperature Range

Series 44B – -40°C to +290°C
Series 44C – -260°C to +125°C
Series 44D – -255°C to +125°C

Insulation Resistance

Greater than 100 megohms at 50 VDC between all terminals in parallel and case.


1.0 mA DC, four leaded. 10μA for diodes.

Ice Point Resistance

Series 44B – 200 +/- 1.0 Ohms
Series 44C – 1000 +/- 1.0 Ohms

Ice Point Output

Series 44D – 0.6180 V +/- .0128 V

Sensor Coefficient

.003890 Ω/Ω/°C determined from calibration data taken at 0°C and 100°C.

  • SI Part NumberTemperature RangeCorresponding *SCM
  • 44B-XXX-40°C to +290°C
    (200 ohm) for use
    with 39C *SCM.
  • 44C-XXX-260°C to +125°C
    (1000 ohm PRT) for use
    with 39C *SCM.
  • 44D-XXX-255°C to +125°C
    (Silicon Diode) for use
    with 39D *SCM.
  • (*SCM = Signal Conditioning Module)


Ending letter (X) defined by probe insertion length available from 2” to 30” customer specified.

For more information, please send us an email or call us at 1-800-466-6031. A Scientific Instruments associate will be happy to assist you.

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