Products

4 Kelvin Closed Cycle Refrigerator Systems from Janis and SHI

Sample in Static Exchange Gas - SHI-950 and SHI-850 Series

Overview

Click button below to enlarge view of SHI-950-15 4 Kelvin closed cycle refrigerator with sample in static exchange gas, reference 17043, This system is shown with black powder-coat finish on the vacuum shroud.  The mounting stand and lifting bar assemblies were black anodized.  Janis Research, Sumitomo, SHI, cryogenic equipment

Janis exchange gas systems offer two main advantages to the experimenter: rapid sample exchange while the refrigerator is operating, and efficient cooling for non-conductive or irregularly shaped samples not easily clamped to a cold finger (e.g., powders, liquid solutions, etc.). These advantages are made possible by using the refrigerator to cool a column of helium exchange gas surrounding the sample. The sample is inserted, via a long rod, into a nearly isothermal region of the gas column for cooling. Sample exchange by simply removing the sample rod, switching samples on the rod, and reinserting the rod into the cryostat. The entire sequence takes only a matter of minutes and is performed while the refrigerator is operating. Thus the time to cool successive samples is greatly reduced as compared with sample in vacuum cryostats.

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Standard Configuration

Janis exchange gas systems offer two main advantages to the experimenter: rapid sample exchange while the refrigerator is operating, and efficient cooling for non-conductive or irregularly shaped samples not easily clamped to a cold finger (e.g., powders, liquid solutions, etc.). These advantages are made possible by using the refrigerator to cool a column of helium exchange gas surrounding the sample. The sample is inserted, via a long rod, into a nearly isothermal region of the gas column for cooling. Sample exchange by simply removing the sample rod, switching samples on the rod, and reinserting the rod into the cryostat. The entire sequence takes only a matter of minutes and is performed while the refrigerator is operating. Thus the time to cool successive samples is greatly reduced as compared with sample in vacuum cryostats.

Click button to enlarge view of mechanical drawing for standard, optical SHI-950-x configuration 4 Kelvin closed cycle refrigerator from Janis Research, sample in static exchange gasEnlarge

Standard Optical (SHI-950-x) Configuration Mechanical Drawing

Click button to enlarge view of mechanical drawing for non-optical tail and brackets for models SHI-950T and SHI-950T-5 4 Kelvin closed cycle refrigerators with sample in static exchange gas from Janis Research, Sumitomo, SHI, cryogenic equipment, cryocoolersEnlarge

Non-optical Tail and Brackets for Models SHI-950T and SHI-950T-5

The cooler is mounted above the sample chamber in these cryostats. This design permits the sample region to be inserted into the sample chamber of a spectrometer or the room temperature bore of a superconducting magnet.

Optimized for experiments requiring optical access to the sample, the SHI-950 and SHI-950-5 systems include the following components:

  • Isothermal static helium gas sample chamber, with exchange gas introduction valve
  • Optical vacuum shroud and radiation shield
  • Gold-plated OFHC copper sample holder
  • Adjustable sample positioner with 8-pin and 10-pin electrical feedthroughs for thermometry and customer wiring into the sample area
  • Two spare electrical access ports
  • Evacuation valve and safety pressure relief
  • Four-way optical access into the sample chamber
  • Silicon diode thermometer and control heater

Available options:

  • Additional electrical feedthroughs (BNC, SMA, multipin, and others)
  • Additional window ports
  • O-ring or epoxy sealed windows
  • Indium sealed strain relief mounted cold windows
  • IR and other window materials
  • Larger or smaller diameter sample chamber
  • Special sample positioners, including a double rotating sample positioner for sample rotation about the optical axis (Model SHI-950)
  • Non-optical configurations
  • Compact configurations (for use with electromagnets)
  • Custom configurations

Standard models include:
("x" indicates the cooling power of the refrigerator)

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Specifications

SHI-950 Series

SHI-950 SHI-950-5 SHI-950T SHI-950T-5
Temperature Range ~4.5 K to 300 K ~4.5 K to 300 K ~4.0 K to 300 K ~4.5 K to 300 K
Initial Cooldown Time ~3.5 Hours to 4.5 K ~6 Hours to 4.5 K ~2.5 Hours to 4.5 K* ~6 Hours to 4.5 K
Sample Change Time 5 Minutes 5 Minutes 5 Minutes 5 Minutes
Cold Head RDK-408D2 RDK-205D RDK-408D2 RDK-205D
Cryostat Weight ~100 lbs. ~95 lbs. ~100 lbs. ~95 lbs.
Compressor Cooling Air or Water Water Air or Water Water
*Typical. May vary with system configuration.

Other Configurations

Special designs include:

Click image to enlarge view of model SHI-550T-1 4 K cryocooler with sample in static exchange gas.

Model SHI-550T-1
This system was built with a customer-supplied 0.1 W cold head, but would work well with a 0.5W cold head.  Model SHI-550T is similar to the SHI-950T, but with the cooler mounted below the sample chamber.  Please contact us for specifications.

Click image to enlarge view of SHI-950T with black anodized mounting stand.  Reference 16526

SHI-950T with Black Anodized Mounting Stand
Ask your Janis sales engineer about black anodized mounting stands

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