4 K cryocoolers — vibration isolated

In a traditional closed cycle refrigerator system, samples are mounted directly to the cold head. When the system is operated, the several micron-sized vibrations, inherent in every closed-cycle system, are transmitted directly from the cold head to the samples.

CCR-XG systems are specifically designed to minimize vibrations at the sample, while at the same time utilizing a closed-cycle refrigerator and providing a sample in a vacuum environment. These systems isolate the vibrations of the cold head from the sample by using helium exchange gas and rubber bellows. Instead of being attached directly to the cold head, the sample is mounted to a stage that is not connected to the cold head, yet is cooled via helium exchange gas. This arrangement allows the sample to cool, while simultaneously reducing the vibrations. The rubber bellows connects the body of the cryostat to the cold head. When the cryostat and cold head are supported separately, little to no vibrations reach the body of the cryostat via the rubber bellows.

Standard configuration

The Model CCS-100-XG/204N (10 K) and Model SHI-4XG-5 (<5 K) systems replace the traditional optical closed-cycle sample in vacuum systems: CCS-100/204 and SHI-4-1, respectively. The exchange gas isolated versions are very similar in appearance and function to the traditional optical systems, but greatly reduce the vibrations observed at the sample.

Model SHI-4XG-5

Temperature range: <5 K to 300 K (at sample mount)

Initial cooldown time: <2 h to 10 K

Power requirements: 200 VAC, 3-phase, 50/60 Hz, 2.8 kW

Cooling water requirements: ~3.3 L/min at 4 to 28 °C

(Specifications exclude radiational or experimental heat load, and are rated at 60 Hz)

The system includes:

• Model RDK-205E two-stage cold head and water-cooled compressor
• Exchange gas vibration isolation design with flexible rubber bellows connecting cold head to the cryostat
• Exchange gas valve manifold to pump out and flow helium exchange gas
• Outer vacuum shroud with electrical feedthroughs, evacuation valve, and safety pressure relief valve
• Standard optical sample holder, a heater, and a temperature sensor

Other configurations

Microscopy configurations

The Model CCS-XG-M/204N and SHI-4XG-5-M systems both have a horizontal extension making them ideal for optical microscopy experiments. These extensions are roughly 1.5 in tall to allow them to fit in many optical microscopes. In addition, the horizontal extension allows the sample to be positioned very close to the top window, an essential feature for short focal length microscope objectives. This horizontal extension also allows for easy sample changes; simply remove the horizontal extension top plate and radiation shield plate to access the sample area.

Model SHI-4XG-5-M

Temperature range: 4.2 K to 300 K (at sample mount)

Power requirements: 200 VAC, 3-phase, 50/60 Hz, 2.8 kW

Cooling water requirements: ~3.3 L/min at 4 to 28 °C

(Specifications exclude radiational or experimental heat load, and are rated at 60 Hz)

The system includes:

• Model RDK-205E two-stage cold head and water-cooled compressor
• Exchange gas vibration isolation design with flexible rubber bellows connecting cold head to the cryostat
• Exchange gas valve manifold to pump out and flow helium exchange gas
• Outer vacuum shroud with electrical feedthroughs, evacuation valve, and safety pressure relief valve
• Horizontal vacuum shroud extension with top and bottom quartz windows
• Horizontal cold finger extension with an optical sample holder, a heater, and temperature sensor.