10 K cryocoolers — vibration isolated cryocoolers
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 CCS-100-XG/204N
Temperature range: <8 K to 300 K (at sample mount)
Initial cooldown time: <2 h to 10 K
Power requirements: single-phase: 200, 220, 230/240 V (±5%) 50 Hz; 208/230 V (±5%) 60 Hz
Cooling water requirements: 2.7 L/min at 4 to 27 °C
(Specifications exclude radiational or experimental heat load, and are rated at 60 Hz)
The system includes:
- Model CH-204N 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.
UHV configurations
The Model CCS-XG-UHV/204 system is designed to fit in a UHV chamber and provide the same ultra-low vibration through the use of helium exchange gas. An added advantage of using this system is that the body and sample area of the cryostat are truly UHV compatible and can be baked up to 500 K. Temperatures higher than ~350 K will damage most cold heads, but the design of this system allows the cold head to be removed while the system is baked. The cold head and rubber bellows can be removed while being baked, then reattached and exchange gas introduced to cool the system, all the while, maintaining the UHV environment surrounding the sample.
Model CCS-XG-UHV/204
Temperature range: ~10 K to 300 K (at sample mount)
Initial cooldown time: <2.5 h to 10 K
Power requirements: single-phase: 200, 220, 230/240 V (±5%) 50 Hz; 208/230 V (±5%) 60 Hz
Cooling water requirements: 2.7 L/min at 4 to 27 °C
Bakeable to 500 K (with cold head and rubber bellows removed)
(Specifications exclude radiational or experimental heat load, and are rated at 60 Hz)
The system includes:
- Model CH-204 two-stage cold head and water-cooled compressor
- Exchange gas vibration isolation design with flexible rubber bellows connecting cold head to cryostat
- Exchange gas valve manifold to pump out and flow helium exchange gas
- Outer vacuum shroud with 6-pin UHV electrical feedthrough, evacuation valve, and safety pressure relief valve
- 6 ft rotatable conflat flange to mount to UHV chamber
- UHV compatible copper sample mount with a heater and UHV compatible temperature sensor.
Microscopy configuration
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 CCS-XG-M/204N
Temperature range: ~8 K to 300 K (at sample mount)
Initial cooldown time: <2 h to 10 K
Power requirements: single-phase: 50 Hz: 200, 220, 230/240 V (±5%) 60 Hz: 208/230 V (±5%)
Cooling water requirements: 2.7 L/min at 4 to 27 °C
(Specifications exclude radiational or experimental heat load, and are rated at 60 Hz)
The system includes:
- Model CH-204N two-stage cold head and water-cooled compressor
- Exchange gas vibration isolation design with flexible rubber bellows connecting cold head to 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 a temperature sensor