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CS202F-DMX-20B

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CS202SB-DMX-20B Cold head For Ultra Low Vibration UHV Applications
DMX-20 Ultra Low Vibration Exchange Gas System with Elastomeric Direct Mounts

The CS202*F-DMX-20B is our ultra low vibration closed cycle cryostat for UHV applications. The ARS manufactured DMX-20B interface, like our "B" series cold heads, is a true UHV (10-11 Torr) system where all of the rubber o-ring seals have been replaced with welded joints and metal seals. A CF flange is directly welded to the interface.

The DMX-20B also has the advantage of being easily bakeable to 200 C because the DE-204 cold head can be quickly removed from the DMX-20B interface without breaking vacuum.

The DMX-20 interface opens up a wide range of capabilities never before possible with a closed cycle cryocooler. The CS202*F-DMX-20-OM uses a helium exchange gas to decouple the sample from the cold tip of the DE-202 cryocooler. This prevents almost all vibration from being transmitted to the sample. Scientists have demonstrated vibration levels as low as 3-5 nm with the CS202*F-DMX-20.

Because the exchange gas is inherently less efficient than cooling by conduction, the base temperature of the sample will be 1-2 K higher than the cryocooler. Additionally the DMX-20 interface requires a downward orientation of the cold tip to facilitate convective cooling of the exchange gas.

Download CS202F-DMX-20B Data Sheet

Applications
  • Low vibration UHV applications
  • Microscopy applications
  • Surface science
  • Nanomaterials
Features
  • Ultra low vibrations (3-5 nm)
  • True UHV (10-11 Torr)
  • Bakeable to 200 C with cold head removed
  • Open sample space
  • Cold tip down orientation
  • Fully customizable
Typical Configuration
  • Cold head (DE-202AF)
  • Compressor (ARS-2HW)
  • 2 helium hoses
  • DMX-20 ultra low vibration interface
  • 6" rotatable CF flange
  • Nickel plated OFHC copper radiation shield terminating 0.125" short of the cold tip
  • Instrumentation for temperature measurement and control:
    • 10 pin UHV feedthrough
    • 50 ohm thermofoil heater
    • Silicon diode sensor curve matched to (± 0.5 K) for control
    • Calibrated silicon diode sensor (±12 mK) with 4 in. free length for accurate sample measurement
  • Wiring for electrical experiments:
    • 10 pin feedthrough
    • 4 copper wires
  • Sample holder for optical and electrical experiments
  • Temperature controller
Options and Upgrades
  • 4.5" CF flange available but uses non standard ID and may not fit existing chambers
  • 8" CF flange available
  • 4 K cold head (0.2 W @ 4.2 K) CS204SE-DMX-20 (DE-202S not recommended)
  • 6 K cold head (3 W @ 10 K) CS204PE-DMX-20 (DE-202P not recommended)
  • Turbo upgrade for faster cooldown times
  • 450 K high temperature interface (Not required with the DMX-20 interface, but the 450 K interface is helpful for high temperature performance.)
  • 800 K high temperature interface
  • Custom temperature sensor configuration (please contact our sales staff)
  • Custom wiring configurations (please contact our sales staff)
  • Sample holder upgrades (custom sample holders available)

The ARS Advantage

The Ultra Low Vibration Exchange Gas Interface
A Schematic Representation of the DMX-20 Interface

The X-20 interface uses a helium exchange gas to decouple the sample space from the cold tip of the cryocooler. This prevents almost all vibration from being transferred to the sample space. Scientists have demonstrated vibration levels as low as 3-5 nm with the CS202*E-DMX-20.

1. The cryocooler is supported by a floor stand.
2. The soft rubber bellows minimize the vibrations transmitted to the sample while keeping in the helium exchange gas.
3. The X-20 interface has no contact with the cryocooler except through the rubber bellows.
4. The cold tip has 10-30 micron vibrations (depending on CCR model) but no direct contact with the sample space.
5. Convective pockets of helium exchange gas cool the sample space.
6. The sample is only in contact with the X-20 interface.
7. Windows provide access for optical experiments.
8. The X-20 interface is mounted directly on a (user provided) vibration isolation table.

4 K, 5.5 K, 10 K Fine-Tuned For Your Temperature Range
A Selection of ARS Manufactured Displex Cold Heads

The DE-204SE cold head is a precision machine carefully tuned to achieve temperatures below 4 K with 0.2 W of cooling power at 4.2 K.

The DE-202AEcold head is a rugged workhorse built with power and durability in mind, achieving temperatures below 9 K with 0.5 W of cooling power at 10 K.

The DE-204PE cold head is a hybrid of the the 4 K and 10 K philosophies, achieving a balance that exhibits the best of both worlds, with temperatures below 5.5 K and 3 W of cooling power at 10 K.

High Temperature Options
800K Interface Manufactured by ARS

Our high temperature interfaces use a unique combination of mechanical and thermodynamic properties to create a high temperature thermal disconnect between the cold head and the sample space. This allows for heating of the sample space far in excess of the maximum 355 K temperature of our cryocoolers.

450 K The Easy Way

Our 450 K interface is a simple semi-permanent addition to the cold tip that expands the upper sample temperature range by 95 K utilizing most of the same instrumentation as our standard cryocoolers.

800 K - Pouring on the Heat

Our specially designed 800 K interface goes beyond the standard techniques to provide a unique system that maximizes thermal conduction at low temperatures while minimizing heat transfer at high temperatures. Beyond the safe operating temperature of silicon diodes, the standard sensors are replaced with E-type thermocouples and platinum RTDs.

Wired the Right Way - Your Way
Thermally Anchored Sensor Wiring on the DE-202 Cold Tip

Our technicians painstakingly wrap each cold head for optimum thermal anchoring. We offer you the choice of a variety of wiring options, from our standard offerings of single strand copper and low noise coaxial wiring packages to any number of custom wiring configurations.

Typical instrumentation for temperature measurement and control include one 50 ohm thermofoil heater, one curve matched silicon diode for rough temperature control, and one free length calibrated diode for direct attachment to the sample or sample holder for accurate temperature measurement. Silicon diode sensors are favored heavily for most standard applications because of their low cost, durability, and stability, but we do offer a wide variety of other sensors for different applications such as Cernox sensors for high magnetic fields, E-type thermocouples for 4 K-800 K measurements, and platinum RTDs for accurate high temperature measurements.

Our wide selection of wiring and instrumentation is matched by an equally wide selection of temperature controllers from Cryocon, Lake Shore, and Scientific Instruments.

A Sample Holder for Every Measurement
SHOE-1C Sample Holder for Optical and Electrical Experiments

Whether the measurement is optical or electrical in nature, the sample large or small, we have a sample holder for almost any measurement. The CS202*F-DMX-20B can accept all but our largest sample holders. Like all of our cold fingers, the DMX-20 interface has a 1/4-28 threaded hole on the cold tip to mount the sample holder. So even if you do not find what you need from our wide variety of sample holders there is always the option of attaching a custom sample holder.

Water Cooled Compressor For Your Convenience
The ARS-2HW Compressor

The water cooled ARS-2HW compressor that powers the DE-202 Series cold heads has many benefits that are amplified in small laboratory settings. The water cooling redirects heat energy that would otherwise be dumped into the lab by a large cooling fan. The lack of a large cooling fan also dramatically reduces the noise of these compressors (only 60 dBA). Additionaly with minimum air circulation, the air currents and dust are kept to a minimum. The high efficiency heat exchanger results in low water usage and saves space inside the compressor, giving it a small footprint. When water is not available our Coolpac™ remote recirculation system can send cooling water from up to 100 feet away.

Easy Do-It-Yourself Maintenance
DE-202 Disassembled for Service

The ARS DE-202 Closed Cycle Cryocooler operates on a pneumatically driven Gifford-McMahon refrigeration cycle that is both mechanically simple and robust.

12,000-Hour Maintenance Cycle

Over time the internal components of the cold head begin to wear. Eventually the performance of the cold head will decline and some time after 12,000 hours certain internal components need to be replaced or refurbished. With most closed cycle cryocoolers the only option is to send the cold head back to the manufacturer for service.

A Second Option

The simplicity of the ARS pneumatically driven cryocooler allows for another option. Our customers can purchase a service kit for our 10 K and 5.5 K cryocoolers that replaces all of the worn components. This service kit can be ordered ahead of time and reduce down time to a matter of hours instead of weeks.

DMX-20B Specifications

Cooling Technology-
  DE-202 Closed Cycle Cryocooler
  Refrigeration Type Pneumatically Driven Gifford-McMahon Cycle
  Liquid Cryogen Usage None, Cryogen Free
Temperature*-
  DE-202AF < 10 K - 350 K
DMX-20 interface adds 1-2K to base temperature
  DE-202SF Not Recommended,
see CS204*E-DMX-20 for 4K option
  DE-202PF Not Recommended,
see CS204*E-DMX-20 for 5.5K option
  With 800 K Interface (Base Temp + 2 K) - 800 K
  With 450 K Interface (Base Temp + 2 K) - 450 K
  Stability 0.1 K
  *Based on bare cold head with a closed radiation shield, and no additional sources of experimental or parasitic heat load.
Sample space-
  Diameter Large
Open radiation shield
  Height Large
Open radiation shield
  Sample Holder Attachment 1/4-28 screw
  Sample Holder View our Sample Holder Collection
Optical Access-
  Window Ports N/A
  Diameter N/A
  Clear view N/A
  #/F N/A
  Window Material View our Wide Selection of Window Materials
Temperature Instrumentation and Control (Standard)-
  Heater 1 - 50 ohm Thermofoil Heater Anchored on Cold Tip
  Control Sensor 1 - Curve Matched Silicon Diode
  Sample Sensor 1 - Calibrated Silicon Diode
  Custom Instrumentation Contact ARS for available Options
Instrumentation Access-
  Instrumentation Skirt Welded Stainless steel
  Pump out Port 1 - NW-25
  Instrumentation Ports 2 - mini CF 1.33in
  Instrumentation Wiring Contact our sales staff for wiring options
Vacuum Shroud-
  Material N/A
  Length N/A
  Diameter N/A (at the sample space)
  Width N/A (at the sample space)
Radiation Shield-
  Material OFHC Copper
  Attachment Threaded
  Optical Access Open end
Radiation shield terminates 0.125" short of cold tip (customer specified)
Cryostat Footprint-
  Overall Length 590 mm (23.24 in)
295 mm (11.63 in) standard flange in tip length
  Motor Housing Diameter 114 mm (4.5 in)
  Rotational clearance 200 mm (8 in) with "G" configuration
Chamber Interface-
  Flanges CF, ISO
  Size 4.5", 6", 8", 10"
(4.5" CF flange non standard may not fit all chambers)
DMX-20 Sample Vibrations-
  Optimal Mounting 3 - 5 nm
  Direct Mount Dampeners < 140 nm

DMX-20 Vibration Levels

DMX-20 Vibration Data Showing a 3-5 nm Vibration Peak at the Native 2.4Hz Frequency of the Cryocooler

Cryocooler Specifications

Cryocooler Model DE-202AE DE-202A(T)E DE-202PE DE-202SE
  Frequency 60 Hz 50 Hz 60 Hz 50 Hz 60 Hz 50 Hz 60 Hz 50 Hz
    Base Temperature < 9 K < 9 K < 9 K < 9 K < 5.5 K < 5.5 K < 4.2 K < 4.2 K
    Cooling Capacity- 4.2 K - - - - - - 0.1 W 0.08 W
  10 K 0.5 W 0.4 W 0.7 W 0.56 W 1 W 0.8 W 1.2 W 1 W
  20 K 2.5 W 2 W 3.7 W 3 W 2.3 W 1.8 W 2.3 W 1.8 W
  77 K 4 W 3.2 W 6 W 4.8 W 3.5 W 2.8 W 4 W 3.2 W
    Radiation Shield Cooling Capacity 10 W 8 W 15 W 12 W 10 W 8 W 10 W 8 W
       (1st Stage Cooling Capacity at 77 K)                
    Maximum Cylinder Temperature 355 K 355 K 355 K 355 K
    Cooldown Time- 20 K 50 min 60 min 35 min 42 min 60 min 72 min 60 min 72 min
  Base Temperature 70 min 84 min 50 min 60 min 90 min 108 min 90 min 108 min
    Weight Expander 7.1 kg (16 lbs) 7.1 kg (16 lbs) 7.1 kg (16 lbs) 7.1 kg (16 lbs)
Compressor Model ARS-2HW ARS-4HW ARS-2HW ARS-4HW
    Standard Voltage Min 208 V 208 V 208 V 190 V 208 V 190 V 208 V 190 V
  Max 230 V 220 V 230 V 210 V 230 V 210 V 230 V 210 V
    Power Usage Singe Phase 1.3 kW 1.2 kW 3.6 kW 3.0 kW 3.6 kW 3.0 kW 3.6 kW 3.0 kW
    Dimensions: L 483 mm (19 in) 483 mm (19 in) 483 mm (19 in) 483 mm (19 in)
  W 434 mm (17.1 in) 434 mm (17.1 in) 434 mm (17.1 in) 434 mm (17.1 in)
  H 516 mm (20.3 in) 516 mm (20.3 in) 516 mm (20.3 in) 516 mm (20.3 in)
    Weight Compressor 62 kg (137 lbs) 73 kg (160 lbs) 73 kg (160 lbs) 73 kg (160 lbs)
    Typical Maintenance Cycle 12,000 hours 8,000 hours 12,000 hours 12,000 hours
CS202*F-DMX-20B Full Cryostat Drawing

CS202*F-DMX-20B
Full Cryostat
Ultra Low Vibration, Ultra High Vacuum

A Typical DMX-20 Installation Showingthe Motor Housing being supported by a floor stand and the Ultra Low Vibration Interface Supported by a Vibrationally Isolated Optical Table

CS202*F-DMX-20
Typical DMX-20 Installation

ARS-2HW Compressor Drawing

ARS-2HW
Compressor

Click on the images for full size.
Ultra Low Vibration, Closed Cycle Cryostat
for Scanning Electron Microscope Model JSM-5910 SEM






"The cold head is connected to a modified SEM sample stage (with heater) using flexible OFHC copper braids to enable maximum movement, rotation, and articulation of the sample over an area of ~25 cm². The vibration isolation enables a spatial resolution of ~30 nm during cooling. The sample temperature on the SEM cold stage is continuously adjustable from ~40 K to 320 K. A number of variable temperature time-resolved cathodoluminescence (CL) studies have been performed with this system."

Courtesy of: Prof. Dan Rich
Department of Physics
Ben-Gurion University of the Negev


Proprietary copper braids for maximum thermal transfer, and soft to minimize mechanical vibration.