Cryostats

Four cryostats can be supplied for applications that require sample manipulation. The range includes three open cycle cryostats and a closed cycle refrigeration system. Our own Cryostats together with those from ARS are integrated with VG Scienta manipulation to provide a powerful range of cryogenic manipulators for a wide range of applications.
The Cryoax 2 Cryostat
The Cryoax has been developed by VG Scienta to achieve the minimum sample temperature with 5 axes of movement. The Cryoax 2 can be fitted with VG Scienta sample holders. Two cooling circuits are provided: the main circuit cooling the sample plate via the syphon entry which permits either liquid nitrogen or helium cooling. A secondary liquid nitrogen cooling system is provided for the radiation shield. This construction thermally isolates the sample from any heat source. Sample heating to 1200°C is available.
The Helistat Cryostat
The Helistat has been developed by VG Scienta for fast response and for low temperature angular resolved work. The low mass heat exchanger is mounted close to the sample and connected to it by high conductivity flexible braid. The Helistat uses the same LHe and LN2 transfer equipment as the Cryoax. Sample heating to 1200°C is available .
The Helitran Cryostat
The Helitran LT-3B from ARS is fully compatible with the Omniax manipulator and provides primary rotation. The Helitran can be used with either liquid helium or liquid nitrogen withouit any modification, and can provide a base temperature of 4.2k without pumping. Optional temperature range is 4-800k. Unique design features like a shielded flow transfer line and a matrix heat exchanger at the sample tip permit high cooling power, and a high temperature stability at the sample. A wide range of sample mounts can be installed at the tip.
The Displex Closed Cycle System
The Displex DE-202 (or DE-202N) from ARS is a closed loop cycle cryocooler with an axial design for ease of compatibility with the Omniax. The axial geometry permits primary rotation of the cryocooler when installed on the manipulator. Temperature at the tip of the cooler is 10-350k without use of liquid helium or nitrogen (6-800k as an option). The cryocooler has a pneumatic drive to ensure low vibration at the sample. A wide range of sample mounts can be installed at the tip of the cryostat.

Specifications: All data is approximate and depends on the nature of the sample and experimental conditions.

	CRYOAX 2 ¹	HELISTAT	HELITRAN	DISPLEX
Maximum Degrees of Freedom	Up to 5 axes	Up to 5 axes	Up to 4 axes	Up to 4 axes
Liquid Helium:
Cold finger base temperature	13K	13K	4.2K	10K (6k option)
Sample mounting plate temperature with secondary rotation²	50K²	60K²	-	-
Maximum temperature with resistive heater	1223K(950°C)²	1223K (950°C)²	300K (27°C) (option 800K)	350K (77°C) (option 800K)
Maximum temperature with EB heater	1473K (1200°C)²	1473K (1200°C)²	-	-
Cool down consumption	2 litres	1 litre	1.5 litres	-
Running consumption rate	2 litres/hour	2 litres/hour	1 litre/hour	None
Cool down time	1 hours	30 min	35 min	20K in <60 mins.
Liquid Nitrogen:
Base temperature	98K (175°C)²	103K (-170°C)²	77K (-196°C)	-
Sample mounting plate temperature with secondary rotation²	108K (-165°C)²	113K (-160°C)²	-	-
Maximum temperature with resistive heater	1223K (950°C)²	1223K (950°C)²	300K (27°C)	-
Maximum temperature with EB heater	1473K (1200°C)²	1473K (1200°C)²	-	-

Notes:
1 The Cryoax data is given without the radiation shield fitted. The shield will improve the base temperature, depending on the amount cut away for sample access.
2 These temperatures are given for sample mounting plate of the SH2 sample holder to permit R2 (azimuthal) rotation of the sample in addition to normal R1 (primary) rotation. This typical configuration is not adapted for cryogenic use.

Cryoax 2

· Base temperature <13K. Can be used for up to five axes of manipulation.

· The Cryoax 2 uses an open cycle cryostat mounted on an Omniax translator with a standard support tube of 28mm ID.

· The Cryoax 2 has a wide range of movement options in five axes. Fully bakeable to 230°C, once any motors and transfer syphon are removed.

· Compatible with Thermo VG Scienta sample holders. The standard range of Sample Holders is shown on page 242 of our catalogue

· Sample heating to 950°C is possible with resistance heating.

· Liquid nitrogen transfer requires a different syphon which is interchangeable with the helium syphon.

· Can be mounted vertically or horizontally (but not inverted).

· The probe insertion length, L, can be made to suit most requirements. Some limits may apply. Please refer to the basic Omniax dimension.

· Four service feedthrough ports are fitted. All wiring should be specified with the order.

Helistat

· Base temperature <13K. Can be used for up to five axes of manipulation. Rapid temperature response with stable secondary movement.

· The Helistat is mounted on the Omniax translator with a wide range of movement options. The standard support tube is 28mm ID.

· Fully bakeable to 230°C, once any motors and transfer syphon are removed.

· Compatible with Vacuum Generators sample holders. The standard range of Sample Holders is shown on page 242 of our catalogue.

· Sample heating to 1200°C is possible.

· Liquid nitrogen transfer requires a different syphon which is interchangeable with the helium syphon.

· Can be mounted vertically or horizontally (but not inverted).

· The probe insertion length, L, can be made to suit most requirements. Some limits may apply. Please refer to the basic Omniax dimension.

· Includes to ‘N’ type Thermocouples.

· Four service feedthrough ports are fitted. All wiring should be specified with the order.

HeliTran

· Base temperature of 4.2K. This can be further reduced by pumping the exhaust gas. Cooling power of 0.75 Watts at 4.2K on the cold tip.

· The Heli-Tran from ARS is mounted on the Omniax translator with a wide range of movement options in up to 4 axes.

· The ARS transfer line has a patented shield flow which stabilises flow to reduce oscillations and minimise consumption.

· Liquid nitrogen transfer uses the helium syphon without modification.

· Fully bakeable to 200°C, once any motors and the transfer syphon are removed.

· Can be mounted in any orientation.

· The probe insertion length, L, can be made to suit most requirements. Some limits may apply. Please refer to the basic Omniax dimension.

Displex

· Two stage Gifford-McMahon refrigerator from ARS, mounted on an Omniax translator.

· The Displex can achieve and maintain temperatures as low as 10K (6k option) at the cold tip of the cryocooler.

· Temperatures range up to 350K.

· Refrigeration capacity: 0.5 Watts @ 10 Kelvin @ 60Hz.

· The Displex can be used with four manipulation axes. The arrangement shown provides rotation about the mounting port axis, since XY stage is mounted above the rotary module. Alternative arrangements can be supplied to give rotation about the Displex probe axis.

· No helium consumption.

· Conflat flange mounting.

· The Displex can be mounted vertically or inverted only.

· The Displex is supplied with the compressor and connecting hoses.

· The probe insertion length, L, can be made to suit most requirements. Some limits may apply. Please refer to the basic Omniax dimension.

Displex® is a registered trademark of APD Cryogenics Inc.

Open Cycle System Operation for Cryoax and Helistat
LIQUID HELIUM Vacuum Method: By reducing the pressure of the exhaust gas, the boiling point of the helium is also reduced, lowering the base temperatures. A combined flow pump regulator kit is available. Refer to the section below.
Pressure Method: Liquid helium is forced from the pressurised storage dewar and into the cryostat. This is a simpler method of operation, but the boiling point of the helium is increased, and some flow instability can result.
LIQUID NITROGEN Dry nitrogen gas from a pressurised bottle is condensed and transferred to the cryostat. Note that the helium transfer syphon used on the Cryoax 2 and Helistat, is not suitable for liquid nitrogen transfer. A simplified nitrogen syphon is available for these units. Refer to the section below.

Open Cycle Transfer Syphons