SVT-200, 300, 400

SuperVariTemp Cryostat Systems

Model SVT-200-5 SuperVariTemp cryostat from Janis Research. Click on photo for larger view.

The Janis Research SuperVariTemp (SVT) system is the basis for a variety of variable temperature cryostats. Offering quick sample exchange, an operational range of 1.4-300 K and highly efficient operation, this versatile system is often incorporated into Janis' CNDT series dewars or, for maximum flexibility, this concept is applicable with virtually any dewar.

By controlling the temperature of the flowing helium vapor in which samples are immersed, both the sample and holder are simultaneously cooled to the same temperature, thereby eliminating the need for thermal anchoring and sample mount heating. The helium flow rate and heater current are balanced to provide flowing vapor/sample temperatures over the range of 1.4-300 K; automatic temperature controllers together with application specific thermometry provide accurate and precise temperature control.

The SVT cryostat makes full use of the cooling power of escaping helium vapor as it exits the sample chamber, resulting in improved efficiency over exchange gas systems. Operation of the SVT typically adds about 0.1 L/hr to the total liquid helium evaporation rate of the dewar. The sample chamber is thermally isolated from the helium reservoir by the dewar vacuum, thereby eliminating heat conduction into the reservoir. This provides for low helium consumption rate even at higher sample temperatures.

The SVT's unique design allows for operation below 4.2 K without wasteful pumping on the main helium reservoir. Operation below lamda is readily achieved with the sample immersed, either in liquid or vapor, by simply throttling the rate of helium introduced to the sample chamber while evacuating the sample tube.

ALL SVT MODELS INCLUDE:

Janis Research SuperVariTemp system
Top-loading sample positioner
One (1) 10-pin and two (2) 8-pin electrical feedthroughs
Safety pressure relief valve
System test

Options include:

Isothermal zone sample tube (provides uniform sample temperature and enhanced operation with LN₂)

Typical SuperVariTemp variable temperature System from Janis Research, cryogenics
Typical SuperVariTemp System

Table of Contents
SVT-200 Optical Systems
Optical cryostat for experiments requiring long hold times or a
larger sample space, featuring a 6 liter liquid helium capacity.
SVT-200T Tubular Systems
Non-optical cryostat for experiments requiring long hold times or
a larger sample space, featuring a 6 liter liquid helium capacity.
SVT-200T-NMR Tubular Systems
Similar to the standard SVT-200T, but custom designed for
NMR Spectroscopy.
SVT-300 Optical Systems
Designed with long-running experiments in mind, this optical
cryostat features an increased liquid helium efficiency and
a 5 liter helium capacity.
SVT-300T Tubular Systems
This cryostat incorporates an increased liquid helium efficiency
in a tubular tail design for long-running non-optical experiments.
SVT-400 High Efficiency Variable Temperature Cryostat
The system's ultra-low cryogen consumption, remarkable
    temperature homogeneity and stability make it ideal for long or short
    term experiments.
Double Rotating Sample Positioner
Janis offers special sample positioners with the ability to rotate the
    sample about the optical axis of the cryostat.

Options & Accessories

JANIS RESEARCH COMPANY, INC.
2 Jewel Drive, P.O. Box 696
Wilmington, MA 01887-0696 USA
TEL: +1-978-657-8750 FAX: +1-978-658-0349
E-Mail: sales@janis.com
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