The KelvinoxMX uniquely separates the cooling platform from the experimental services. This offers : Flexibility to change experimental configurations and thermodynamic performances if needed. Multiple users to carry out different configured experiments, with minimum downtime. Access to different applications by selecting the appropriate experimental insert. Simple diagnostics: experimental wiring and set-up can be easily tested. Full automation : all inserts are supplied with a gas handling system (KelvinoxIGH) enabling automation of the insert cool down. The KelvinoxMX is made up from three main components: primary insert, dilution unit and experimental insert.
The KelvinoxMX is made up from three main components:
Automation and control of your dilution refrigerator using the KelvinoxIGH - Intelligent Gas Handling system :
All systems are delivered with a KelvinoxIGH which is a fully automated system which enables complete operation of a dilution refrigerator using sophisticated software and virtual instrument drivers for National Instruments'LabVIEWTM.
Solutions to helium rising costs :
The KelvinoxMX is compatible the IntegraAC, recondensing liquid helium cryostat.
This product has been developed to significantly reduce the consumption of liquid helium by recondensing helium gas evaporated within the system, which would other wise be vented from the cryostat. This decreases the frequency of helium refills. Cryogenic systems can be kept cold continuously, even when in stand by mode, leading to greater freedom to schedule experimental time.
The Dilution Process:
When a mixture of 3He and 4He is cooled below 870 mK, it separates into two phases. The lighter 'concentrated phase' is rich in 3He and the heavier 'dilute phase' is rich in 4He. The concentration of 3He in each phase depends upon the temperature. Since the enthalpy of the 3He in the two phases is different, it is possible to obtain cooling by evaporating the 3He from the concentrated phase into the dilute phase.
These concentrated and dilute phases separate and a phase boundary established in the mixing chamber, where the cooling process takes place.
To establish continuous cooling one must promote the flow of 3He across the phase boundary in a continuous process. This is achieved by raising the temperature of the dilute phase to ~700 mK outside of the mixing chamber in the still. The vapor pressure of 3He at this temperature is two orders of magnitude higher than that of 4He allowing 3He to be preferentially pumped using external room temperature mechanical pumps or charcoal sorption pumps. This exhausted 3He can be returned to the system, condensed on the 1K pot, pre-cooled at the still and then further cooled through heat exchange with the exiting stream using a continuous heat exchanger ~150 mK and a series of silver sinter step heat exchangers from 100 mK to 20 mK, before being reintroduced to the mixing chamber to continue the process.
To protect the cooling platform from heating the dilution unit and 1K pot are housed in a vacuum with a radiation shield from either the still or 100 mK cold plate that surrounds the heat exchangers and sample space below the mixing chamber.
With careful design temperatures below 5 mK are achievable with a dilution refrigerator.
The KelvinoxMX design allows the cryogenic cycle of the dilution refrigerator and the experimental wiring to be kept seperate. The experimental insert is interchanged at room temperature using the large 50 mm line-of-sight port on the primary insert. Once the experimental insert is aligned with the primary insert, thermal straps secure the two together. These thermal straps are designed to be easy to use whilst also ensuring an optimised thermal link. The sealing between the primary insert and the experimental insert is formed at the top place by an O-ring seal and a novel design of indium seal at the IVC flange. The system is then ready to be cooled down as a standard dilution refrigerator.