HelioxTMVT, 3He refrigerator, vacuum loaded to fit into a VTI

This sample-in-vacuum 3He refrigerator achieves less than 300mK for more than 40 hrs and achieves 50 µW of cooling power at 350 mK for over 6 hrs.

As it uses the cold gas environment of the VTI (with 30 or 50 mm access) , there is no need for a 1K pot on the insert. This provides two key benefits:

The sample temperature range of a new or existing VTI can be extended below 280mK
There is no liquid helium in the sample horizontal plane making the Heliox®VT ideal for neutron or X-ray scattering experiments

The design of this system is unique and protected by patent US5829270.

Specifications
System components/options
Operation
Applications
Images

Temperature range	< 300mK – 1.2 K. Higher temperature option available : up to 300 K
Cooling power	> 50µW at 350mK for over 6 hrs
Temperature stability	± 3 mK below 1.2K
Operating time at base temperature (no heat load)	> 40 hrs
3He regeneration time	Typically 40 min
Sample space access	25 mm for VT30, 43 mm for VT50

A complete system consists of:

HelioxVT insert
Temperature controller to operate the refrigerator
A variable temperature insert (VTI) with pump and temperature controller

Options

Sample holder for high field magnet
Spare IVC tail, to suit magnet if required
VTI
High temperature option

The Heliox VT 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.

IntegraAC recondensing dewar compability sketch

The figure below represents a schematic of the HelioxVT running in a VTI. The HelioxVT insert can be treated like any sample rod for a variable temperature insert. Once loaded, the insert is cooled by the VTI from 300K down around 10K using exchange gas. The 3He gas contained in a small dump sitting on top of the insert is then condensed at around 1.5K. Once the 3He pot has reached a stable temperature and condensation is completed, the adsorption pump will start to cool the 3He pot and experimental set-up to below 300 mK. The condensation and the cool down time typically require less than 1 hour.

Research areas	Applications	Experimental techniques
Semiconductors	Quantum Hall Effect Quantum dots Single electron tunneling Quantum computing	Magneto-resistance Hall effect RF transport High frequency conductivity
Solid State Physics	Heavy fermions systems Metal insulator transition Spin glass Mesoscopic systems Giant magnetic resistance	Specific heat DeHaas-van Alphen Oscillations Solid state NMR Electrical resistivity Magneto-resistance Neutron scattering
Superconductivity	Low Tc superconductors Quantum computing Josephson junctions Flux vortices Quantum initial phenomema	Electrical resistivity Scanning spectroscopy(STM/AFM) Squids AC susceptibility
Astrophysics & Cosmology	Low temperature detectors Superconducting tunnel junctions Ge bolometers	Electrothermal measurements Voltage biased measurements Low energy photon detection
Metrology	Quantum Hall Effect Voltage standards Current standards	Magneto-resistance DC & AC low frequency transport and magnetic measurements Single electron tunneling