HelioxTMAC-V, 300 mK Cryogen-free 3He cryostat

HelioxAC-V Cryofree 3He refrigerator insert

The HelioxAC-V is a compact Cryofree system able to cool large samples below 300 mK for more than 50 hours without the need for liquid helium.

Un-rivalled experimental capability.

The system further benefits from:

Unique design : The HelioxAC-V uses a proprietary cryogenic cycle (US patent 6782712 and European patent application 1387133) using adiabatic multi-expansion of 3He gas
Wide temperature range from 300 mK to 300 K
High temperature stability :
Professor Leonid Kuzmin from the Quantum Device Physics Laboratory from Chalmers University (Sweden) demonstrated a temperature stability of +/- 250 µK over a period of 8 hours with a temperature resolution of +/- 100 µK. Click here to purchase the full article "Array of SIN tunnel junctions as a sensitive thermometer" .
3He storage dumps and pumping system are contained within the system enabling a compact design - just 0.4 m diameter and 0.85 m high
No blockages can occur during operation thanks to the built-in cryogenic pump which traps contaminants
Large sample space : Up to 147 mm diameter and 100 mm high, allowing the system can accommodate complex experimental set-ups.
The HelioxAC-V can be integrated into a Cryofree magnet for a complete Cryofree solution.

Specifications
System components/options
Operation
Applications
Images

Sample environment	Vacuum
Sample space	130 mm diameter x 100 mm height
Base temperature (no applied heat load, with standard radiation shields)	<= 300 mK for more than 50 hrs
Maximum temperature	300 K as standard
Cooling power (with radiation shields)	100 µW at 350 mK for > 6 hrs
Temperature stability	±3mK at T<=2K; ±0.1K at T>2K (measured over a 10 min period; see note 1.)
Thermometers	Uncalibrated RuO2 sensors and calibrated Cernox sensors on 3He pot, uncalibrated carbon sensors on sorb and other critical control elements.
3He regeneration time	Typically 3 hrs (note 2)
Sample access	Via removal of IVC
Cryogenic service interval	15,000 hrs

Note 1 : using an ITC503 to stabilise.

Note 2 : For low heat capacity sample and standard radiation shields. 3 hours is the time to recondense 3He charge and cool the 3He pot to <= 320 mK (if 3He initially at < 4K).

A complete HelioxAC-V system includes :

The cryostat unit including the integrated PTR and 3He refrigerator
The external compressor unit and gas lines for the PTR
The controlling electronics, leads and software

Options:

Wiring : Non-standard wiring to the helium-3 pot is available.
Cryostat tail : Special tails are available to fit a wide range of applications such as neutron scattering, low temperature detectors and optical applications.
Integration with a Cryofree magnet

Figure 2 below shows the basic working principle of the HelioxAC-V. The system employs a proprietary cryogenic cycle (US patent 678 2712, European patent 1387133 and Japanese patent application 2004163089). In phase 1 the 3He gas, which has previously been cryo-pumped by the cryogenic adsorbption pump (sorb), is regenertated from the sorb by opening the heat switch and heating the sorb. The 3He gas that is released is pre-cooled in the heat exchanger on the second stage of the PTR. Phase 1 is then completed by gas expansion into the 3He dump, causing liquefaction of the 3He into the pot. In phase 2, the sorb is cooled down through closing the heat switch and second stage of 3He expansion takes place. When the temperature of the sorb is reduced below 15 K it starts to pump vapour from the 3He pot and the temperature of the pot is reduced to base temperature through evaporation cooling.

HelioxAC-V Principle of operation

The HelioxAC-V is particularly suitable for the follow applications:

Material characterisation: studies of electrical, optical and thermal properties
Device characterisation: transport measurements, quantum device characterisation
Mass spectrometry: high sensitivity ion detection
Beam line applications: neutron scattering and X ray scattering
Astronomy: low energy photon detection
Metrology: voltage and current standards

HelioxAC-V with Cryofree magnet