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CRYOGEN FREE SUPERCONDUCTING MAGNET SYSTEMS
Cryogen-free superconducting magnets have become increasingly popular in research and industry due to their ease and simplicity of operation as compared to traditional liquid helium cooled
magnet systems. These magnets are manufactured in a variety of confi gurations and sizes to
accommodate requirements of most imaginative scientists or engineers. Cryogen free magnet
systems use a closed cycle helium refrigerator to cool the cryogenic assemblies to temperatures
close to 4K. In certain confi gurations the magnet is conductively cooled in a vacuum whereas
some geometries use traditional LHe cooling with a cryocooler to recondense liquid Helium;
thereby resulting in near zero loss system (ReCon TM ). Based on customer’s experimental requirements either a Gifford-McMahon or a pulse tube cryocooler is used. Some of the most
widely used types of cryogen free magnet systems are listed and discussed below.
Room Temperature Bore (RTB) Solenoid Systems (Vertical or Horizontal geometry)•
RTB Radial Access Magnet Systems (Magneto-Optic systems)•
TM
RTB MAxes •
Multi-axis Magnet systems
Variable Field Variable Temperature (VFVT) magnet systems•
ReCon •
TM
style systems
Room Temperature Bore Solenoid Systems
These style systems are available in wide
range of bore sizes and fi elds up to 15T and
are designed in both horizontal and vertical
geometries. The thermal mass is cooled by
a Gifford-McMahon or a pulse tube cryocooler depending on the individual application. Pulse tube based cryocooled systems
are recommended for applications that might
have concerns with vibrations, however they
have higher initial costs but lower long
term maintenance costs. In case of pulse tube
confi guration, it is possible to reduce vibration
levels even further by adding bellows assembly and positioning motor remotely. Some of
the most common applications include material processing, beam line studies or use with
existing sample inserts . Materials processing customers have found this geometry very
suitable for annealing samples in presence of
Pulse tube based RT bore system
magnetic fi eld.
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Room Temperature Bore Radial Access Magnet System
Magnet system mounted on Huber Goniometer
The radial access port magnets allow perpendicular access to the magnetic fi eld. These types
of magnet systems are ideally suited for performing angular dependent studies on samples
in presence of magnetic fi eld. Systems with
vacuum bore are ideal for spectroscopy studies.
Spectroscopy is at the forefront in investigating
mechanisms driving magnetic properties. The
compact nature of cryogen free magnet systems
has made it easier for positioning them in beam
lines or optical benches and they are typically
mounted on diffractometers in use at Synchrotron or Neutron diffraction facilities around the
world. One of the systems shown here is used
at ESRF and it has been mounted in both horizontal and vertical fi eld confi gurations. Such
geometry is ideal for use with powder x-ray
diffractometers.
Radial access RTB magnet system
Radial access cryogen free magnet systems available up to 10T •
RTB MAxes systems available in 2 or 3-axis geometries•
Actively shielded magnet systems available for spectroscopy applications including •
Mossbauer studies
Custom designs available for x-ray & neutron diffraction•
Radial access magnets are made of NbTi / Nb3Sn with wide angular access for accessing the
transmitted or refl ected beams. These systems
are available for fi elds up to 10T with active
shielding. An extension of these are our popular
TM
CF MAxes
systems. These use combination
of two or more split coils to produce 2-axis or
3-axis geometries. An OptiMAxes TM uses 3
conduction cooled split coils to provide optical
access in two planes. CF MAxes TM magnets
have also been produced for our OEM’s who
have integrated them with Cryogen free dilution refrigerators.
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Variable Field Variable T emperatur e (VFVT)
Cryogen Free Magnet System
VFVT system is one of the most desired cryogen free magnet
system for use in material science and condensed matter physics laboratory. The system uses a single cryocooler (GiffordMcMahon or pulse tube) to cool the sample space and superconducting magnet, thereby eliminating need for liquid helium
and associated expensive recovery systems. Custom designed
confi gurations are available for exotic experimental needs.
VFVT Radial access magnet system
Low vibration VFVT system
with remote motor option
Available in vertical fi elds up to 14T.•
Available in horizontal fi elds up to 10T •
30 mm sample space with 2K to 325K operation using He exchange gas•
Systems available with customer defi ned window material for spectroscopy studies•
CF MAxes TM systems available with vector fi eld up to 5T•
CF OptiMAxes TM systems available with vector fi elds up to 2T•
Unique dual-axis confi guration available for positioning sample in vertical or hori-•
zontal fi eld confi guration
Turnkey system with software controlled VFVT environment•
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200mm RTB ReCon system
ReCon TM Magnet Systems
Based on heat load and size of the superconducting magnet
either a dry conduction cooled or ReCon
etry is recommended. ReCon
TM
style magnet systems use
cooling power of a closed cycle 4K cryocooler to recondense gaseous helium back into the liquid Dewar. The
evaporating gas is liquefied in a thermodynamically effective manner and the cryocooler is strategically located
in the Dewar. The first stage of the cryocooler is used to
cool the shields of the Dewar thereby eliminating the need
for any liquid Nitrogen. ReCon
TM
magnet systems offer
combined benefits of traditional LHe systems with near
zero helium boil-off. These style systems are ideally suited
for retrofitting existing magnets and sample inserts into
a re-engineered Dewar with a suitable gas handling system. Pulse tube cryocoolers are ideal for applications that
desire lower vibrations.
TM
style geom-
ReCon •
TM
solenoid systems available in vertical or horizontal geometries with
fi elds up to 16T and wide bore sizes
ReCon Maxes •
ReCon OptiMAxes •
ReCon •
TM
TM
systems are available with vector fi elds up to 6T
TM
systems are available in 2 or 3-axis geometries
split coil systems available in optical and non-optical confi gurations
with fi elds up to 10T
ReCon •
TM
systems with customized gas handling system is available with 1.5K/
He3 insert or with a dilution refrigerator
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