American Magnetics CRYOGEN FREE SUPERCONDUCTING MAGNET SYSTEMS User Manual

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.

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.