Custom magnet systems

Helium recondensing high field split pair magnet for neutron scattering

A high field helium recondensing split pair
magnet system for neutron scattering

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At Oxford Instruments we are proud to have been part of the success of many very challenging magnet projects around the world, using our world-leading position in superconducting magnet and cryogenic design, project management, manufacture and customer support. Our engineering and manufacturing team applies their expertise on many such custom-engineered projects each year, to deliver a magnet system which meets our customer's needs and budget.

The superconducting magnets systems which we have provided to customers range across a myriad of applications, including: neutron scattering, x-ray diffraction, optical spectroscopy, μSR, UHV environments, solid state NMR, ESR/EPR, levitation, gyrotrons, SPM and AFM environments, and materials processing.

See related article on aspects of design for Superconducting magnets for neutron scattering in the Links panel.

Please contact us to discuss your specific requirements.

Recent systems
Images
Example - 3/3/3 vector rotate
Example - 3 T μSR magnet
Example - Recondensing 2.2 K magnet

Recently delivered custom-engineered superconducting magnet systems include:

Magnet system/application	Country	Delivery date
Recondensing 6/2/2 T vector rotate magnet (6 T solenoid / 2 T split pair / 2 T split pair) with VTI, using a NEW design of recondensing dewar. The system is fully recondensing (true zero boiloff) with spare cooling capacity in static conditions, and is also fitted with special HTS current lead sections so that the system remains recondensing even with with current in leads.	Czech Republic	October 2011
3/3 T (2 x 3 T split pair, field directions in z- and x-axis) vector rotate magnet system with x- and y-axis optical access, VTI sample loading in z-axis, based upon our well-known Spectromag® cryostat. See CAD model on Images tab	Poland	October 2011
Recondensing 17 T @ 4.2 K, 18 T @ 2.2 K magnet system with VTI, using a NEW design of recondensing dewar. in sock. The system is fully recondensing (true zero boiloff) with spare cooling capacity in static conditions.	Switzerland	September 2011
5/1/1 T (3 x split pair, 5 T in z-axis) vector rotate magnet system with x- and y-axis optical access, VTI sample loading in z-axis, based upon our well-known Spectromag® cryostat.	China	May 2011
Special wide-bore solenoid magnet system for high temperature superconductor (HTS) coil testing and development Superconducting magnet with specially reinforced coil structure to withstand forces with HTS insert coils in place 8.5 T at 4.2 K, 10 T at 2.2 K Magnet cold bore 147 mm diameter	USA	February 2011
High homogeneity split pair magnet system for muon spin resonance (μSR) spectroscopy 8 T @ 4.2 K and 9.5 T @ 2.2 K Independent shims and custom-written software to maintain homogeneity across wide field range Recondensing system including recondensation of LPF exhaust See Example tab on this page	Switzerland	February 2011
Kelvinox®HA dilution refrigerator/magnet system with two cancelled 9 T solenoids with minimum coupling between both magnets, for nuclear demagnetisation refrigeration. See CAD model on Images tab	UK	January 2011
15 T high homogeneity (1 in 10^4), high persistence (10 ppm/h) magnet system with 40 mm sample space VTI, in low loss cryostat	Japan	November 2010
Dual mode, horizontal field split pair magnet system for neutron scattering 6.8 T in symmetric mode 6.2 T in asymmetric mode Simple change-over by current lead selection Neutron access in the field direction of 45° solid angle onto a 15 mm sample See CAD model on Images tab	Switzerland	July 2010
12 T high homogeneity (1 in10^5), high persistence magnet system with 62 mm sample space VTI, in low loss cryostat	China	July 2010
12 T high homogeneity (1 in10^5), high persistence magnet system with 62 mm sample space VTI, in low loss cryostat	Croatia	May 2010
8/10 T high homogeneity solenoid magnet system with axial optical access and special VTI for Mössbauer spectroscopy	Japan	May 2010
12.5 T AS (actively shielded) high homogeneity solenoid magnet system for ESR See magnet photo on Images tab	USA	March 2010
8 T split pair X-ray diffraction magnet system	India	October 2009
6 T high homogeneity split pair magnet system for ESR (electron spin resonance)	Japan	September 2009
3 x 3 T split pair vector rotate magnet system with x- and y-axis optical access See Example tab on this page More details can be found in our Magnet Project Library	Germany	September 2009
Recondensing 10 T asymmetric split pair magnet system for neutron scattering Vertical angle ± 5° onto a 30 mm length x 38 mm diameter cylindrical sample Horizontal access: 2 x 130° angles	France	June 2009
3 T high homogeneity split pair magnet system for muon spin resonance (μSR) spectroscopy See Example tab on this page More details can be found in our Magnet Project Library	Canada	June 2009
6 T high homogeneity split pair magnet system with independent shims and sweep coil for ESR (electron spin resonance)	UK	June 2009
Recondensing wide-angle 9 T (at 4.2 K) split pair magnet system for neutron scattering Wide-angle vertical sample access: ± 15° measured from 25 mm sample height Wide-angle horizontal access: two ± 45° angles separated by 180°, plus additional horizontal access at 90° to the ± 45° openings	UK	April 2009
Recondensing 13.7 T (at 4.2 K) split pair magnet system for neutron scattering Vertical angle -5º/+10º onto a 10 mm length x 10 mm diameter cylindrical sample, with 20 mm minimum vertical gap Horizontal access: 340° angles with single 20° dark angle Cadmium plating to inner (beam path) magnet former faces to reduce unwanted reflections	UK	March 2009

Please contact us to enquire about any of these or similar designs, or to discuss your own specific needs.


3/3 (2 x 3 T split pair, field directions in z- and x-axis) vector rotate magnet system	Dual mode, horizontal field split pair magnet system for neutron scattering

Actively Shielded high homogeneity 12.5 T magnet	Kelvinox®HA dilution refrigerator/magnet system with two cancelled 9 T solenoids for nuclear demagnetisation refrigeration

3/3/3 Tesla vector rotate magnet system with optical access

3/3/3 Tesla vector rotate magnet system with optical access

This custom-designed vector rotate magnet system differs from the usual vector rotate configuration by featuring three orthogonal split pair magnet coils, rather than the more conventional solenoid with one or two orthogonal split pair coil sets. This is in order to offer straight-through optical access in the horizontal (x and y) axes, with perpendicular sample access and loading in the vertical z axis into a 1.5‑300 K variable temperature insert (VTI).

Despite its apparently ‘low’ field, the magnet design is not trivial, due to the large twisting forces set up between the coils in their different vector combinations. Careful three-dimensional stress analysis enabled a successful design in which the magnet can be run to any vector up to 3 Tesla magnitude within a complete 360º sphere.

To fit the magnets in a compact arrangement, the z-, y- and x-axis coil pairs are nested inside each other as shown below. Each pair of coils is fitted with its own persistent mode switch.

The cryostat is a low-loss Oxford Instruments design for optical and beamline applications. To reduce the number of optical elements in the beam path, the radiation shield has no windows but is fitted with re-entrant bore tubes to reduce the radiative heat load. This cryostat design can also be supplied as a zero-boiloff helium recondensing system.

More details can be found in our Magnet Project Library
To find out more, please email us at nanoscience@oxinst.com

3 Tesla high homogeneity magnet system for muon resonance (μSR) spectroscopy

3 Tesla high homogeneity magnet system for muon resonance spectroscopy

This magnet system was supplied in 2009 for muon spin resonance spectroscopy on a customer’s new and upgraded beamlines, and consists of a high homogeneity, low drift rate 3 T split pair magnet mounted within the tail set of a low loss cryostat.

The magnet incorporates independent shim coils to provide a high level of homogeneity correction. As it is important in this application to remove remanent field effects, ‘zero field’ coils are located within the magnet.

The cryostat is based on a standard Oxford Instruments NMR-type low loss cryostat, with modifications to suit the specific requirements of the customer's system specification, and provides liquid helium hold time of > 14 days. Ambient temperature access is provided along the two orthogonal directions in the horizontal plane. Vacuum sealing faces and mounting holes for sample cryostats and are provided on the bore tube end flanges for integration with the beamline and detectors. 3 Tesla high homogeneity magnet

A key success of this magnet system was in achieving the extremely tight clearance and precise alignment requirements of the magnet coils (right) within the cryostat tails. By comparing magnetic field plots from either end of the bore, the angular deviation of the flux density vector relative to the bore axis was calculated as only < 0.03º, compared to a specification requirement of < 0.2º – an excellent achievement.

Muon spin resonance (μSR) spectroscopy

The broadest application of μSR spectroscopy is as a magnetic probe with which to examine structural and dynamic processes in bulk materials on an atomic scale, providing a powerful technique to gain a deeper understanding of magnetic materials, semiconductors and superconductors. Beams of positive muons are created with aligned spins, which precess around the local magnetic fields within the material that the beam is fired into it. The muons decay into positrons which are typically ejected in the same direction as the muon spin. By measuring the directions in which the positrons are emitted, the μSR spectroscopist can investigate how the internal magnetic fields of the sample materials have influenced the muon spins.

More details can be found in our Magnet Project Library

To find out more, please email us at nanoscience@oxinst.com

High homogeneity split pair magnet system for muon spin resonance (μSR) spectroscopy

This magnet system provides a high homogeneity, specific field profile in a horizontal room temperature bore tube, at 8 T (4.2 K) and 9.5 T (2.2 K Recondensing 2.2 K magnet system for muon spin resonance ). Field alignment is precisely made between the magnetic and mechanical axes within the bore.

A particular challenge of this magnet system was to be able to maintain homogeneity from very low fields right up to 9.5 T. This was achieved using independent shims in conjuction with custom-written software to set the shim currents automatically from the magnetic field being set by the magnet power supply.

To achieve the upper field without resorting to Nb3Sn conductors, a lambda point refrigerator (LPF) system was used. Since the main liquid helium bath is maintained at 4.2 K and atmospheric pressure, a pulse tube (PTR) recondensing system could be fitted to give zero liquid helium consumption during static conditions. Further, this removes the need for users to enter the beamline area to refill liquid nitrogen since the PTR cools the radiation shields.

The recondensing system has sufficient power to recirculate the LPF exhaust back into the magnet system, and reliquefy it, providing full recondensation with the magnet persistent at 2.2 K.

To find out more, please email us at nanoscience@oxinst.com

Please click here if you would like additional information or assistance

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Downloads And Links

Aspects of superconducting magnet design for neutron scattering sample environments

Click here to download the free article from the IOP Science, Journal of Physics:conference series by F J Brown 2010 J. Phys.: Conf. Ser. 251 012093 http://iopscience.iop.org/page/copyright_notice