Skip to main content
National MagLab logo

The MagLab is funded by the National Science Foundation and the State of Florida.

25 Tesla, 32 mm Split Helix Magnet (Cell 5)

25 Tesla 32mm Split Helix Magnet Cell 5

The Split-Florida Helix (SFH) magnet is the first modern powered magnet optimized for advanced optical spectroscopy techniques requiring wide, free-space access to samples.

The SFH magnet uses similar technology as in other Florida-Bitter designs, except that the conducting helix in the region around the mid-plane is replaced with a solid conductor having four wide optical ports evenly spaced around the perimeter and milled for the largest solid angle collection volume. The magnet features four identical ports radially arranged at 90° intervals around the mid-plane of the 32 mm vertical bore. A cutaway view (see below) of the magnet shows two of these ports, each providing ± 22.5° free-space angular access (in the horizontal plane perpendicular to B) and ± 5.7° access (in a vertical plane parallel to B) to the center of the vertical magnet bore. Two ports are equipped with full size gate valves allowing for convenient replacement of optical windows. The magnetic field is 25 T at the window plane.

The SFH magnet is surrounded by three non-magnetic optical tables, which also support a platform positioned above the magnet. For low-temperature experiments, a LHe4 custom designed cryostat (sample in vacuum) can be installed on the top platform, which provides vibration isolation of the cryostat from the water-cooled resistive magnet. The geometry of the SFH ports and the arrangement of the optical tables allow unprecedented flexibility in the choice of scattering geometries for high-field experiments, and placement of optical and positioning equipment. Various technical aspects of the new magneto-optics setups will be presented.



  • Maximum Field: 25 tesla
  • Bore Diameter: 32 mm
  • Homogeneity: 5500 ppm
  • Number of input and output leads possible: 12
  • Frequency: 0-1 PHz
  • Temperature Range: 10-300K
  • Power: 27 MW
  • Open for users who would pay for magnet time: Yes


Loading Publications


Credit: National MagLab

Making the Split Bore Magnet

Staff Contact

For more information, please contact

Last modified on 26 December 2022

search magnet icon

Find the Perfect Magnet
for your Research

Search our magnets by field strength, bore size, and even technique.