Magnetic Sample Environments

In collaboration with the instruments the Sample Environment and Characterization group develops pulsed high magnetic field coils as well as constant field magnets. These devices will be available as a drop-in sample environment option for MID and SCS instruments.

The approach is to develop resistive copper coils that generate a high magnetic field (15 T) in a small bore (Φ10 mm). As resistive coils generate significant amounts of heat (up to 0.5 MW) the coil will be operated in millisecond-pulses that match the XFEL bunch-train. After one magnetic pulse a wait-time of ~10 seconds is needed before the coil has cooled sufficiently (in a LN2 bath) to allow another high magnetic field pulse.

In the bore of the miniature coils there will insert a sample-stick with helium-flow cryostat. Sample cooling from 10 - 300 K is possible. A horizontal split between coil halves will allow diffraction/scattering measurements.


The prototype components specific to the MID main vacuum chamber are illustrated here. 

Sample manipulation:

  • XYZ translation
  • Θ rotation (vertical axis)

Sample mounting:

  • Quick exchange via loadlock
  • Sample in higfh vacuum (HV)

Sample cooling:

  • 10 – 300 K via helium-flow cryostat

Constant field (DC) magnet

Constant low magnetic fields (up to 0.35 T) are required by SCS as an addition to their main Fast-Solid-Sample-Scanner (FSSS) sample environment. Our approach here was to develop a DC electromagnet for use in UHV that fits around the design of the FSSS. In addition the DC electromagnet can be moved in or out of operation by a linear translation stage. In order to maximize the constant magnetic field strength we cool the yoke internally via a recirculating water-chiller.
 

The illustration shows how the DC electromagnet (in green) integrates with the FSSS. The DC magnetic field is parallel to the X-ray beam and perpendicular to the square sample holder (5cm x 5cm). The bulky water-cooling lines include an extra rough-vacuum shield as a safety-barrier against potential water-leaks.