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ISOCTA
Institute for Scientific Operations, Cryogenics & Technical Applications
[IMAGE: Tall cylindrical cryostat in a laboratory setting, surrounded by electronics racks, gas cylinders, and a helium recovery line running to the ceiling]
Figure 1: The 14 T superconducting solenoid in Building 5. The magnet dewar (blue, centre) is approximately 2.2 m in height. The variable-temperature insert is visible at the top of the cryostat. The magnet power supply rack (left) delivers up to 150 A. The gas-handling panel for helium recovery is at right.
Overview
Building 5 houses the Institute's 14 T superconducting solenoid, the
highest-field DC magnet on site. The magnet supports magneto-optical
measurements, magnetic materials characterisation, and detector development
across multiple Institute programmes. It was installed and commissioned in
September 2003.
Magnet Specifications
Parameter
Value
Central field (design)
14.0 T at 4.2 K
Winding technology
Nb3Sn (inner sections) + NbTi (outer sections)
Cold bore diameter
89 mm
Homogeneity
ΔB/B < 10−5 over 10 mm diameter spherical volume
Operating current
148 A at 14 T
Inductance
~42 H
Stored energy
~460 kJ at full field
Ramp time (0–14 T)
~45 minutes (controlled ramp)
Quench protection
Active quench detection with external dump resistor (0.5 Ω)
Manufacturer
Oxford Instruments (custom build)
Sample Environment
A variable-temperature insert (VTI) provides sample temperatures from
1.8 K to 400 K with ±0.01 K stability. The insert
accommodates:
Magneto-optical sample rod with fibre-coupled spectroscopy feedthrough
Rotating sample stage (±180°) for anisotropic measurements
Electrical transport puck (8 contacts, shielded twisted-pair wiring)
Custom inserts for specific experimental requirements
[IMAGE: Close-up of a polished metallic sample mount with optical fibre and lens assembly positioned above it inside a cryostat bore]
Figure 2: Magneto-optical Kerr effect measurement head mounted on the variable-temperature insert. The optical access port and polarisation optics are visible at the top of the assembly.
Current Research Applications
Magneto-optical Kerr effect (MOKE) magnetometry of rare-earth thin films and multilayer structures, with vector MOKE capability for in-plane and out-of-plane magnetisation components. [Magnetic Materials programme]
Critical current and irreversibility field measurements on high-temperature superconductor tapes and bulk samples for the superconducting bearing programme.
Calibration and characterisation of Hall sensors, magnetoresistive sensors, and pick-up coils for use in other Institute experiments.
Collaborative access for external users through the Nordic THz and Cryogenics networks. [Collaborations]
Access & Safety
Building 5 is a controlled-access facility. All magnet operators must
complete the high-field magnet safety induction
covering quench procedures, cryogenic hazards, and magnetic field exclusion
zones. The 5-gauss line extends approximately 3.5 m from the magnet axis
at full field; ferromagnetic objects and personal electronics are prohibited
within this zone.