OptiMag superconducting magnet systems — OM Series Standard OptiMag systems (OM series) feature magnetic fields of 6 to 9 T, sample tube diameters of 1.25 in to 1.75 in, a 12 L useful capacity helium reservoir, and bottom optical access along the vertical field axis. Standard configuration Standard configurations offer efficient operation with static hold times of ~60 h, and are available with field homogeneities of ±0.5% and ±0.1% over a 1 cm diameter sphere. Larger OM models are offered for higher magnetic fields (10 T to 12 T), larger sample tubes, longer helium hold times, and better field homogeneities (±0.01% to 0.001% over a 1 cm diameter sphere) are also available. As with the SuperVariMag systems, the OptiMag systems are offered with split pair coils along with double or triple coil configurations in various field strengths for horizontal field directions or rotating vector fields. Magnets with cancellation coils are also offered for Mössbauer spectroscopy vertical drive systems, where both the source and the absorber are top loaded into the sample space and cooled down to helium temperatures. When required, we also offer 9 T/11 T up to 12 T magnets with a Lambda point refrigerator (LPR) for operation at the higher field, with the reservoir at atmospheric pressure. The temperature of the sample can be varied between 1.5 K and 325 K, and optical access to the sample is along the direction of the magnetic field (straight solenoid magnets), from the bottom (or top) of the cryostat. The bottom window in the sample tube is typically an indium sealed sapphire window, or a Mylar window (for Mössbauer spectroscopy). A variety of strain relief mounted, indium sealed bottom windows from other window materials is available for transmission in various ranges of the electromagnetic spectrum. Customized systems can also be supplied with He-3 inserts for temperatures below 1.4 K.