Actively shielded 8 tesla magnet for FT-ICR mass spectrometry

Intermagnetics successfully delivered an 8 tesla magnet for Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR). This high field magnet is used by Lilly Research Laboratories for routine high-resolution and exact mass analysis of higher molecular weight biopharmaceutical and biotechnology products such as proteins, DNA, etc. The system includes a NbTi magnet with high homogeneity and persistence, and a cryocooler refrigerated cryostat with a low He boil off and a long refill interval. The magnet system incorporates many of the user-friendly features of Intermagnetics' line of Magnet Resonance Imaging (MRI) magnets including a compact self-shielded configuration, high uniformity, nitrogen-free cryogenic technology, cold-shippable for fast setup on site, and other features. The 100 cm long magnet has a 152 mm diameter horizontal room temperature bore. The achieved uniformity is better than 6 ppm peak-to-peak in a 50 mm diameter, 50 mm long cylinder. The guaranteed magnet persistence is better than 50 ppb/hour. The 5 gauss line is located 1.4 m radially and 2.4 m axially from the magnet iso-center, resulting in a stray field that is even closer to the cryostat than in lower field unshielded FT-ICR magnets. Liquid helium refill interval is 6 months or longer. Due to the reduced stray field, compactness and relatively lightweight design, this magnet may be used to replace lower field, unshielded magnets in mass spectrometry facilities.