A wide bore superconducting magnet for the Nicolet GC/MS system

Nicolet Instrument Corporation (NIC) is engaging in manufacturing high resolution Fourier transform mass spectrometer (FT-MS). The instrument called for a wide bore superconducting magnet to trap sample ions so as to generate cyclotron motion. The critical requirements consisted of 20 cm warm bore, 2 teslas central field, high field homogeneity in large volume, high field stability, high magnet reliability, simple charging/discharging procedures, low liquid helium and nitrogen boil-off rates and long liquids holding time. This paper presents the magnet design considerations, magnet construction experience and magnet test results.