A multiple purpose 7TNbTi split coil superconducting magnet system for Mössbauer spectroscopy and susceptibility measurements at various temperatures

The design, construction and test results of a compact NbTi coil system are described. The dimensions are: 198 mm outside diameter, 290 mm total length, 52 mm vertical central bore, 20 mm horizontal bore. The system consists of two assistant coils in addition to the main split pair. A total of ten wire sections is involved. Each part of the system can be separately charged or several other modes of operation are possible. So the main split pair can be used alone. In the screening mode operation one or both of the assistant coils keep the magnetic induction below 0.1 T, within certain ranges on and near the axis. Finally, in the gradient mode operation, the assistant coils are charged in the opposite direction so that a linear gradient field is superposed onto the main field. The versatility of this coil system implies the use of three independent superconducting switches.The coil system is mounted in a stainless steel dewar which has horizontal and vertical access for Mössbauer spectroscopy at various temperatures. An additional insert allows susceptibility measurements in the temperature range from 2 K up to 300 K. Details on the cryostat (designed by L. Bogner, F. Parak and W. Wiedemann) will be published later.