Mechanical system for superconducting cyclotron magnetic field measurement

An elaborate system has been developed to measure the magnetic field at the median plane of main magnet of K500 superconducting cyclotron under construction at VECC. Accurate measurement of the magnetic field in the superconducting cyclotron is required for detailed beam dynamics calculations for efficient acceleration and extraction. A scheme for detailed mapping has been planned. This involves measurement of the absolute value of field at the center of median plane of the cyclotron using a D2O NMR probe. A search coil is driven radially through the centre up to the extraction radius of the cyclotron. The moving search coil passing across spatially varying magnetic field generates a voltage proportional to the rate of change of magnetic flux through the coil. The search coil voltage is processed by a complex integrator to obtain the relative difference of magnetic field at points with respect to the center. The magnetic field and its positional information is recorded online for detailed beam dynamic studies