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Malafronte, A.A.

Paper Title Page
FPAT044 Low Cost Magnetic Field Controller 2833
 
  • A.A. Malafronte, M.N. Martins
    USP/LAL, Bairro Butantan
 
  Funding: Fundacao de Amparo a Pesquisa do Estado de Sao Paulo-FAPESP, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico-CNPq.

The Physics Institute of the University of São Paulo (IFUSP) is building a continuous wave (cw) racetrack microtron. This machine has several dipole magnets, like the first and second stage recirculators, and a number of smaller ones in the transport line. These magnets must produce very stable magnetic fields to allow the beam to recirculate along very precise orbits and paths. Furthermore, the fields must be reproducible with great accuracy to allow an easier setup of the machine, though the effects of hysteresis tend to jeopardize the reproducibility. If the magnetic field is chosen by setting the current in the coils, temperature effects over the magnet and power supply tend to change the field. This work describes an inexpensive magnetic field controller that allows a direct measure of the magnetic field through an Hall probe. It includes a microcontroller running a feedback algorithm to control the power supply, in order to keep the field stable and reproducible. The controller can also execute algorithms to ramp up and down the power supply in a specific mode, in order to reduce hysteresis.