2D-Tomography of the Proton Beam in the Vacuum Insulated Tandem Accelerator

For the development of a promising method for the treatment of malignant tumors - boron neutron capture therapy - the accelerator-based epithermal neutrons source has been proposed and created in the Budker Institute of Nuclear Physics [1,2]. With different parameters of the proton beam - the energy and current of the beam, the parameters of the ion-optical system, the parameters of the ion source - the conditions for beam transportation change - its size, angular divergence, and position relative to the axis of the accelerator. For optimal conduction of the beam along the path, two-dimensional tomography of the beam can be used - using a cooled diaphragm with a diameter of several millimeters installed on a vacuum three-dimensional motion input, and a Faraday cup, fast chord measurements are carried out, on the basis of which the beam profile is restored. The beam profile obtained in this way is somewhat different from the profile obtained by measuring the phase portrait of the beam using a wire scanner [3]. The advantage of this method is a relatively short time to restore the profile, depending on the diameter of the cooled diaphragm hole.