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1
Content available remote Krakowskie cyklotrony
EN
A short account of three cyclotrons operating in Cracow during the last 50 years is presented.
EN
Operation mode simulation methods are based on selection of trim coil currents in the isochronous cyclotron for formation of the required magnetic field at a certain level of the main coil current. The traditional current selection method is based on finding a solution for all trim coils simultaneously. After setting the calculated operation mode, it is usually necessary to perform a control measurement of the magnetic field map and to repeat the calculation for a more accurate solution. The new current selection method is based on successively finding solutions for each particular trim coil. The trim coils are taken one by one in reverse order from the edge to the center of the isochronous cyclotron. The new operation mode simulation method is based on the new current selection method. The new method, as against the traditional one, includes iterative calculation of the kinetic energy at the extraction radius. A series of experiments on proton beam formation within the range of working acceleration radii at extraction energies from 32 to 59 MeV, which were carried out at the AIC144 multipurpose isochronous cyclotron (designed mainly for the eye melanoma treatment and production of radioisotopes) at the INP PAS (Kraków), showed that the new method makes unnecessary any control measurements of magnetic fields for getting the desired operation mode, which indicates a high accuracy of the calculation.
4
Content available AIC-144 cyclotron: present status
EN
The presented AIC-144 cyclotron was designed and constructed 20 years ago in the Institute of Nuclear Physics in Kraków (Poland). Later on it was modernized, after the decision of creating the Hadron Radiotherapy Centre in Kraków was taken by the government. At present, the cyclotron is capable to deliver beams of protons (with energy up to 60 MeV), deuterons (with energy up to 30 MeV) and a-particles (with energy up to 60 MeV). The magnetic structure and the RF system were modernized (a new HF generator with output power 120 kW and frequency range 10-27 MHz was installed; an RF cavity resonator was reconstructed to improve the Q-factor at the highest frequencies). The new PIG source and system of central diaphragms was built to improve beams quality on the first turns. The single lamella and multilamella probes were fully reconstructed. Special effort was put on a highly efficient extraction system. The precession method for particles extraction was chosen as the best one. All computer simulations and experimental runs were done in close cooperation with specialists from the Laboratory of Nuclear Problems JINR, Dubna. The extraction system consists of 2 electrostatic deflectors, 3 magnetic channels (passive) and 4 coils for shaping of the 1st harmonic. So far, the beam extraction experiments were carried out for the proton beams with the final energy of 35 MeV, 48 MeV and 60 MeV. For all these energies the efficiency of extraction was above 50%. A computer remote control of the main magnet power supply and of the 24 correction coils was installed and put into operation. In the last 3 years, the internal beams of protons and a-particles were used to produce radioisotopes like 11C, 57Co, 83-85Sr, 102Rh, 111In, 173-175Hf, 178-181W.
EN
This paper is a description of the computer simulation and the first experimental results on an AIC-144 isochronous cyclotron new extraction system. The cyclotron will be able to generate beams of protons, deuterons and alfa particles. One of the principal goals of the upgraded facility is to extract beams of protons and deuterons (proton energy 60 MeV, deuteron energy 30 MeV) for proton radiotherapy and for fast neutron beams. The precession method for particle extraction was chosen as the best one. It is the first time that the proton beam of energy 35 MeV has been extracted from the AIC-144 cyclotron with an efficiency of above 50%. More careful adjustment of the extraction system parameters (better control of the 1st harmonic of the magnetic field and the position of the deflectors) will permit an increase in the extraction efficiency to the design value of 70%.
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