| Paper |
Title |
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| WEPKF003 |
Design of the End Magnets for the IFUSP Main Microtron
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1591 |
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- M.L. Lopes, A.A. Malafronte, M.N. Martins, J. Takahashi
USP/LAL, Bairro Butantan
- K.-H. Kaiser
IKP, Mainz
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The Instituto de Física da Universidade de São Paulo (IFUSP) is building a two-stage 31 MeV continuous wave (cw) racetrack microtron. In this work we describe the characteristics of the end magnets for the IFUSP main microtron. The magnets are part of the main acceleration stage, which raises the energy from 4.9 to 31 MeV. We are studying the possibility of increasing the energy up to 38 MeV, so the magnets should have approximately 2x1 m2 region of useful field. The dipoles have a 0.1410 T magnetic field and 1 part in 1000 homogeneity without correcting devices. Using a 2D magnetic field code (FEMM), we illustrate the use of homogenizing gaps with different forms and non parallel pole faces to achieve the necessary homogeneity. The use of clamps to produce reverse fields to reduce the vertical defocusing strength on the beam is also described. In order to calculate the beam trajectories and to evaluate the magnetic field homogeneity within the useful region, a 3D magnetic field software (TOSCA) was used.
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| WEPKF031 |
Magnetic Field Correction of the Bending Magnets of the 1.5 GeV HDSM
|
1669 |
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- F. Hagenbuck, P. Jennewein, K.-H. Kaiser
IKP, Mainz
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Beam dynamics of the Harmonic Double Sided Microtron (HDSM), the fourth stage of MAMI, require a very precise magnetic field in the inhomogeneous bending magnets. By measuring the vertical field component By in and on both sides of the midplane, the complete set of field components Bx, By, Bz was determined in the whole gap. Starting from this the asymmetric pole surface current distribution necessary to correct both symmetric and antisymmetric field errors was calculated. However, tracking calculations showed that the influence of skewed field components on the beam deflection are negligible, so that symmetric field corrections are sufficient. Nevertheless, in order to demonstrate the functioning, a set of asymmetric correction coils was built and successfully tested. The symmetric coils are designed to reduce field errors below 2*10-4. Deflection errors in the fringe field region near the magnet corners, which cannot be corrected by surface currents, will be compensated by vertical iron shims in combination with small dipoles on each beam pipe.
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