Magnets for the Candle Booster Synchrotron, Design and Prototyping

Magnet Pole Design CANDLE booster synchrotron magnetic lattice contains 48 dipoles of H-shape. Detailed magnetic and mechanical design of those magnets is performed within the framework of the project. In this report, the design considerations of the dipole magnet, including the magnetic field simulation is presented. The results of the numerical simulation are compared with the magnetic field measurements of the first prototype dipole magnet. Earlier versions of POISSON/SUPERFISH group of electromagnetic simulation codes contain pole design software utility MIRT [2], which now is considered as obsolete [3]. We employed the approach of the N. Marks et al [4] relaying on the some basic principles and a great deal of trial and error to determine magnet geometry in both transverse and longitudinal planes to meet the required field parameters. INTRODUCTION Table 1: Dipole magnet main parameters Third generation synchrotron radiation source CANDLE booster synchrotron will accelerate electrons from 100 MeV to 3 GeV for the injection into storage ring. 48 H-type parallel ends dipole magnets will provide required curvature of the beam orbit within the given energy range. Magnets will be 1.8 meters long and will be curved following beam trajectory in an attempt to keep sizes as minimal as possible [1]. Table 1 presents the main parameters of the magnet. Number of magnets 48 Magnet Length 1.8 m Magnet Type H-frame, curved Injected Beam Energy 100 MeV Beam Maximum Energy 3 GeV Bend Angle 0.1309 radians Inter-Pole Gap 30 mm Maximum Field 0.723 Tesla Good Field Region Width 30 mm Field Uniformity in Good Field Region ∆B/B ≤ 5×10 Curvature Radius 13.75 m Lamination Width 0.5 mm Lamination Weight 0.066 kg Number of Laminations per Core ~ 6980 Stacking Factor 0.98 Assembled Core weight 560 kg Chamfer Depth 27 mm, (45) Material Russian 2213 steel Number of Turns per Pole 6 AmperesTurns 8684 Current max. /min. 1447A / 50 A Ramping Repetition Rate 2 Hz Conductor Size (width×height, hole diameter) 20.5×14 mm, ∅=10 mm Conductor Area 203.1 mm Resistivity 0.0178 mΩ×mm/m Current Density (max.) 7.4 A/mm Conductor Length per Magnet 48.3 m Coils Weight 2 × 48 kg Magnet Resistance 4.23 mΩ Magnet Inductance 0.99 mH Voltage Drop per Magnet (max.) 16 V Power per magnet (max.) 9.5 kW SIMULATIONS AND DESIGN The parameters defining design are listed in the Table1. With the distance between booster and storage ring minimally being 2.8 m, stray fields from booster magnets may influence the storage ring beam. H-type shape closed yoke magnets are a good choice to minimize those stray fields. To allow access to the pole area and to mount the coils, the magnet yoke is divided at the horizontal median plane. Figure 1: The plot of field-lines of the CANDLE booster dipole magnet. _________________ [email protected] Proceedings of EPAC 2004, Lucerne, Switzerland