GB932566A - Improvements in variable polarization saturable magnetic circuits - Google Patents

Abstract

932,566. Particle accelerators. COMMISSARIAT A L'ENERGIE ATOMIQUE. June 15, 1960 [June 20, 1959], No. 21063/60. Class 39 (1). [Also in Groups XXXV and XL (b)] A variable polarization saturable magnetic circuit which may be used in tuning the resonant cavity of a particle accelerator comprises a closed magnetic core of uniform crosssection having a polarizing coil surrounding a part of its circumference, an open magnetic flux " distributer " being held against the core along the part surrounded by the coil to improve the uniformity of distribution of the magnetic flux along the core. Figs. 3 and 6 show the magnetic circuit 1, 3 used in a high-frequency self-inductance device 4 associated with an inductive cavity used to accelerate protons around a closed trajectory in the annular vacuum chamber 5 of a synchrotron. The accelerating potential difference at the electrodes 6, 7 on each side of the gap 8 is obtained from a variably tuned resonant circuit consisting of capacitor 9 and the device 4, the self inductance of which is varied by varying the polarizing current in windings 2 surrounding cores 1. The forty ferrite magnetic core frames 1 (Fig. 6), are housed between the outer and inner two coaxial lines, the outer being of copper covered steel plates 4a and 11 and the inner of stainless steel tubes 4b which form the chamber 5. The core section inside the watercooled tubular polarizing windings 2 is increased by the addition of laminated bars 3 made of steel strips held together by " Araldite " (Registered Trade Mark). An insulating joint 12 of the same material may close the accelerator gap in tube 5. The core frames are arranged in four sets of five pairs separated by cooling gaps 17 and are formed of ferrite bars held together by clamping means (Fig. 5, not shown). The two symmetrically arranged polarizing windings 2 are twisted in the form of an 8 to prevent coupling of the high frequency of the accelerating field with the lowfrequency polarizing circuit. The polarizing circuit may be provided with a filtering device outside the cavity.