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Description
In the CSNS-II, the energy of the H¯ ion beam from the linear accelerator will be increased from the current 80 MeV to over 300 MeV. Consequently, the integrated magnetic field strength of all magnets in the RCS injection system will be raised by 2 to 2.5 times compared to the requirements during the CSNS phase. To achieve the complex functions of the injection system within a constrained space, various types of special magnets have been introduced. Due to the change of the injection point location, the angle at which the waste beam is drawn out is very small. To minimize the influence of the leakage field from the septum magnet on the circulating beam and to reduce the local peak power and temperature on the target of the injection dump station, a horizontal pulsed septum magnet is employed for the extraction of the waste beam. This magnet utilizes six types of metallic materials, with the core made of 0.15 mm thick silicon steel sheets, end plates made of stainless steel, coils made of oxygen-free copper plates, leakage field shielding material made of Permalloy, vacuum box material within the magnet gap made of Inconel 625, and auxiliary shielding material outside the circulating beam pipe made of 0.5 mm thick silicon steel sheets. The pulse duration is 1.5 ms, and the maximum current is 5000 A. This paper will first provide an overview of previous research on pulsed septum magnets, followed by a presentation of the design analysis and magnetic field measurement results of the out-of-vacuum Direct-drive pulsed septum magnet in the CSNS-II RCS injection system, including simulations of the eddy current effects of various materials and methods of pulse magnetic field measurement and data analysis.
