C-1 Magnet Design and Measurements
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SUPAG03 Challenges in Extracting Pseudo-Multipoles From Magnetic Measurements 87
  • S. Russenschuck, G. Caiafa, L. Fiscarelli, M. Liebsch, C. Petrone, P. Rogacki
    CERN, Geneva, Switzerland
  Extracting the coefficients of Fourier-Bessel series, known as pseudo-multipoles or generalized gradients, from magnetic measurements of accelerator magnets involves technical and mathematical challenges. First, a novel design of a short, rotating-coil magnetometer is required that does not intercept any axial field component of the magnet. Moreover, displacing short magnetometers, step-by-step along the magnet axis, yields a convolution of the local multipole field errors and the sensitivity (test function) of the induction coil. The deconvolution must then content with the low signal-to-noise ratio of the measurands, which are integrated voltages corresponding to spatial flux distributions. Finally, the compensation schemes, as implemented on long coils used for measuring the integrated field harmonics, cannot be applied to short magnetometers. All this requires careful design of experiment to derive the optimal length of the induction coil, the step size of the scan, and the highest order of pseudo-multipoles in the field reconstruction. This paper presents the theory of the measurement method, the data acquisition and deconvolution, and the design and production of a saddle-shaped, rotating-coil magnetometer.  
slides icon Slides SUPAG03 [4.548 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-SUPAG03  
About • paper received ※ 18 October 2018       paper accepted ※ 27 January 2019       issue date ※ 26 January 2019  
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SUPAG10 Design Study of a Fast Kicker Magnet Applied to the Beamline of a Proton Therapy Facility 110
  • W.J. Han
    Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China
  • X. Liu, B. Qin
    HUST, Wuhan, People’s Republic of China
  Funding: Huazhong University Of Science And Technology
A proton therapy facility based on an isochronous superconducting cyclotron is under development in HUST (Huazhong University of Science and Technol-ogy). A fast kicker magnet will be installed in the up-stream of the degrader to perform the beam switch function by kicking the proton beam to the down-stream beam stop. The rising and falling time of the kicker is about 100us, and the maximum repetition rate is 500Hz. This paper introduces simulation and opti-mization of the eddy current and dynamic magnetic field of the fast kicker, by using FEM code OPERA-3D. For kicker materials, laminated steel and soft ferrite are compared and the MnZn ferrite is chosen. Design-ing considerations includes the eddy current effect, field hysteresis, and mechanical structure of the kicker will also be introduced.
slides icon Slides SUPAG10 [1.184 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-SUPAG10  
About • paper received ※ 19 October 2018       paper accepted ※ 04 December 2018       issue date ※ 26 January 2019  
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WEPAF01 A Compact Permanent Magnet Spectrometer for CILEX 320
  • M. Khojoyan, A. Cauchois, J. Prudent, A. Specka
    LLR, Palaiseau, France
  Laser Wakefield acceleration experiments make exten- sive use of small permanent magnets or magnet assemblies for analyzing and focusing electron beams produced in plasma accelerators. Besides being compact, these magnets have to have a large angular acceptance for the divergent laser and electron beams which imposes constraint of the gap size. We will present the optimized design and charac- terization of a 100 mm long, 2.1 Tesla permanent magnet dipole. Furthermore, we will present the performance of such a magnet as a spectrometer in the CILEX/APOLLON 10PW laser facility in France.  
slides icon Slides WEPAF01 [6.898 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-WEPAF01  
About • paper received ※ 15 October 2018       paper accepted ※ 28 January 2019       issue date ※ 26 January 2019  
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