CARTOGRAPHIE MAGNETIQUE DES QUADRIPOLES DES SPECTROMETRES A HAUTE RESOLUTION DU THOMAS JEFFERSON NATIONAL ACCELERATOR LABORATORY, HALL A. (Le Projet Q.M.M : Quadrupole Magnetic Measurement)

Abstract : This thesis describes the magnetic measurements that have been performed on the superconducting quadrupoles of the High Resolution Spectrometers of TJNAF, Hall A (USA), which are deisgned to measure particle momentum up to 4 GeV/c with a $\sigma p/p= 10-4 resolution. The mapping method is based on rotating coil technique, the originality being a segmentation of the probe along the quad axis. Together with an accurate magnet modelisation, the measurement of flux variations through the set of rotating coils allows to determine the magnetic field at each point. We use the 3D field formalism, i.e. the Fourier-Bessel expansion of the field obtained by solving the Lapace equation. We describe the QMM method and then the apparatus consisting in two probes of length 1.6 m and 3.2 m built to map the three quadrupoles Q1, Q2, Q3. Data processing uses Fourier analysis. The mapping of the Electron Arm took place on site in 1996. A first set of results concerns integral measurements, including the properties of excitation cycle of the magnets (saturation and hysteresis). A second set of results in terms of local field yields the 3D field maps of the quadrupoles. After having applied corrections to the data, we obtain a local field accuracy of 5 Gauss on each component, i.e. an uncertainty of 5.10-4 relative to the quadrupole central field. We use SNAKE raytracing code with the implementation of QMM field maps and obtain preliminary results on HRS optics.
Document type :
Theses
Other. Université Blaise Pascal - Clermont-Ferrand II, 1997. French


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Submitted on : Friday, December 17, 2004 - 1:34:24 PM
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  • HAL Id : tel-00007806, version 1

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Gilles QUEMENER. CARTOGRAPHIE MAGNETIQUE DES QUADRIPOLES DES SPECTROMETRES A HAUTE RESOLUTION DU THOMAS JEFFERSON NATIONAL ACCELERATOR LABORATORY, HALL A. (Le Projet Q.M.M : Quadrupole Magnetic Measurement). Other. Université Blaise Pascal - Clermont-Ferrand II, 1997. French. <tel-00007806>

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