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| MOPLS100 | CLIC Final Focus Studies | CLIC, luminosity, sextupole, quadrupole | 792 | ||
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The design of the CLIC final focus system is based on the local compensation scheme proposed by P. Raimondi and A. Seryi. However, there exist important chromatic aberrations that deteriorate the performance of the system. This paper studies the optimization of the final focus based on the computation of the high orders of these aberrations using MAD-X and PTC. The use of octupole doublets to reduce the size of the halo in the locations with aperture limitations is also discussed.
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| TUPLS054 | The Isochronous Mode of the Collector Ring | emittance, ion, closed-orbit, quadrupole | 1618 | ||
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The isochronous mode of a storage ring is a special ion-optical setting in which the revolution time of circulating ions of one species does not depend on their velocity spread. In this mode the ring can be used for mass measurement of exotic nuclei. The Collector Ring (CR) [1] of the FAIR project [2] will operate in such mode as time-of-flight spectrometer for short-lived exotic nuclei (T1/2 > 20 μs) produced and selected in flight with the Super-FRS fragment separator [3]. This technique has been developed at the ESR [4]. The dependence of the revolution time in the isochronous ring from its transverse acceptance, the closed orbit distortion, and nonlinear imperfection of the magnet field was investigated analytically and with a Monte-Carlo simulation. The corresponding results will be presented.
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References: [1] A. Dolinskii et. al., GSI Annual Report, 2004 [2] W. Henning, Nucl. Phys. A721 (2003)211c [3] H. Geissel, et. al., Nucl. Instr. Meth. B204 (2003)71 [4] M. Hausmann et. al., Nucl. Instr. Meth. A 446 (2000)569 |
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| WEPCH067 | Implementation of TPSA in the Mathematica Code LieMath | lattice, sextupole, COSY, linear-collider | 2077 | ||
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The Lie Algebra package LieMath written in the Mathematica language constructs the beamline map in a single-exponent Lie generator form. The algorithm (BCH-based map concatenation) has been recently enhanced with Truncated Power Series Algebra (TPSA) techniques.The polynomials produced by the series expansion of the Hamiltonian are replaced with arrays of coefficients (derivative structures) and the Poisson bracket and BCH are defined as operations on such structures. We have confirmed the statement that using automatic differentiation instead of symbolic operations increases the speed by least an order of magnitude. The code is equipped with a MAD parser and a normal form block allowing it to extract nonlinear chromaticity and amplitude detuning. The notebook was applied in FFAG studies and may be useful for the linear collider final focus or collimation systems.
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| WEPCH072 | The High Order Non-linear Beam Dynamics in High Energy Storage Ring of FAIR | multipole, resonance, sextupole, lattice | 2083 | ||
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The High Energy Storage Ring (HESR) is part of the international project FAIR for antiproton physics with beam in the momentum range from 1.5 to 15 GeV/c to explore the research areas of hadron structure and quark-gluon dynamics. An important feature of the project is the combination of phase space cooled beams with thick internal targets. Therefore there are two obvious reasons of beam heating: the target-beam interaction and the intra-beam scattering. Another source of the beam size growth is the higher order resonances. In the paper we investigate the non-linear beam dynamics together with different correction schemes minimizing this effect and compare with other sources of beam heating. Since the tune working point has a spread dependent on the chromaticity correction scheme and space charge, we include in our consideration both effects as well. All beam dynamics calculations are carried out with the SIMBAD code from the Unified Accelerator Library (UAL). We use 10000 macro particles, grid sizes 64x64 and 1000 turns per run.
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| WEPCH165 | A Nonlinear Transport Line for the Optimization of F18 Production by the TOP Linac Injector | target, linac, proton, quadrupole | 2316 | ||
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The injector of the TOP Linac (Oncological Therapy with Protons), under development by ENEA and ISS, consists of a 7 MeV, 425 MHz RFQ+DTL (AccSys Model PL-7). It is actually in operation at ENEA-Frascati Laboratories for the production of the positron-emitting radionuclide F18 for PET analyses by an intense proton beam (8 - 10 mA, 50 - 100 μs, 30 - 100 Hz). At the exit of the injector, the beam is guided through a magnetic channel to a target composed by a thin chamber (0.5 mm thick and 1-inch diameter) containing water enriched with O18. Recently, to the original quadrupole transport channel, a non-linear magnet system using octupoles has been added in order to flatten the proton beam distribution and optimize the radioisotope production. In the paper the details of the octupole design and beam dynamic study and the first measurements results are presented.
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| WEPLS066 | Harmonic Measurement and Adjustment of Diamond Quadrupoles | sextupole, DIAMOND, quadrupole, alignment | 2532 | ||
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The 254 quadrupole magnets for Diamond, manufactured by Tesla Engineering Ltd, were measured for harmonic content to a level around 1 part in 104. In order to meet the demanding requirements on field quality, procedures were then developed to adjust the relative positions of the magnet quadrants such that the desired harmonic levels were achieved. This process was integrated into the analysis software so that the needed changes were specified. The measurements were performed on a seven-coil rotating coil rig, which also enabled the alignment of the magnet in five spatial degrees of freedom to the specified accuracy. In this report we describe the measurement and correction procedures and present a summary of the results that were obtained.
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| WEPLS098 | Experience with the Quality Assurance of the Superconducting Electrical Circuits of the LHC Machine | LHC, dipole, pick-up, quadrupole | 2604 | ||
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The coherence between the powering reference database and the Electrical Quality Assurance (ELQA) is guaranteed on the procedural level. However, a challenge remains the coherence between the database, the magnet test and assembly procedures, and the connection of all superconducting circuits of the LHC. In this paper, the methods, tooling, and procedures for the ELQA during the assembly phase of the LHC will be presented in view of the practical experience gained in the LHC tunnel. The parameters measured at ambient temperature such as the dielectric insulation and the impedance transfer function of assembled circuits will be discussed. Some examples of detected polarity errors and the treatment of non-conformities will be presented.
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| THPCH052 | Dependence of Transverse Instabilities on Amplitude Dependent Tune Shifts | betatron, feedback, ion, factory | 2904 | ||
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In the Photon Factory electron storage ring, transverse instabilities have been observed in multi-bunch operation mode. The instabilities can be suppressed by amplitude dependent tune shifts, which are induced by the sextupole, octupole and higher order magnetic field. Since four octupole magnets have been installed in the PF ring, we can control the tune shifts, which is caused by the octupole magnetic field, independently of chromaticities, which is caused by sextupole magnetic field. In order to research the suppression mechanism of the instabilities, we measured the dependence of the instabilities on the tune shifts, which are induced by the octupole field. The threshold of the tune shifts, which suppress the instabilities, were observed in the measurement, and it depended on the filling pattern of the bunch train and the beam current per bunch. In addition, we will present the results of the measurement before and after the reconstruction for the straight-sections upgrade at the PF ring, which was carried out in 2005.
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| THPLS013 | The Magnets of the Metrology Light Source in Berlin-Adlershof | quadrupole, dipole, sextupole, storage-ring | 3296 | ||
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PTB, the German National Metrology Institute in close cooperation with BESSY II, is currently carrying out the project of constructing the low-energy "Metrology Light Source" (MLS) as a synchrotron radiation facility situated in the close vicinity of BESSY II. Construction of the MLS housing is in progress and nearly finished. The user operation is scheduled to begin in 2008. Dedicated to metrology and technology development in the UV and EUV spectral range, the MLS will bridge the gap that is existent since the shutdown of BESSY I. A 100 MeV microtron delivered by Danfysik A/S will provide the electrons for the MLS with a structure of asymmetric double bend achromat. The total circumference of the MLS is 48 m. The electron energy is ramped to the desired value between 200 MeV and 600 MeV. The MLS magnetic lattice, consisting of 8 bending magnets, 24 quadrupole magnets, 24 sextupole magnets and 4 octupole magnets, is laid out to facilitate this operation. The contract for the MLS magnets is awarded to the Budker Institute for Nuclear Physics. A description of the MLS magnets based on the results of the factory acceptance tests should be presented.
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