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| TUP81 |
Superstrong Adjustable Permanent Magnet for a Linear Collider Final Focus
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462 |
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- Y. Iwashita, T. Mihara
Kyoto ICR, Kyoto
- A. Evgeny, M. Kumada
NIRS, Chiba-shi
- C. M. Spencer
SLAC, Menlo Park, California
- E. Sugiyama
NEOMAX, Osaka
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Super-strong permanent magnets are being considered as one of the candidates for the final focus quadrupole magnets in a linear collider. A short prototype with temperature compensation included and variable strength capability has been designed and fabricated. Fabrication details and some magnetic measurement results will be presented.
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Transparencies
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| TUP82 |
Low Energy Beam Transport using Space Charge Lenses
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465 |
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- O. Meusel, A. Bechtold, H. Klein, J. Pozimski, U. Ratzinger, A. Schempp
IAP, Frankfurt-am-Main
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Gabor lenses provide strong cylinder symmetric electric focusing using a confined nonneutral plasma. The density distribution of the enclosed space charge is defined by the enclosure conditions in transverse and longitudinal direction. For a homogeneous charge density distribution the resulting electrostatic field and therefrom the focusing forces inside the space charge cloud are linear. Additionally in case of a positive ion beam the space charge of the confined electrons causes compensation of the ion beam space charge forces. To study the capabilities of a Gabor double lens system to match an ion beam into a RFQ a testinjector was installed at the IAP and put into operation successfully. First beam profiles and emittance measurements as well as measurements of the beam energy and energy spread have already been performed and show satisfactory results and no significant deviation from the theoretical predictions. To verify the beam focusing of bunched beams using this lens type at beam energies up to 500 keV a new high field Gabor lens was build and will be installed behind of the RFQ.
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| TUP83 |
Results of the Magnetic Field Measurements of the DTL Quadrupole Magnets for the J-PARC
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468 |
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- E. Takasaki, F. Naito, H. Tanaka, K. Yoshino
KEK, Ibaraki
- H. Ino, Z. Kabeya, S. Kakizaki, T. Kawasumi
Mitsubishi Heavy Industries Ltd., Nagoya Aerospace Systems Works, Nagoya
- T. Itou
JAERI/LINAC, Ibaraki-ken
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A quadrupole electromagnet is installed in the drift tube, which has an outer diameter of 140 mm and its minimum length of 53 mm. Hence, a coil of this magnet was made by the advanced periodic reverse copper electroforming method instead of the conventional hollow conductor. Recently, 149 quadrupole electromagnets were completed and then installed in the drift tube within a high accuracy. The magnetic field measurements have been carried out with two different measurement methods at each stage of the manufacturing process. The discrepancies between the magnetic field center and the mechanical center are within about ±35 μm after installation of the quadrupole magnet inside the drift tube. This paper will describe methods and results of the magnetic field measurements.
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| TUP84 |
Spectrographic Approach to Study of RF Conditioning Process in Accelerating RF Structures
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471 |
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- H. Tomizawa, H. Hanaki, T. Taniuchi
JASRI-SPring-8, Hyogo
- A. Enomoto, Y. Igarashi, S. Yamaguchi
KEK, Ibaraki
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The acceleration gradient of a linac is limited by rf breakdown in its accelerating structure. We applied an imaging spectrograph system to study the mechanism of rf breakdown phenomena in accelerating rf structures. Excited outgases emit light during rf breakdown, and the type of outgases depend on surface treatments and rinsing methods for their materials. To study rf breakdown, we used 2-m-long accelerating structures and investigated the effects when high-pressure ultrapure water rinsing (HPR) treatment was applied to these rf structures. We performed experiments to study the outgases under rf conditioning with quadruple mass spectroscopy and imaging spectrography. As a result, we could observe instantly increasing signals at mass numbers of 2 (H2), 28 (CO), and 44 (CO2), but not 18 (H2O) just after the rf breakdown. We also conducted spectral imaging for the light emissions from the atoms in a vacuum that are excited by rf breakdown. Without HPR, we observed the atomic lines at 511 nm (Cu I), 622 nm (Cu II), and 711 nm (C I). With HPR, 395 nm (O I), 459 nm (O II), 511 nm (Cu I), 538 nm (C I), 570 nm (Cu I), 578 nm (Cu I), 656 nm (H I), and 740 nm (Cu II) were observed.
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