| Paper |
Title |
Page |
| MOPCH103 |
SPIRAL2 RFQ Prototype – First Results
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282 |
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- R. Ferdinand, R. Beunard, V. Desmezières, M. Di Giacomo, P. Robillard
GANIL, Caen
- A.C. Caruso
INFN/LNS, Catania
- S. Cazaux, M. Desmons, A. France, D. Leboeuf, O. Piquet, J.-C. Toussaint
CEA, Gif-sur-Yvette
- M. Fruneau, Y. Gómez-Martínez
LPSC, Grenoble
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The SPIRAL2 RFQ has been designed to accelerate a 5 mA deuteron beam (Q/A=1/2) or a 1 mA particle beam with q/A=1/3 up to 0.75 MeV/A at 88MHz. It is a CW machine which has to show stable operation, provide the required availability and reduce losses to a minimum in order to minimize the activation constraints. Extensive modelisation was done to ensure a good vane position under RF. The prototype of this 4-vane RFQ has been built and tested in INFN-LNS Catania and then in IN2P3-LPSC Grenoble. It allowed us to measure the vacuum quality, the RF field by X-ray measurements, the cavity displacement and the real vane displacement during the RF injection. Different techniques were used, including an innovative and effective CCD measurement with a 0.6 μm precision. This paper outlines the different results.
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| MOPCH105 |
A New RF Tuning Method for the End Regions of the IPHI 4-vane RFQ
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285 |
| |
- O. Delferriere, M. Desmons, A. France
CEA, Gif-sur-Yvette
- R. Ferdinand
GANIL, Caen
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The 3-MeV High Intensity Proton Injector (IPHI) RFQ is constituted by the assembly of three 2-m-long segments. The tuning of the end regions of such an accelerator with respect to the quadrupole mode is generally made by machining the thickness of the end plates. The dipole modes are moved away from the accelerator mode frequency by adding dipole rods and adjusting their length. In the case of the last IPHI RFQ segment, the tuning range given by possible plate thickness was not sufficient to adjust the frequency at 352 Mhz without modifying the notch depth, leading to serious engineering problems for the cooling, new thermo-mechanical simulations and drawings. To avoid these difficulties, a new way has been investigated by replacing the end plate thickness adjustment by a "quadrupole rod" length adjustment. These rods are situated between the beam axis and the dipole rods, and the tuning range is largely increased. The paper will describe this method applied to the IPHI RFQ and some experimental results obtained on the cold model.
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| MOPCH107 |
Tuning Procedure of the 6 Meter IPHI RFQ
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291 |
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- O. Piquet, M. Desmons, A. France
CEA, Gif-sur-Yvette
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In the framework of the IPHI project (High Intensity Proton Injector), the RFQ cavity is divided into 6 sections of 1 meter each, and assembled in 3 segments separated by coupling plates. We will present the tuning procedure of the aluminium RFQ cold model to set the accelerating mode frequency, a flat voltage profile and to minimize the dipole components of the accelerating voltage. This tuning procedure can be divided in three steps. First, dipole mode frequencies are adjusted with rods for the 3 separated segments. Second, RFQ end cells and coupling cells are tuned by mechanical machining of tuning plates. Third, using a fully automated bead-pull for the measurement of the field distribution inside every RFQ quadrants, the RFQ is tuned with 96 plungers in a small number of iterations. Tuning this 6-meter long cold model is a comprehensive training in view of the future tuning of the copper RFQ with the variable voltage profile.
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| MOPCH140 |
Compensation of Lorentz Force Detuning of a TTF 9-cell Cavity with a New Integrated Piezo Tuner
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378 |
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- G. Devanz, P. Bosland, M. Desmons, E. Jacques, M. Luong, B. Visentin
CEA, Gif-sur-Yvette
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The high gradient operation of superconducting elliptical multicells in pulsed mode is required for linear colliders or free-electron lasers based on the superconducting technology. Such an operation is limited by dynamic Lorentz force detuning if no compensation for this effect is attempted. The RF power headroom required for accelerating field amplitude and phase stabilisation by low-level RF control techniques solely would be too costly. A new active tuner with integrated piezo actuators has been developped in the framework of the european CARE/SRF program solve this issue. The design is based on the lever-arm concept of the Saclay tuner already installed on running TTF cavities. We have carried out integrated tests of the 9-cell cavity equipped with the piezo tuner and power coupler in the CryHoLab horizontal test cryostat. Characterisation of the electromechanical system consisting of the cavity and piezo-tuner assembly and full power pulsed tests will be presented.
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| MOPLS114 |
Construction of the Probe Beam Photo-injector of CTF3
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828 |
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- J. Brossard, M. Desmons, B.M. Mercier, C.P. Prevost, R. Roux
LAL, Orsay
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The paper describes the HF and dynamic beam modelling performed onto the 3 GHz / 2,5 cells photo-injector of the future CTF3 (CLIC Test Facility 3) probe beam linac, whose goal is to demonstrate the feasibility of the 30 GHz accelerating sections in the framework of the CLIC project. The Probe Beam Photo-Injector (PBPI) conception is inspired from the drive beam photo-injector already designed by LAL (Orsay, France) and actually tested in our laboratory. However, the design of PBPI has been simplified with respect to the previous because the charge per bunch is 4 times lower and the number of bunches several orders of magnitude smaller. The internal geometry and the coupling system of the PBPI have been designed with 2D (SUPERFISH) and 3D (HFSS, ANSYS) codes. A detailed analysis of the dissymmetry (induced by the coupling system) of the accelerating field component has been performed. Based on the modified design, PARMELA simulations showed that the technical specifications are fulfilled. The vacuum issue has been also carefully investigated, and NEG (Non Evaporated Getter) technology has been adopted in order to reach the 10-10 mbar pressure inside the structure.
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| MOPLS113 |
Commissioning of the ALTO 50 MeV Electron Linac
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825 |
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- J. Lesrel, J. Arianer, M. Arianer, O. Bajeat, J-M. Buhour, H. Bzyl, F. Carrey, M. Chabot, J.-L. Coacolo, T. Corbin, H. Croizet, J.-M. Curaudeau, F. Doizon, M. Ducourtieux, J.-M. Dufour, S. Essabaa, D. Grialou, C. Joly, M. Kaminski, H. Lefort, B. Lesellier, G. Magneney, L. Mottet, Y. Ollivier, C. Planat, M. Raynaud, Y. Richard, A. Said, A. Semsoum, F. Taquin, C. Vogel
IPN, Orsay
- G. Bienvenu, J-N. Cayla, M. Desmons
LAL, Orsay
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The ALTO 50 MeV electron linac is dedicated to the production of neutron-rich radioactive nuclei using the photo-fission process and the optimisation of the target-ion source system for SPIRAL 2 and Eurisol projects. A description of the accelerator consisting in 3 Mev injector (old test station of LAL), LIL accelerating structure, RF power plant, beam line, control system and diagnostics will be given. Specified and measured beam parameters will be compared to show the performance for the photo-fission and eventually other applications.
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