| Paper |
Title |
Page |
| 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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| MOPCH142 |
Commissioning of the SOLEIL RF Systems
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384 |
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- P. Marchand, H.D. Dias, M.D. Diop, M.E. El Ajjouri, J.L. Labelle, R.L. Lopes, M. Louvet, C.M. Monnot, J. Polian, F. Ribeiro, T. Ruan, R.S. Sreedharan, K. Tavakoli, C. Thomas-Madec
SOLEIL, Gif-sur-Yvette
- P. Bosland, P. Bredy
CEA, Gif-sur-Yvette
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The 352 MHz RF accelerating systems for the SOLEIL Booster (BO) and Storage Ring (SR) are being commissioned. In the BO a 5-cell copper cavity of the CERN-LEP type is powered with a 35kW solid state amplifier. In the SR the required RF accelerating voltage (up to 4.4MV) will be provided by two cryomodules, each containing a pair of superconducting cavities, specifically designed for SOLEIL. The parasitic impedances of the high order modes are strongly attenuated by means of four coaxial couplers, located on the tube connecting the two cavities. The first cryomodule is already installed in the SR tunnel, while the second one is being constructed by ACCEL (Germany). These cryomodules are supplied in liquid helium from a single 350W liquefier and each cavity is powered with a 190kW solid state amplifier. The RF system commissioning and first operation results are reported.
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| MOPCH145 |
Tests Results of the Beta 0.07 and Beta 0.12 Quarter Wave Resonators for the SPIRAL2 Superconducting Linac
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393 |
| |
- G. Olry, J.-L. Biarrotte, S. Bousson, C. Joly, T. Junquera, J. Lesrel, G. Martinet, D. Moura, H. Saugnac, P. Szott
IPN, Orsay
- P.-E. Bernaudin, P. Bosland, G. Devanz
CEA, Gif-sur-Yvette
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New developments and tests have been carried out on low beta (0.07) and high beta (0.12) 88 MHz superconducting Quarter Wave Resonators. These resonators will be installed in the LINAC driver, respectively in the low beta section, composed of cryomodules A (developed at CEA-Saclay) and the high beta section composed of cryomodules B (developed at IPN-Orsay). Both resonators' types will be equipped with the same power coupler (developed at LPSC-Grenoble) and designed for a maximum power of 20 kW. RF tests results of the prototype cavities and power couplers are reported. The fabrication of the two cryomodules prototypes, fully equipped, is in progress in order to be ready for high power RF tests at 4.2 K at the beginning of 2007.
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| THPCH159 |
Analysis of Microphonic Disturbances and Simulation for Feedback Compensation
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3167 |
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- M. Luong, P. Bosland, G. Devanz, E. Jacques
CEA, Gif-sur-Yvette
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For FEL projects based on a superconducting linac operating in CW mode, the RF power optimization finally comes up against the microphonics disturbances, which result in an unpredictable detuning of the cavities. A new piezoelectric tuner was developed and mounted on a TTF 9-cell cavity with an appropriate instrumentation. This system enables a full characterization of the disturbances and the tuner behavior. First measurements were made in a horizontal cryomodule at 4.2 K. They set a basis for simulations to assess the possibility of a feedback compensation, which is usually credited as impracticable. The outcome of such a compensation is also shown in terms of acceleration voltage amplitude and phase residual errors.
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