| Paper |
Title |
Page |
| TUP89 |
Static Absolute Force Measurement for Preloaded Piezoelements Used for Active Lorentz Force Detuning System
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486 |
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- S. P. Sekalski, A. Napieralski, S. P. Sekalski
TUL, Lodz
- A. Bosotti
INFN/LASA, Segrate (MI)
- M. Fouaidy
IPN, Orsay
- L. Lilje, S. Simrock
DESY, Hamburg
- R. Paparella, P.F. Puricelli
INFN Milano, Milano
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To reach high gradients in pulsed operation of superconducting (SC) cavities an active Lorentz force detuning compensation system is needed. For this system a piezoelement can be used as an actuator (other option is a magnetostrictive device). To guarantee the demanded lifetime of the active element, the proper preload force adjustment is necessary. To determine this parameter an absolute force sensor is needed which will be able to operate at cryogenic temperatures. Currently, there is no calibrated commercial available sensor, which will be able to measure the static force in such an environment. The authors propose to use a discovered phenomenon to estimate the preload force applied to the piezoelement. The principle of the proposed solution based on a shape of impedance curve, which changes with the value of applied force. Especially, the position of resonances are monitored. No need of specialized force sensor and measurement in-situ are additional advantages of proposed method.
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| TUP96 |
Mechanical Stability Simulations on a Quarter Wave Resonator for the SPIRAL II Project
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504 |
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- H. Saugnac, J.-L. Biarrotte, S. Blivet, S. Bousson, M. Fouaidy, T. Junquera, G. Olry
IPN, Orsay
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In the framework of the SPIRAL II project, IPN Orsay is studying a 88 MHz β=0.12 super conducting quarter wave resonator prototype. Due to its low RF bandwidth (around 60 Hz) the resonator must have a very high mechanical stability and have small sensitivity to dynamic mechanical loads. To simulate the effects of geometrical deformations on the fundamental RF frequency a three dimensional analysis is required. The simulations were made by coupling mechanical FEM analysis performed in COSMOS/GEOSTAR™ with the RF electromagnetic FEM code MICAV™ integrated in the COSMOS/GEOSTAR™ interface. Static mechanical loads were first studied to reduce the effects of external pressure on the RF frequency shift and evaluate the tuning sensitivity of the cavity. Then, simulations on the dynamic response of the resonator, using the modal superposition analysis method, with random external pressure variations and harmonic excitation of the cavity were performed. This paper presents the results of the simulations and mechanical solutions chosen to increase the cavity RF frequency stability.
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