| Paper |
Title |
Page |
| MOP36 |
Preliminary Study on HOM-Based Beam Alignment in the TESLA Test Facility
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117 |
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- N. Baboi, G. Kreps, M. Wendt
DESY, Hamburg
- G. Devanz, R. Paparella
CEA/DAPNIA-SACM, Gif-sur-Yvette Cedex
- O. Napoly
CEA/DSM/DAPNIA, Gif-sur-Yvette
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The interaction of the beam with the higher order modes (HOM) in the TESLA cavities has been studied in the past at the TESLA Test Facility (TTF) in order to determine whether the modes with the highest loss factor are sufficiently damped. The same modes can be used actively for beam alignment. At TTF the beam alignment based on the HOM signals is planned to be studied in the first cryo-module, containing 8 accelerating cavities. One of several modes with higher loss factor will be used. Its polarization has to be determined. The options to use single bunches or bunch trains will be analyzed. The results will be discussed in this paper.
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| 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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