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In this paper we discuss longitudinal beam coupling impedance measurements performed with the coaxial wire method on a modified prototype of the SPS MKE kicker. The frequency dependent real and imaginary part of the distributed coupling impedance are obtained from the measured S-parameters by standard and improved log-formulae. A comparison with theoretical(More)
In order to measure the electron cloud density, a microwave transmission measurement was set up over 30 m in the SPS beam pipe. The use of TE waveguide modes eliminates direct interaction with the highly relativistic beam. An electron cloud present in the beam pipe should lead to a small phase shift of the CW microwave signal. Since this phase shift is(More)
The LHC crab cavity program is advancing rapidly towards a first prototype which is anticipated to be tested during the early stages of the LHC phase I upgrade and commissioning. The general project status and some aspects related to crab optics, collimation, aperture constraints, impedances, noise effects, beam transparency and machine protection critical(More)
The TOTEM collaboration has developed and tested the first prototype of its Roman Pots to be operated in the LHC. TOTEM Roman Pots contain stacks of silicon detectors with strips oriented in two orthogonal directions. To measure proton scattering angles of a few microradians, the detectors will approach the beam centre to a distance of 10 σ + 0.5 mm (= 1.3(More)
Fast pulsed magnets with ferrite yokes are used in CERN's SPS accelerator for beam injection, extraction and excitation for tune measurements. The impedance of the ferrite structures can provoke significant beam induced heating, especially for beams with high peak currents as for LHC operation, even beyond the Curie temperature. The expected heating in the(More)
A rotatable collimator is proposed for the LHC phase II collimation upgrade. When the beam crosses the collimator, it will excite trapped modes that can contribute to the beam energy loss and power dissipation on the vacuum chamber wall. Transverse trapped modes can also generate transverse kicks on the beam and may thus affect the beam quality. In this(More)
The CERN Large Hadron Collider (LHC) is now in luminosity production mode and has been pushing its performance in the past months by increasing the proton beam brightness, the collision energy and the machine availability. As a consequence, collective effects have started to become more and more visible and have effectively slowed down the performance(More)
Motivated by the discussions on scenarios for LHC upgrades , beam studies on the stability of flat bunches in a double-harmonic RF system have been conducted in the CERN Proton Synchrotron (PS). Injecting nearly nominal LHC beam intensity per cycle, 18 bunches are accelerated on harmonic h = 21 to 26 GeV with the 10 MHz RF system. On the flat-top, all(More)
This report contains the Proceedings of the joint CARE-HHH-APD, CARE ELAN, and EUROTEV-WP3 Mini-Workshop on 'Electron Cloud Clearing Electron Cloud and Technological Consequences', " ECL2 " , held at CERN in Geneva, Switzerland, 1-2 March 2007). The ECL2 workshop explored novel technological remedies against electron-cloud formation in an accelerator beam(More)