Wenninger, J.

Paper	Title	Page
TUPC098	Results of the LHC Prototype Chromaticity Measurement System Studies in the CERN-SPS	1290
	R. J. Steinhagen, A. Boccardi, T. Bohl, M. Gasior, O. R. Jones, J. Wenninger CERN, Geneva K. K. Kasinski AGH, Cracow
	Tune and chromaticity control is an integral part of safe and reliable LHC operation. Tight tolerances on the maximum transverse beam excursions allow oscillation amplitudes of less than 30 um. This leaves only a small margin for transverse beam and momentum excitations required for measuring tune and chromaticity. This contribution discusses the baseline LHC continuous chromaticity measurement with results from tests at the CERN-SPS. The system is based on continuous tracking of the tune using a phase-locked-loop (PLL) while modulating the beam momentum. The high PLL tune resolution achieved ( ~1·10-6 ) made it possible to detect chromaticity changes well below the nominally required 1 unit for relative momentum modulations of only 2·10-5. The sensitive tune measurement front-end employed allowed the PLL excitation and radial amplitudes to be kept below a few tens of micrometers. These results show that this type of measurement can be considered as practically non-perturbative permitting its use even during nominal LHC operation.
WEZG01	Protection Controls for High Power Accelerators	1921
	J. Wenninger CERN, Geneva
	The next generation hadron accelerators will operate with MW beams or store beams with an energy of many 100 MJ. Machine protection will constrain operation, but some operational flexibility is still required for commissioning and performance optimization. This is a substantial challenge for control systems and application programs. New tools are developed to face those challenges: critical settings management, software interlocks, role based access to equipment, automatic accelerator mode recognition etc. This talk presents some of the challenges and tools. Experience with novel approaches are discussed.
	Slides
MOPC131	Ions for LHC: Towards Completion of the Injector Chain	376
	D. Manglunki, M. Albert, M.-E. Angoletta, G. Arduini, P. Baudrenghien, G. Bellodi, P. Belochitskii, E. Benedetto, T. Bohl, C. Carli, E. Carlier, M. Chanel, H. Damerau, S. S. Gilardoni, S. Hancock, D. Jacquet, J. M. Jowett, V. Kain, D. Kuchler, M. Martini, S. Maury, E. Métral, L. Normann, G. Papotti, S. Pasinelli, M. Schokker, R. Scrivens, G. Tranquille, J. L. Vallet, B. Vandorpe, U. Wehrle, J. Wenninger CERN, Geneva
	The CERN LHC experimental programme includes heavy ion physics with collisions between two counter-rotating Pb82+ ion beams at a momentum of 2.76 TeV/c/nucleon per beam and luminosities as high as 1·1027 cm-2 s-1. To achieve the beam parameters required for this operation the ion accelerator chain has undergone substantial modifications. Commissioning with beam of the various elements of this chain started in 2005 and in 2007 it was the turn of the final stage, the Super-Proton-Synchrotron (SPS) following extensive changes to the low-level RF hardware. The major limitations of this mode of operation of the SPS (space charge, intra-beam scattering) are presented, together with the performance reached so far. The status of the pre-injector performance will also be reviewed together with a description of the steps required to reach nominal performance.
WEPP065	Beam Commissioning of the SPS-to-LHC Transfer Line TI 2	2668
	J. A. Uythoven, G. Arduini, R. W. Assmann, N. Gilbert, B. Goddard, V. Kain, A. Koschik, T. Kramer, M. Lamont, V. Mertens, S. Redaelli, J. Wenninger CERN, Geneva
	The transfer line for the LHC Ring 1 was successfully commissioned with beam in the autumn of 2007. After extraction from the SPS accelerator and about 2.7 km of new transfer line, the beam arrived at the temporarily installed beam dump, about 50 m before the start of the LHC tunnel, without the need of any beam threading. This paper gives an overview of the hardware commissioning period and the actual beam tests carried out. It summarises the results of the beam test optics measurements and the performance of the installed hardware.
THPC082	Wire Excitation Experiments in the CERN SPS	3176
	U. Dorda, J.-P. Koutchouk, R. Tomas, J. Wenninger, F. Zimmermann CERN, Geneva R. Calaga, W. Fischer BNL, Upton, Long Island, New York
	In order to study the effect of long range interaction and its wire compensation experimentally, current carrying wires are installed in the CERN Super Proton Synchrotron (SPS). In this paper we summarize the main results of the 2007 wire excitation results at 26, 37 and 55 GeV including wire-current-, beam-wire distance and chromaticity scans. A strong dependence on the chromaticity and indications of a threshold effect at 37 and 55 GeV was found. The results are compared to simulation, to a simple analytic scaling law and to experimental results from RHIC. Wire-driven resonances have been observed through the Fourier spectrum of experimental BPM data and compared to simulations.
THPC145	Reliability Analysis of the LHC Machine Protection System: Terminology and Methodology	3327
	S. Wagner Swiss Federal Institute of Technology Zurich (ETH), Laboratory for Safety Analysis, Zurich R. Schmidt, J. Wenninger CERN, Geneva
	The trade-off between LHC machine safety and beam availability is one of the main issues related to the LHC MPS. Several studies have addressed it for different subsystems. They are followed by a project aiming at the development of a methodology which combines agent-based modeling and fault-tree analysis thus allowing a global analysis of the entire MPS. During this project, the need for a clarification and specification of the terminology has become apparent. Besides involving basic terms like safety, reliability and availability, the analysis must take into account the implementation of common design principles such as redundancy, fault tolerance, 'fail-safe' and self-monitoring. These terms and in particular their interrelations easily cause confusion. Since the traceability of the analysis depends on a consistent understanding of the underlying terminology, a terminology frame is being compiled. The paper specifies the most relevant terms and their interrelations. General standard definitions are taken as basis for a specification related to the MPS and its analysis respectively. The developed analysis methodology building on this terminology frame is introduced.