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Title |
Other Keywords |
Page |
| MOPLT015 |
Reliability Issues of the LHC Beam Dumping System
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dumping, extraction, kicker, collider |
563 |
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- R. Filippini, E. Carlier, B. Goddard, J.A. Uythoven
CERN, Geneva
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The Beam Dumping System of the Large Hadron Collider, presently under construction at CERN, must function with utmost reliability to protect the personnel, minimize the risk of severe damage to the machine and avoid undue impact to the environment. The dumping action must be synchronized with the particle free gap and the field of the extraction and dilution elements must be well adjusted to the beam energy. The measures taken to arrive at a reliable and safe system will be described, like the adoption of fault tolerant design principles and other safety related features as comprehensive monitoring, diagnostics and protection facilities. These issues will be discussed in the general framework of the IEC standard recommendations for safety critical systems. Some examples related to the most critical functions will be included.
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| MOPLT096 |
Machine Induced Background in the High Luminosity Experimental Insertion of the LHC Project
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background, insertion, simulation, shielding |
755 |
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- V. Talanov, I. Azhgirey, I. Baishev
IHEP Protvino, Protvino, Moscow Region
- K.M. Potter
CERN, Geneva
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The methodical approach, developed for the solution of the radiation problems in the LHC project, is used for the estimation of the machine induced background in the high luminosity experimental insertion IR1. The results of the cascade simulations are presented for the cases of the proton losses in the cold and warm parts of the collider. The formation of the machine induced background in the interaction region is discussed.
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| MOPLT114 |
Modeling of Beam Loss in Tevatron and Backgrounds in the BTeV Detector
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beam-losses, collimation, shielding, background |
803 |
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- A. Drozhdin, N. Mokhov
Fermilab, Batavia, Illinois
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Detailed STRUCT simulations are performed of beam loss rates in the vicinity of the BTeV detector in the Tevatron C0 interaction region due to beam-gas nuclear elastic interactions, outscattering from the collimator jaws and an accidental abort kicker prefire. Corresponding showers induced in the machine components and background rates on the BTeV Detector are modeled with the MARS14 code. It is shown that a steel mask located in front of the last four dipoles upstream the C0 can reduce the accelerator-related background rates in the detector by an order of magnitude.
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| WEOBCH01 |
Performance Requirements for Monitoring Pulsed, Mixed Radiation Fields around High-energy Acclerators
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radiation, monitoring, target, simulation |
147 |
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- D. Forkel-Wirth, S.M. Mayer, H.G. Menzel, A. Muller, T. Otto, M. Pangallo, D. Perrin, M. Rettig, S. Roesler, L. Scibile, H. Vincke
CERN, Geneva
- C. Theis
TUG/ITP, Graz
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Radiation protection survey around CERN's High Energy Accelerators represents a major technical and physical challenge due to the pulsed and complexity of the mixed radiation fields. The fields are composed of hadrons, leptons and photons ranging in energy from fractions of eV to several 10 GeV. In preparation of the implementation of a Radiation Monitoring System for the Environment and Safety (RAMSES) of the future Large Hadron Collider (LHC) and its injectors comprehensive studies were performed to evaluate the suitability of different existing monitors for this task. Different ionization chambers were exposed to short, high-intensity radiation pulses and their saturation levels for high dose rates determined. Limiting factors such as recombination effects and the capacity of the electronics to process a high number of charges within very short time were studied in detail. These results are being used to optimize the design of the read-out electronics. In additional studies, the response of two different types of ionization chambers to high-energy radiation was investigated by measurements in the mixed radiation fields of the CERN EU high-energy Reference Field (CERF) facility. The results of the experiments agreed well with calculations, clearly demonstrating that modern Monte-Carlo simulation techniques can be used to design radiation monitors and to optimize their performance.
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Video of talk
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Transparencies
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| WEPKF037 |
Structural Analysis of an Integrated Model of Short Straight Section, Service Module, Jumper Connection and Magnet Interconnects for the Large Hadron Collider
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alignment, vacuum, collider, ground-motion |
1684 |
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- S. Dutta, J. Dwivedi, A. Kumar, H.C. Soni
CAT, Indore (M.P.)
- B. Skoczen
CERN, Geneva
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The Short Straight Section (SSS) of the Large Hadron Collider (LHC) houses a twin quadrupole.The cryogens are fed to the SSS through a Jumper Connection between service modules of Cryogenic Distribution Line (QRL) and SSS.A Finite Element analysis has been performed in collaboration with CERN for the unified model of SSS of LHC,consisting of cold mass, cold supports,vacuum vessel and its bellows, interconnects, jumper connection and alignment jacks. The model has been developed to understand coupling between the quadrupole magnet and the service module due to ground motion and during the realignment or global smoothening of the LHC arc. The model incorporates experimental stiffness values for support posts, internal pipes and jacks and calculated stiffness for magnet-to-magnet interconnects. The computation space and time has been reduced by executing a two step linear static analycal approach with an initial trial analytical approach cycle in which the program estimates the behavior of the flexibles. A special routine is developed within ANSYS,using APDL which selects the correct secant stiffness of flexibles(by applying a user interactive logical algorithm)from their non-linear force displacement characteristics.
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| WEPKF082 |
Radiation Damage Studies with Hadrons on Materials and Electronics
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radiation, permanent-magnet, multipole, radioactivity |
1795 |
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- J.E. Spencer, J. Allan, S. Anderson, R. Wolf
SLAC, Menlo Park, California
- M. Boussoufi
UCD/MNRC, McClellan, California
- D.E. Pellet
UCD, Davis
- J.T. Volk
Fermilab, Batavia, Illinois
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Many materials and electronic devices need to be tested for the radiation environment expected at the proposed linear colliders (LC) where the accelerator and detectors will be subjected to large fluences of hadrons, electrons and gammas during the life of the facility. Examples are NdFeB permanent magnets which are being considered for the damping rings and final focus, electronic and electro-optical devices which will be utilized in the detector readout and accelerator control systems and CCDs required for the vertex detector. The effects of gammas on a broad range of materials was presented at NSREC2002 and our understanding of the current situation concerning rare earth permanent magnets at PAC2003 where a program was proposed using neutrons from the McClellan Nuclear Reactor Center (MNRC) that has a number of areas for irradiating samples with neutron fluxes up to 4.5·1013 n/cm2s. A specialized area allows irradiation with 1 MeV-equivalent neutrons with fluxes of 4.2·1010 n/cm2s while suppressing thermal neutrons and gammas by large factors. We give our latest results and their interpretation using this facility.
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| WEPLT015 |
Proposal for the Creation and Storage of Long Bunches in the LHC
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luminosity, emittance, acceleration, injection |
1852 |
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- H. Damerau, R. Garoby
CERN, Geneva
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Long bunches with a uniform longitudinal line density held by barrier buckets are considered for a future luminosity upgrade of the Large Hadron Collider (LHC). With such bunches, the luminosity is maximised for a fixed number of particles. Instead of conventional barrier buckets, periodic barriers are proposed. These are generated with multiple RF harmonics (e.g. multiples of 40 MHz). A possible scheme to create and hold long flat bunches in the LHC is described, and the resulting gain in luminosity is estimated.
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| WEPLT021 |
Towards an Ontology Based Search Mechanism for the EDMS at CERN
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dipole, collider |
1870 |
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- A. Jimeno Yepes, B. Rousseau
CERN, Geneva
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CERN is building its new accelerator, the LHC. All the data flow generated during its lifecycle is stored in the EDMS (Engineering Data Management System) developed at CERN. For such a system it is compulsory to have a performant search mechanism to guarantee that the involved people gets the data at the required time. Due to the size of the collection and the diversity of people, organizations, divisions . To overcome this problem, an approach based on a hand-crafted domain specific ontology has been tested in order to improve the information retrieval task within the technical documentation for the LHC Equipment Catalog. The experiments have shown that using the ontology an improvement on the base line has been produced and encorages IE techniques to refine the base ontology.
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| WEPLT022 |
Transport and Installation of Cryo-magnets in CERN's Large Hadron Collider Tunnel
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acceleration, factory, dipole, collider |
1873 |
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- K. Kershaw, K. Artoos, O. Capatina, A.Y. Coin, M. Gielen, C. Hauviller
CERN, Geneva
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The arcs of the Large Hadron Collider (LHC) will contain around 1700 main superconducting dipoles and quadrupoles. The long and heavy magnets are supported on fragile composite support posts inside a cryostat to reduce the heat in-leak to the magnets' super fluid helium bath. The presence of fragile components and the need to avoid geometry changes make the cryo-magnets very difficult to handle and transport. The transport and installation of the LHC cryo-magnets in the LEP tunnels originally designed for smaller, lighter LEP magnets has required development of completely new handling solutions. The paper explains the constraints imposed by the cryo-magnet characteristics, the existing tunnel infrastructure and schedule considerations. The development and realisation of transport and handling solutions are described, starting from conceptual design, through manufacture and testing to the installation of the first cryo-magnet. Integration studies to verify and reserve space needed for manoeuvre and the preparation of the infrastructure for transport and installation operations are also presented. The paper includes conclusions and some of the lessons learned.
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| WEPLT094 |
Electromagnetic Fields of an Off-axis Bunched Beam in a Circular Pipe with Finite Conductivity and Thickness - II
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multipole, quadrupole, collider, electromagnetic-fields |
2071 |
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- S. Petracca, L. Cappetta, T. Demma
U. Sannio, Benevento
- R.P. Croce
Universita' degli Studi di Salerno, Dipartimento di Fisica E.R. Caianiello, Baronissi
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The general exact solution exploited [*] is applied, introducing suitable dimensionless parameters, and using appropriate asymptotic limiting forms, to compute the wake field multipoles for the different paradigm cases of LHC and DAPHNE.
* R. P. Croce, Th. Demma, S. Petracca "Electromagnetic Fields of an Off-axis Bunch in a Circular Pipe with Finite Conductivity and Thickness", these proceedings
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| THOBCH03 |
Barrier RF Systems in Synchrotrons
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antiproton, synchrotron, emittance, proton |
236 |
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- C.M. Bhat
Fermilab, Batavia, Illinois
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Recently, the barrier bucket techniques have been used in many interesting applications in proton synchrotrons around the world. Specially designed broad-band rf cavities are used to generate barrier buckets. At Fermilab we have barrier RF systems in four different rings and have used them for various beam gymnastics. Particularly, in the case of Fermilab Recycler Ring, all rf manipulations required during beam cooling, beam stacking and unstacking are carried out using barrier buckets. Also, we have explored new methods for increasing the beam intensities in the Main Injector. Here, I review various uses of barrier rf system in particle accelerators and possible new applications.
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Video of talk
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Transparencies
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| THPLT007 |
New Beam Profile Monitor Based on GEM Detector for the AD Transfer and Experimental Lines
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antiproton, cathode, electron, extraction |
2472 |
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- J. Bosser, K. Gnanvo, J. Spanggaard, G. Tranquille
CERN, Geneva
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Many multi-wire proportional chambers, (MWPC's), are installed on the CERN Antiproton Decelerator (AD) transfer and experimental lines. They are used for the steering and profile measurement of the low energy antiproton beam that is extracted at the energy of 5.3 MeV from the AD machine. At this very low energy, the standard MWPC's are not only destructive for the beam but also perturb strongly the 2D profile measurement. These chambers are also based on technology that is outdated and in recent years have shown to be fragile and expensive to repair. For these reasons a new, low cost profile monitor, based on a Gas Electron Multiplier (GEM) detector is under development as a possible replacement of the MWPC's. This new profile monitor will enable high precision, true 2D profile measurements of the low energy antiproton beam. In this paper, we present the modification of the standard GEM detector required by our specific application and the first results of the profile monitor with antiproton beams.
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| THPLT129 |
Ion Chambers for Monitoring the NuMI Beam at FNAL
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target, ion, proton, instrumentation |
2768 |
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- S.E. Kopp, D. Indurthy, R. Keisler, S. Mendoza, Z. Pavlovich, M. Proga, R.M. Zwaska
The University of Texas at Austin, Austin, Texas
- M. Diwan, B. Viren
BNL, Upton, Long Island, New York
- A.R. Erwin, H.P. Ping, C.V. Velisaris
UW-Madison/PD, Madison
- D. Harris, A. Marchionni, J. Morfin
Fermilab, Batavia, Illinois
- J. McDonald, D. Naples, D. Northacker
University of Pittsburgh, Pittsburgh, Pennsylvania
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We summarize selected instrumentation under construction for the NuMI neutrino beam facility at Fermilab. An array of foil secondary emission monitors (SEM's) will measure the 120GeV proton beam position, profile and halo at 10 stations along the transport to the NuMI target. The final two foil SEM's align the proton beam to within 50 microns on target. These are capable of withstanding the 400kW proton beam and causing <5·10-6 beam loss. Further instrumentation includes four stations of ionization chambers located downstream of the decay volume, one upstream and three downstream of the beam dump. The latter three monitor the tertiary muon beam, the first monitors the remnant hadron beam. The ion chamber arrays align the proton beam to 14microRadian and the neutrino beam to within 50 microRadian, as well as monitoring flux to better than 1%. The ion chambers are designed to withstand the ~1GRad doses and 109 particle/cm2/spill fluxes anticipated during NuMI beam operations. Beam tests and R&D efforts are discussed.
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