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Lyn Evans (CERN)03/09/2007, 14:00
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Rudiger SCHMIDT (CERN)03/09/2007, 14:10Objectives and questions
The idea to organise this workshop came up during the High Intensity High Brightness Hadron Beams workshop, HB2006, Tsukuba, Japan (2006). This workshop will focus on problems and solutions for absorbers and collimators for accelerators with Multi-MJoule stored beam energy. The objective of the workshop is to better understand the technological limits imposed by...
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Ralph ASSMANN (CERN)03/09/2007, 14:20LHC requirements for collimatorsLHC foresees a staged implementation of collimation. The first stage is presently being constructed and installed. A second stage should allow an even higher performance reach and shoul address several possible limitations in the initial installation. Collimators are the closest elements to the high-intenisty LHC beam and must be designed to directly intercept beam particles. The...Go to contribution page
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Brennan Goddard (CERN)03/09/2007, 14:50Beam absorbers for Machine Protection at LHC and SPS
A variety of machine protection absorbers are foreseen for the SPS and the LHC, to protect against failures during injection and extraction. The functional requirements for the different devices are presented, including expected operating conditions and anticipated performance limitations. General design constraints are briefly discussed, and some issues are outlined for possible...
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Nikolai MOKHOV (FERMILAB)03/09/2007, 15:45Tevatron Collider Collimators and AbsorbersBeam collimation is mandatory at any superconducting collider to protect components against excessive irradiation, minimize backgrounds in the experiments, maintain operational reliability over the life of the machine, and reduce the impact of radiation on environment, both at normal operation and accidental situations. Highly-efficient two-stage collimation system at Tevatron reliably...Go to contribution page
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Eric Doyle (SLAC)03/09/2007, 16:15Phase II collimators for LHC upgrade at SLACA rotatable collimator as developed at SLAC for NLC was proposed for LHC’s Phase II upgrade to provide a low impedance metal collimator, able to recover from several damaging hits by the beam. This talk reviews the technical problems involved, the FLUKA/ANSYS simulations which have guided our design decisions and the materials considered for the jaws. It focuses on the the reasons for...Go to contribution page
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Jens STADLMANN (GSI)03/09/2007, 16:45Lattice optimization for low charge state heavy ion operation - Collimation concepts for beam ions after a charge changeWe present a new lattice design concept for heavy ion synchrotrons which is optimized for the control of beam loss by projectile ionization. The lattice cells of the FAIR SIS100 synchrotron has been designed as charge separators. Thereby ionized projectiles are well separated from the reference beam. The generated peaked loss distribution enables the operation of a highly efficient...Go to contribution page
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Juan Luis Fernandez Hernando (STFC/ASTeC)03/09/2007, 17:15Design and testing of ILC Beam Delivery System collimators
At the ILC, the removal of halo particles having large amplitudes relative to the ideal orbit is mandatory to both minimise damage to beam line elements and particle detectors and to achieve tolerable background levels in the latter. In the high energy, high intensity environment of the linear collider the low background levels will largely be ensured by placing a set of mechanical...
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Alessandro BERTARELLI (CERN)04/09/2007, 08:30LHC Collimators (Phase II): What is an ideal material?The collimation system which is being installed has been designed to ensure high robustness during the LHC start-up and initial luminosity runs (Phase I). However, RF studies predict that the Phase I collimator impedance will prevent the machine from attaining its nominal luminosity. Hence, from the early phases of design, it has been envisaged to complement this system with a series of...Go to contribution page
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Ludger WEBER (EPFL)04/09/2007, 09:00Diamond-based Metal CompositesHigh end applications as the beam collimators for the LHC or first wall materials in fusion reactors require not only innovative engineering of the assembly and the structural parts but require also unique property combinations of the materials they are made of, e.g. good electrical conductivity, high thermal conductivity, low absorption of elemental particles, low coefficient of thermal...Go to contribution page
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René NAGEL (ARC)04/09/2007, 09:30Copper based composites reinforced with carbon nanofibersThe Powder Technology Center of the Austrian Research Centers GmbH is working since several years on the development of materials with advanced thermal properties. Different Cu and Al based fiber or particle reinforced composites have been studied. As reinforcement materials carbon fibers, carbon nanofibers (nanotubes), SiC or diamond particles have been used to prepare materials with...Go to contribution page
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Sven KNIPPSCHEER (PLANSEE SE)04/09/2007, 10:25Development and manufacturing status of diamond-based compositesAdvanced metal diamond composites with Silver, Aluminum and Copper matrices exhibit high thermal conductivity in the range of 400-700 W m-1 K-1 and low CTE of about 7 – 9 ppm/K. A gas pressure assisted infiltration process has been developed for cost-efficient industrial production of diamond composite substrates and heat sinks. The composite microstructure and interface morphology...Go to contribution page
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Carsten Omet (GSI)04/09/2007, 10:55Dynamic vacuum - Collimator technology for suppression and control of desorption gasesDuring operation with low charge state heavy ions (e.g. U28+) in the GSI synchrotron SIS18, fast beam losses have been observed in experiments. At the same time, a dynamic behaviour of the residual gas pressure was observed. To evercome these problems, a collimator system has been devoped and is now in the final preparation for installation into two of the twelve sectors of SIS18 in the...Go to contribution page
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Javier Narciso (Alicante University)04/09/2007, 11:25Carbon-metal composites for thermal managementCarbon-metal matrix composites are a very attractive materials for thermal applications, given their very high thermal conductivity in at least two planes. Therefore, in an attempt to obtain a good thermal conducting material as well as a low Coefficient of Thermal Expansion (CTE), a mixture of reinforcements (graphite and carbon fibre) was infiltrated with liquid alloys. The role of...Go to contribution page
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04/09/2007, 11:55
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Herta Richter (CERN)04/09/2007, 14:00Measurement of shock waves and vibrations
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Stefano REDAELLI (CERN)04/09/2007, 14:30Accelerometer and microphone measurementsSound and vibration measurements of the LHC collimator were performed with various accelerometers and a microphone during collimator robustness tests in 2004 and 2006. The collimator jaws were hit by 450 GeV protons beam of up to 3.5x10e13, equivalent to a total energy of about 2.4 MJ (0.65% of the nominal LHC beam at 7 TeV). It was demonstrated that these measurements can be used to...Go to contribution page
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Massimiliano AVALLE (POLITECNICO DI TORINO)04/09/2007, 15:00Experimental methods for material measurements at high strain-rateThe detailed mechanical characterization of a material is the very first step in the design of structural components. Depending on the type of application (dynamic, impact, thermal loading, fatigue...) different types of tests, experimental methods, and testing equipments are required. After a general introduction about the effects of dynamic loading on material behaviour, several...Go to contribution page
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Nick SIMOS (BNL)04/09/2007, 15:55Irradiation damage in LHC beam collimating materialsDemand for high-performance materials that can safely intercept the LHC proton beam has prompted an extensive experimental study focusing on material degradation due to long radiation exposure. Given the multi-MW class of the beam interception process at LHC combined with the stringent positional requirements on the intercepting elements, the envelope of the current knowledge regarding...Go to contribution page
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Alexander RYAZANOV (KURCHATOV INSTITUTE)04/09/2007, 16:25Studies of radiation effects on graphite collimator materialsThe effect of the 7 TeV proton beam irradiation on degradation of physical mechanical properties of graphite collimator materials for LHC is very important for the understanding of stability the collimators during operation of the LHC. At such high energies the carbon atoms in graphite collimator materials of LHC can get also very high energy with primary knock on carbon atoms (PKA)...Go to contribution page
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Ralph Wolfgang Assmann (CERN)04/09/2007, 16:55
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04/09/2007, 17:25
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Raymond Veness (CERN)05/09/2007, 08:30Issues Raised by the Design of the LHC Beam Dump Entrance WindowThe LHC beam dump entrance window consists of a carbon-carbon composite structural sheet backed by a thin stainless steel foil for leak tightness. The design of this window has highlighted issues that merit further investigation. The use of the bulk coefficient of thermal expansion coefficient for the composite should be questioned where there is a significant temperature gradient between...Go to contribution page
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Markus BRUGGER (CERN)05/09/2007, 09:00Overview of FLUKA Energy Deposition and Design Studies for the LHCIn order to assess the energy deposition in sensitive LHC components, extensive simulations were performed with the Monte Carlo cascade code FLUKA. In many cases specialized solutions needed to be found, challenging in several aspects, i.e., from the calculation as well as from the design point-of-view. Depending on the problem, detailed geometrical implementations, an accurate...Go to contribution page
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Markus BRUGGER (CERN)05/09/2007, 09:40Generic studies of radioactivity induced by high energy beams in different absorber materialsA rigorous campaign of benchmark measurements for materials typically used at accelerators has shown the high accuracy of FLUKA calculations for isotope production and residual dose rates. Accurate estimates of both quantities are important during all phases of an accelerator, i.e., design, operation and decommissioning. A detailed implementation of geometries and accurate consideration of...Go to contribution page
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George SMIRNOV (CERN)05/09/2007, 10:35Studies of radiation effects on graphite collimator materialsThe current status of the code development for simulating the structural damage of the graphite jaws of the LHC collimators produced by 7 TeV protons is presented. The technique, which is being developed in the framework of the Monte Carlo code FLUKA, combined with the results of experimental tests of carbon-carbon composite materials in radiation hard environment will be capable of...Go to contribution page
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Naeem TAHIR (GSI)05/09/2007, 11:00
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Alessandro DALLOCCHIO (CERN)05/09/2007, 11:40FE simulation of 450 GeV injection error testDynamic phenomena provoked by the rapid interaction of energetic particle beams with slender structures usually known as thermally induced vibrations are presented. Specific regard is given to the analysis of the accident case triggered by a beam injection error at 450 GeV, recently tested at CERN on LHC collimator prototypes. A simplified analytical method, which was previously...Go to contribution page
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Alexander RYAZANOV (KURCHATOV INSTITUTE)05/09/2007, 12:05Beam impact on collimator materials: Studies for LHC by Kurtchatov InstituteTheoretical models and numerical calculations are presented here to understand an influence of the impact of a 7 TeV proton beam on the physical-mechanical properties of collimator materials (C, Cu) used in the LHC. Here we develop the theoretical model for shock wave propagation and theoretical model for calculations of primary radiation damage formation including calculations of a...Go to contribution page
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Alessandro Bertarelli (CERN)05/09/2007, 14:00FE codes for thermo-mechanical analysis for Phase I collimationThe functional requirements of the LHC Collimators impose, for the start-up of the machine and the initial luminosity runs (Phase 1), a collimation system with a very high dimensional stability in nominal operating conditions, under considerable thermal loads and, at the same time, maximum robustness in case of accidental beam impacts. In order to meet these requirements and to optimize...Go to contribution page
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Nick SIMOS (BNL)05/09/2007, 14:30Experience with Implicit and Explicit codes in analyzing beam-induced thermo-mechanical shockIn an effort to extrapolate the interaction of intense proton pulses with materials to power levels beyond those achieved to-date in accelerators, computational schemes based on finite element formulation are being widely employed. While the long-term interaction between radiating particles and materials result in the degradation of the ability of a material to absorb the induced shock,...Go to contribution page
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Luca Bruno (CERN)05/09/2007, 15:00Numerical tools for the design of beam intercepting devicesBeam intercepting devices (collimators, targets, absorbers) capable of sustaining high-intensity beams are key elements to meet the future physics needs. The highly non-linear phenomena involved in their design study (cavitation, transient magnetic-hydrodynamic effects on liquid metal jets, phase change, fluid-structure interactions) require advanced simulation tools at the forefront of...Go to contribution page
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Rocio CHAMIZO (CERN)05/09/2007, 15:30
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Luca Massidda (CRS4)05/09/2007, 15:55Dynamic structural analysis of absorbers with spectral-element code ELSEThe dynamic structural behavior of beam diluter elements TCDS (LHC) and TPSG (SPS), protecting the extraction septum magnets in the event of an asynchronous firing of the extraction kickers, has been studied. The deposited energy densities, estimated by the high-energy particle transport code FLUKA, were converted to internal heat generation rates according to the time dependence of the...Go to contribution page
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Rüdiger Schmidt (CERN)05/09/2007, 16:35
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Markus Brugger (CERN)
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