Lyn Evans
(CERN)
03/09/2007, 14:00
Rudiger SCHMIDT
(CERN)
03/09/2007, 14:10
Objectives 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...
Ralph ASSMANN
(CERN)
03/09/2007, 14:20
LHC requirements for collimators
LHC 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...
Brennan Goddard
(CERN)
03/09/2007, 14:50
Beam 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...
Nikolai MOKHOV
(FERMILAB)
03/09/2007, 15:45
Tevatron Collider Collimators and Absorbers
Beam 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...
Eric Doyle
(SLAC)
03/09/2007, 16:15
Phase II collimators for LHC upgrade at SLAC
A 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...
Jens STADLMANN
(GSI)
03/09/2007, 16:45
Lattice optimization for low charge state heavy ion operation - Collimation concepts for beam ions after a charge change
We 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...
Juan Luis Fernandez Hernando
(STFC/ASTeC)
03/09/2007, 17:15
Design 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...
Alessandro BERTARELLI
(CERN)
04/09/2007, 08:30
LHC 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...
Ludger WEBER
(EPFL)
04/09/2007, 09:00
Diamond-based Metal Composites
High 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...
René NAGEL
(ARC)
04/09/2007, 09:30
Copper based composites reinforced with carbon nanofibers
The 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...
Sven KNIPPSCHEER
(PLANSEE SE)
04/09/2007, 10:25
Development and manufacturing status of diamond-based composites
Advanced 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...
Carsten Omet
(GSI)
04/09/2007, 10:55
Dynamic vacuum - Collimator technology for suppression and control of desorption gases
During 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...
Javier Narciso
(Alicante University)
04/09/2007, 11:25
Carbon-metal composites for thermal management
Carbon-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...
Herta Richter
(CERN)
04/09/2007, 14:00
Measurement of shock waves and vibrations
Stefano REDAELLI
(CERN)
04/09/2007, 14:30
Accelerometer and microphone measurements
Sound 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...
Massimiliano AVALLE
(POLITECNICO DI TORINO)
04/09/2007, 15:00
Experimental methods for material measurements at high strain-rate
The 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...
Nick SIMOS
(BNL)
04/09/2007, 15:55
Irradiation damage in LHC beam collimating materials
Demand 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...
Alexander RYAZANOV
(KURCHATOV INSTITUTE)
04/09/2007, 16:25
Studies of radiation effects on graphite collimator materials
The 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)...
Ralph Wolfgang Assmann
(CERN)
04/09/2007, 16:55
04/09/2007, 17:25
Raymond Veness
(CERN)
05/09/2007, 08:30
Issues Raised by the Design of the LHC Beam Dump Entrance Window
The 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...
Markus BRUGGER
(CERN)
05/09/2007, 09:00
Overview of FLUKA Energy Deposition and Design Studies for the LHC
In 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...
Markus BRUGGER
(CERN)
05/09/2007, 09:40
Generic studies of radioactivity induced by high energy beams in different absorber materials
A 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...
George SMIRNOV
(CERN)
05/09/2007, 10:35
Studies of radiation effects on graphite collimator materials
The 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...
Naeem TAHIR
(GSI)
05/09/2007, 11:00
Alessandro DALLOCCHIO
(CERN)
05/09/2007, 11:40
FE simulation of 450 GeV injection error test
Dynamic 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...
Alexander RYAZANOV
(KURCHATOV INSTITUTE)
05/09/2007, 12:05
Beam impact on collimator materials: Studies for LHC by Kurtchatov Institute
Theoretical 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...
Alessandro Bertarelli
(CERN)
05/09/2007, 14:00
FE codes for thermo-mechanical analysis for Phase I collimation
The 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...
Nick SIMOS
(BNL)
05/09/2007, 14:30
Experience with Implicit and Explicit codes in analyzing beam-induced thermo-mechanical shock
In 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,...
Luca Bruno
(CERN)
05/09/2007, 15:00
Numerical tools for the design of beam intercepting devices
Beam 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...
Rocio CHAMIZO
(CERN)
05/09/2007, 15:30
Luca Massidda
(CRS4)
05/09/2007, 15:55
Dynamic structural analysis of absorbers with spectral-element code ELSE
The 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...
Rüdiger Schmidt
(CERN)
05/09/2007, 16:35
