-
Dr Brennan Goddard (CERN)Case study: Energy deposition in superconducting magnets in IR6A diluter block TCDQ, with a collimator TCS and shield TCDQM, will be installed in front of the superconducting quadrupole Q4 magnet in IR6, to protect it and other downstream LHC machine elements from an unsynchronised beam dump. The system should also intercept particles in the abort gap to prevent quenches during regular aborts, and must also intercept the particles from the...Go to contribution page
-
Dr Vasilis Vlachoudis (CERN)Case study: Energy deposition in superconducting magnets in IR7The IR7 insertion of the Large Hadron Collider (LHC) is dedicated to beam cleaning with the design goals of absorbing part of the primary beam halo and of the secondary radiation. The tertiary halo which escapes the collimation system may heat the cold magnets at unacceptable levels, if no absorber is used. In order to assess the energy deposition in the sensitive components,...Go to contribution page
-
Verena Kain (CERN)Experiment for energy deposition in a targetMaterial damage levels for LHC intensities and energies are in general derived from computer simulations calculating static energy deposition. A dedicated experiment was carried out to cross-check the validity of this approach: With a 450GeV proton beam extracted from the SPS in TT40, material was deliberately damaged in a controlled way. A simple geometry was chosen for the high-Z...Go to contribution page
-
Dr Vincent Baglin (CERN)Heat loads from beamThe circulating beam in the LHC generates heat loads which are dissipated onto the beam screen or in the cold masses of the elements operating at cryogenic temperature. The synchrotron radiation emitted by the proton beam is intercepted by the beam screens. These beam screens are also carrying the beam image current which dissipates power. Finally, the heat load induced by the...Go to contribution page
-
Dr Rob van Weelderen (CERN)Heat transfer in superconducting magnetsUsing the present LHC inner triplets, functioning in pressurized superfluid helium, I will classify the heat extraction paths from coil until cold source and identify the limits of the present design. This will be exemplified by the measurements made using the Inner Triplet Heat eXchanger (IT-HXTU). The areas in need for improvement, when going to higher heat loads, will be...Go to contribution page
-
Prof. George Smirnov (Joint Institute for Nuclear Research)Heavy ion interactions with matterThe effects of the interaction of heavy ions with matter caused by strong electromagnetic fields produced by ultrarelativistic ions are briefly reviewed. An important feature is that electromagnetic processes compete with hadronic reactions. Moreover, in certain kinematics, like in very peripheral collisions, electromagnetic dissociation processes become dominant. The pair production...Go to contribution page
-
Dr Ralph Assmann (CERN)Introduction to the sessionThe crucial role of quench limits in LHC is pointed out and some important workshop and session goals are discussed.Go to contribution page
-
Dr Simone Gilardoni (CERN)Ion operation and beam lossesThe electromagnetic collisions of Lead ions can change the ions charge state due to electron capture via pair production (Bound-Free Pair Production ). Many electron-positron pairs are created in the intense electromagnetic fields of the nuclei. In some cases, the electron is created in a bound-state of one nucleus. These wrongly charged ions are lost in the dispersion suppressor...Go to contribution page
-
Mr Rüdiger Schmidt (CERN)LHC and magnet operationThe current of the main dipole and quadrupole magnets will ramp proportional to the momentum of the particles accelerated in the LHC, for protons from 450 GeV/c to 7 TeV/c. For those magnets, the quench margin will be largest at injection. For other magnets, the current could follow different ramps that needs to be considered for the quench margin. When the beams are squeezed to...Go to contribution page
-
Dr ranko ostojic (CERN)Insertions magnets and IR radiationThe pp collisions in the LHC interaction points generate at nominal luminosity about 900 W carried away by secondaries to each side of an experimental insertion. This energy is largely intercepted by the TAS and TAN absorbers, but a non- negligable part ends up in the coils of the superconducting low-beta quadrupoles. These magnets have to sustain and evacuate a load of...Go to contribution page
-
Dr Bertrand BAUDOUY (CEA - SACLAY)Liquid helium heat transfer in superconducting cables insulation of accelerator magnetsThe electrical insulation of superconducting cables poses the largest heat barrier between the heat exchanger and the cable for accelerator magnets. This issue is of major importance for current accelerator magnets and undoubtedly will become a critical issue for magnets subjected to a higher heat deposition. We will first present a review of heat transfer studies on the LHC cable...Go to contribution page
-
Dr Arjan Verweij (CERN)Modelling stability on Nb-Ti cables; R&D on stability planned in the Cern cable test facility FRESCAA brief overview will be given of the possibilities of modelling stability in superconducting NbTi cables. It will be shown that in many cases the accuracy of the modelling is poor (due to limited knowledge on cooling and current redistribution phenomena), so that additional experiments are needed. In the coming years, such experiments will be performed in the CERN cable test...Go to contribution page
-
Mr Guillaume ROBERT-DEMOLAIZE (CERN)Multiturn beam lossesDue to the large amount of energy stored in the LHC ring, cleaning of the beam halo is necessary in order to avoid quenches of the LHC superconducting magnets. We review the mechanisms of multi-turn beam losses and design parameters of the LHC collimation system, and present the cleaning performance for various beam lifetimes scenarios, both at injection and top energy. Results of...Go to contribution page
-
Nikolai Mokhov (FERMILAB)Protecting Superconducting Magnets from Radiation at Tevatron, SSC, LHC and its upgrades.The principal challenges arising from beam-induced energy deposition in superconducting magnets at hadron colliders are described. Radiation constraints are analyzed that include quench stability, dynamic heat loads on the cryogenic system, radiation damage limiting the component lifetime, and residual dose rates related to hands-on maintenance. These issues are especially challenging...Go to contribution page
-
Dr Andrzej Siemko (CERN)Quench levels – experience from magnet tests at CERNWhen does the magnet quench? MQE and MPZ concept Is it relevant for beam induced quenches? Quench levels of various families of the main ring superconducting magnets Outlook on further simulations and envisaged experiments ConclusionsGo to contribution page
-
Kay Wittenburg (DESY)Quench levels and transient beam losses at HERAThe talk recalls the main parameters which defined the expected beam loss generated quench levels (in 1985) and compares the results with measurements of loss induced quenches at HERA during 1994-2005. The parameters of the BLM system are discussed (like calibration, positioning, alarm level, etc.) and the response of the system to beam loss induced quenches with different time...Go to contribution page
-
Mr luca bottura (CERN)MEB and magnet sorting criteriaThe allocation of magnets at MEB is presently following guidelines on sorting derived from quench training curves. These guidelines are based on working assumptions rather than well established results. The presentation lists the open questions to be resolved for a sound sorting.Go to contribution page
-
Dr Daniel Leroy (CERN)Review of past estimations of the induced quench levels by beam losses in the LHC dipoles
-
Dr Marco Calvi (CERN, AT Department, MTM group)SPQR – could it contribute?The thermal and electrical equations implemented in SPQR code are presented and possible improvements underlined. The approach used to numerically solve them is briefly recalled and the technique adopted to calculate the minimum quench energy (MQE) clarified. Examples of MQE calculations are presented for different space and time perturbations and the minimum propagation zone (MPZ)...Go to contribution page
-
Dr Alexander Zlobin (Fermilab)Thermal analysis and its experimental verification for the present and future IR tripletsThe first generation of low-beta quadrupoles for the LHC IR inner triplets based on NbTi superconductor was developed by KEK and Fermilab in collaboration with CERN. The magnets were designed to achieve the nominal luminosity of 10^34 cm^- 2s^-1. They provide a nominal field gradient of 200 T/m with a 20% margin at the high luminosity insertions with 70-mm coils, and operate at 1.9K...Go to contribution page
-
Dr Francesco Broggi (INFN - LASA Lab.)Thermal modelling of IR quadrupolesAbstract – In this talk is presented the work carried out at LASA Laboratory in the years 1995 - 1999, related to the design of a new type of quadrupoles for the LHC low-beta insertion based on Nb3Sn technology. The work deals of the power generated into the insertion quads from the reaction products of the 7TeV p-p collision in the high luminosity interaction point of LHC. The...Go to contribution page
-
Dr Brennan Goddard (CERN)Transient beam losses at injection and during beam dumpThe injection and beam dump processes are designed to avoid any beam losses. However, situations will occur in which these processes are not carried out correctly, for instance with out of tolerance beam characteristics, wrong settings or equipment failures. In these cases beam losses can occur. Damage to accelerator equipment should be prevented by the Machine Protection systems,...Go to contribution page
-
Mr David Richter (CERN)Understanding AC losses for LHC magnetsBrief comparison of results of the direct heat transfer measurement done on stacks of cables by B. Baudouy, L. Burnod, D. Leroy, C. Meuris, and B. Szeless with corresponding results based on the ramp rate limitation of the first LHC model dipoles by A. P. Verweij, in the period 1991-99.Go to contribution page
-
Bernd Dehning (CERN)Why do BLMs need to know the quench levels?The LHC beam loss monitoring system is based of the detection of secondary shower particles, which depose their energy in the accelerator equipment and finally also in the monitoring detector. To protect the equipment and to prevent quenches the likely loss locations have to be identified by tracking simulations or by using low intensity beams. To keep the operational efficiency...Go to contribution page
Choose timezone
Your profile timezone: