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WEOCAB02 | Automatic Luminosity Optimisation of the ILC Head-On BDS | 1988 |
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Funding: EUROTeV Project Contract no.011899 RIDS
With the local chromaticity correction scheme, the luminosity optimisation of the beam delivery systems of the e+ e- International Linear Collider (ILC) project is challenging. A manual optimization is a long and complex process and its automation becomes a necessity. Recent works have shown that it was possible to employ a simplex minimization method, applied to the beam size calculation at the Interaction Point (IP), to reach this objective automatically *. To achieve this goal in the ILC case, we have developed a minimization code which uses analytical computations of the IP beam sizes based on external code results, TRANSPORT** or MADX (with PTC extension)***. Two minimization algorithms can be employed. The maximum luminosity reached and the convergence time of the two codes and algorithms are compared. We also used the code TRACEWIN which tracks a particle cloud and minimise the rms beam spot sizes at IP to optimise the luminosity, and we compare with the previous results.
* Non-linear optimization of beam lines, R. Tomas, CLIC Note 659** Third-Order TRANSPORT with MAD Input, D. C. Carey, K. L. Brown and F. Rothacker, FERMILAB-Pub-98/310*** MADX User's Guide CERN |
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THPMN008 | Evaluation of Luminosity Reduction in the ILC Head-on Scheme from Parasitic Collisions | 2722 |
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An interaction region with head-on collisions is being developed for the ILC as an alternative to the base line 14 mrad crossing angle design, motivated by simpler beam manipulations upstream of the interaction point and a more favourable configuration for the detector and physics analysis. The design of the post-collision beam line in this scheme involves however a number of technological challenges, one of which is the strength requirement for the electrostatic separators placed immediately after the final doublet to extract the spent beam. In this paper, we examine in detail the main mechanism behind this requirement, the multi-beam kink instability, which results from the long-range beam-beam forces at the parasitic crossings after the bunches have been extracted. Our analysis uses realistic bunch distributions, the Guinea-Pig program to treat beam-beam effects at the interaction point and the DIMAD program to track the disrupted beam distributions in the post-collision beam line. A version of the beam-beam deflection based interaction point feedback system with an improved filtering algorithm is also studied to mitigate the luminosity deterioration from the instability. | ||
WEOCAB01 | Design of the Beam Delivery System for the International Linear Collider | 1985 |
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The beam delivery system for the linear collider focuses beams to nanometer sizes at the interaction point, collimates the beam halo to provide acceptable background in the detector and has a provision for state-of-the art beam instrumentation in order to reach the physics goals. The beam delivery system of the International Linear Collider has undergone several configuration changes recently. This paper describes the design details and status of the baseline configuration considered for the reference design. | ||
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THPMN005 | Technical Challenges for Head-On Collisions and Extraction at the ILC | 2716 |
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Funding: EUROTeV Project Contract no.011899 RIDS An interaction region with head-on collisions is considered as an alternative to the baseline ILC configuration. Progress in the final focus optics design includes engineered large bore superconducting final doublet magnets and their 3D magnetic integration in the detector solenoids. Progress on the beam separation optics is based on technical designs of electrostatic separator and special extraction quadripoles. The spent beam extraction is realized by a staged collimation scheme relying on realistic collimators. The impact on the detector background is estimated. The possibility of technical tests of the most challenging components is investigated. |
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FRPMN011 | Studies of Dipole Field Quality for the Beta-Beam Decay Ring | 3904 |
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Funding: European Community under the FP6 - Research Infrastructure Action - Structuring the European Research Area - EURISOL DS Project Contract no. 515768 RIDS. The aim of the beta-beams is to produce highly energetic beams of pure electron neutrino and anti-neutrino, coming from beta-decays of the 18Ne10+ and 6He2+, both at γ=100, directed towards experimental halls situated in the Frejus tunnel. The high intensity ion beams are stored in a ring until the ions decay. The beta decay products have a magnetic rigidity different from the one of the parent ions and are differently deflected in the 6T superconducting dipoles. Consequently, all the injected ions are lost anywhere in the ring, generating a high level of irradiation. So, the dipole apertures need to be large enough to avoid the decay products hitting their walls, which may worsen the field quality. A study on its tolerances has been carried out. Since the decay ring has to accept the beam during a large number of turns, the chosen criteria is the size of the dynamic aperture that the multipolar defects in the dipoles may shrink. Tolerances on the systematic and random errors of these defects have been investigated. In order to relax the tolerances, a routine was written which enlarges automatically the dynamic aperture in presence of field errors. |