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## Model of Magnets in the Decay Ring

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**Model of Magnetsin the Decay Ring**E. Bouquerel & FLUKA Team, CERN (EN-STI-EET) EUROnu, 3rd WP4 - Beta Beam - Task Meeting 25th November 2009, Grenoble**Reminder(EURISOL DS FP6…)**Magnet studies achieved on the Straight Section of the Decay Ring (where Collimation occurs) Average Power deposited due to collimation approaches: 74 kW (55% of the injected 9x10126He2+ particles) 230 kW (80% of 4.26x1012 particles for the 18Ne10+) Use of superconducting magnets NOT possible due to high intensity to collimate (quenching issues) use of warm dipoles/quadrupoles**Tracking Simulations**Losses due to collimation generated with ACCSIM code (F. Jones; P. Delahaye): To perform the first stages of modeling the trajectory of the ions (from their injection to the collimation process) Generation of an output file containing: Turn number, Element number, Particle number, Even type, Longitudinal position (coordinates), Event and transverse coordinates. ACCSIM output file used as a source file for FLUKA simulations + implementation with a 3D geometry of one of the Straight Section of the DR components and physics models for ion interactions in matter**Geometry Implementation (FLUKA)**Dipol. Qdrupol. Collim. Vertical axis (cm) beam Beam pipe 2nd Bump tunnel Straight Section, beam axis (cm)**Geometry Implementation (FLUKA)Dipoles**Implementation of 5 warm dipoles in the Straight Section + in the 2nd bump**Geometry Implementation (FLUKA)Dipoles**Only abritrary model for warm dipoles needed for collimation studies (FP6) L=12m 600m 20 mrad y z x 500 300 1000 Cu 85 500 z Fe 100 Inspired from C-shaped magnet Diamond and SESAME storage rings 200 y**Geometry Implementation (FLUKA)Quadrupoles**Cu Implementation of 25 standard warm quadrupoles in the Straight Section and the 2nd bump Fe 2m long 30cm 90mm aperture**Power Deposited / Doses Absorbed(FLUKA)**Coordinate along the straight axis (cm) GeV/cm3/prim. lost Between 18-20% of the incoming power deposited along the Straight Section, mainly on the quadrupoles/dipoles located after each collimator**Power Deposited / Doses Absorbed(FLUKA)**Quadrupoles • average power deposited: acceptable • dose absorbed by the coils: NOT acceptable Dose limitation for warm elements: 10 MGy Absorbers needed Dipoles**Power Deposited / Doses Absorbed**• Five carbon absorbers added in FLUKA: • 100 cm long • 50 cm diameter • 8.3 cm diameter aperture (SimpleGeo view)**Doses Absorbed (FLUKA)**Quadrupoles no abs. Dose absorbed decreased by factor 3 to 5 with abs. Dipoles no abs. Dose absorbed decreased by factor ~4 with abs.**Doses Absorbed (FLUKA)**Quadrupoles no abs. Dose absorbed decreased by factor 3 to 5 with abs. • Dose absorbed still too high: • can stand a 3-year-operation of the DR before changing them addition of more absorbers? Dipoles no abs. Dose absorbed decreased by factor ~4 with abs. Preliminary values!!**Next Steps/Possibilities**Coupling ACCSIM/FLUKA to get a better accuracy in the patterns of the collimated ions at each turn achieved in the DR ISOCIM/FLUKA being successfully tested SPS Scrapers (V. Vlachoudis, F. Cerutti, CERN) Addition of absorbers to avoid magnet changes after 3-year-operation (reach a total dose absorbed < 10 MGy) Quadrupoles/Dipoles more detailed in FLUKA (assumptions for materials): Yoke: could equally be steel Cu windings: with water cooling and epoxy resin/ glass cloth Could change significantly the pattern of the absorbed dose by the magnets! • Increase the aperture of the quadrupoles • Any suggestion welcome!**References**• F.W. Jones, G.H. Mackenzie, and H. Schonauer, “ACCSIM – A Program to Simulate the Accumulation of Intense Proton Beams,” 14th Int. Conf. on H. E. Accelerators, Tsukuba, Japan, 1989, in Particle Accelerators 31:199 (1990). • "The FLUKA code: Description and benchmarking“ G. Battistoni, S. Muraro, P.R. Sala, F. Cerutti, A. Ferrari, S. Roesler, A. Fasso`, J. Ranft, Proceedings of the Hadronic Shower Simulation Workshop 2006, Fermilab 6--8 September 2006, M. Albrow, R. Raja eds., AIP Conference Proceeding 896, 31-49, (2007) "FLUKA: a multi-particle transport code“ A. Fasso`, A. Ferrari, J. Ranft, and P.R. Sala, CERN-2005-10 (2005), INFN/TC_05/11, SLAC-R-773 • SimpleGeo, Theis C., Buchegger K.H., Brugger M., Forkel-Wirth D., Roesler S., Vincke H., "Interactive three dimensional visualization and creation of geometries for Monte Carlo calculations", Nuclear Instruments and Methods in Physics Research A 562, pp. 827-829 (2006).