200 likes | 386 Views
WP4 : Beam Line Design. Deepa Angal-Kalinin ASTeC, Daresbury Laboratory On behalf of WP1.1+ WP1.2 (LC-ABD1) + WP4.1 (LC-ABD2) team. LC-ABD2 Plenary Meeting, 24 th September 2007, Liverpool. LC-ABD2 WP4 : Beam Line Design. LC-ABD1 WP1.1 +WP1.2 + WP5.3.
E N D
WP4 : Beam Line Design Deepa Angal-Kalinin ASTeC, Daresbury Laboratory On behalf of WP1.1+ WP1.2 (LC-ABD1) + WP4.1 (LC-ABD2) team LC-ABD2 Plenary Meeting, 24th September 2007, Liverpool
LC-ABD2WP4 : Beam Line Design LC-ABD1WP1.1 +WP1.2 + WP5.3 4.1 BDS Lattice Design and Simulations (distribution of simulations) 4.2 BDS Collimator design 1.1 Lattice Design & Beam Simulations 1.2 BDS beam transport simulations (lattice design, laser wire, feedback, beam halo, collimator wakefields and electromagnetic backgrounds) 5.3 Collimation Luis
BDS Lattice Design • Pre-technology decision • Efforts concentrated on TESLA BDS Design • Final focus • Collimation and diagnostics • Difficulties to extract the disrupted beam at 800 GeVCM • Post-technology decision • NLC BDS design dominated • ILC with two IRs was the baseline, no design for small IR • NLC lattice adapted for survivable collimators • Efforts mainly concentrated on developing the small crossing angle IR and extraction line design • Lattice optimisation study for collimation performance • Evaluation of BDS collimation depths with evolving machine configurations and machine parameters • Development of beam diagnostics optics for laser wire • Optics support for beam tests at ESA
BDS configuration changes : First ILC workshop(Nov’04) till July’06 BDS layout configuration till July 2006 RDR BDS configuration with 1 IR 14 mrad
BDS Collimation Optics Design Collimated halo after optimisation Collimated halo before optimisation • Lattice optimisation demonstrates significant improvement in collimation efficiency • Collimation depths for different detector concepts, different L* covering all the parameter ranges of the ILC Collimation depths : ILC reference design report F. Jackson
Emittance Tuning Simulations Developed a robust integrated simulation environment for analysis of various methods of beam tuning simulations. Simulation structure works for both ILC and ATF2 with minimal changes. Investigated traditional and more novel methods of beam tuning on ILC and ATF2. Analysis shows viable methods can be created to remove the emittance dilution effects as seen at the IP, using only the final 5 sextupole magnets. Performed further investigations into the linearity of such tuning knobs, and the limits with position and field errors on the tuning magnets. Performed tolerance studies on both the ILC and ATF2 including the effects of trajectory correction. J. Jones, A. Scarfe
BDSIM Development • Beamlines are built of modular accelerator components • Full simulation of EM showers • All secondaries are tracked • BDSIM was used extensively for the ILC BDS simulations. • Benchmarking tests were performed for particle tracking, electromagnetic and hadronic physics processes • The BDSIM distribution was deployed on the GRID to increase the performance • Full IR Geometry modelled in BDSIM • Includes a full Solenoid Field Map Screenshot of an IR Design in BDSIM I. Agapov, J. Carter, S.Malton
Losses in ILC extraction linecalculated with BDSIM 100W/m hands-on limit 20mrad Losses are mostly due to SR. Beam loss is very small 2mrad 250GeV Nominal, 0nm offset 100W/m 45.8kW integr. loss Losses are due to SR and beam loss J. Carter
BDSIM Development Being used for background calculations, also for laser-wire signal extraction: ILC polarimeter chicane ATF2 extraction line positron dipole LW photon quadrupoles BPMs beam pipe window dipoles electron quadrupoles LW exit port LW photon Also developing an interface to PLACET, for collimator wake-field studies S.Malton, L. Deacon
Recreate ILC-like background hits on BPM • Developed a simulation of the noise on the IP feedback BPM striplines caused by secondary Electromagnetic shower products that result from beam-beam primaries striking the material inside of the inner IR region. Significant GEANT modelling. • Simulated expected noise at ESA T488 experiment, which attempted to mimic the EM environment at ILC Christine Clarke’s talk in WP7 BPM1 s.e. Q = -2297 Incident beam spot BPM2 s.e. Q = -2057 BPM4 s.e. Q = -1908 BPM3 s.e. Q = -2848 A. Hartin
Laser wire : Measurement precision The Goal: Beam Matrix Reconstruction NOTE: Rapid improvement with better σy resolution Reconstructed emittance of one train using 5% error on σy Assumes a 4d diagnostics section With 50% random mismatch of initial optical functions The true emittance is 0.079 m rad I. Agapov, G.Blair, M.Woodely
IP intra-train FB performance G. White position (or angle) scans gain additional luminosity angle scan position scan using luminosity signal IP position FB J. Lopez angle scan marginal luminosity gain from scans (?) position scan using luminosity signal IP position FB
End Station A Optics vertical beam size 83m for collimator wakefield tests • Major ILC test facility • Challenges • Varied optics demands • Strong bends (dispersion suppression, synchrotron radiation) • Able to achieve small horizontal and vertical beam sizes horizontal beam size 240m for BPM studies F. Jackson
Luminosity loss due to wake fields MERLIN PLACET & GUINEA-PIG A. Bungau A. Toader
3 warm bends QF, SF warm quad & sext 2 “Panofsky” quads dump(s): 0.5 m 3 m QD, SD NbTi (Nb3Sn) SC kickers BB1,2 BHEX1 FD collimators Length ~ 300 m New “minimal” extraction line concept • Snowmass 2 mrad design unsatisfactory redesign with simpler concept aiming to be as short & economical as possible • Assumption : other ways than the present spent-beam spectrometry & polarimetry are possible to complement pre-IP measurements R. Appleby et al
14 mrad baseline extraction optics With detector field Without detector field y offset (600 µm) y’ offset (12 µrad).The number of particles inside the laser spot ±100 µm is 0.1% of its number at IP. The number of particles inside the laser spot ±100 µm is 44% of its number at IP • To compensate the detector effect and to increase the number of particles inside the laser spot size. • Include anti-solenoid, anti-DID (for different detector concepts) • Include magnetic and beam errors to study the diagnostics performance and effect on beam losses at collimators D.Toprek, R. Appleby
z=4m z=7.3m z=9.3m z=12.5m IR vacuum design solution Tubes are TiZrV coated Tubes are TiZrV coated QF1 cryostat cold bores, 2K QD0 cryostat cold bores, 2K Be part incoming 0.2m ~4m Beam screen with holes to avoid H2 instability Pumps connected to the tubes close to the cone Legend: pump bellows BPM, strip-line valve kicker, strip-line flanges O. Malyshev ; original sketch of IR region by A.Seryi
What did we achieve in last 3 years? • Strong optics and simulation core group : BDS and extraction line lattice design and simulations • Key role in 2 mrad design • Comparison of this design with 20 mrad has lead to currently proposed 14 mrad design with anti-DID • Significant contributions to start-to-end simulations Feedback • Collimation depths and optics optimisation for better collimation efficiency • Effects of collimator wake fields on beam, simulations for ESA beam tests WP5.3 • A complete full simulation tool BDSIM and benchmarking with other codes • Simulations for beam diagnostics optics using laser wire • Electromagnetic backgrounds simulations • Tuning algorithms and procedures for ILC/ATF2 • Optics support for ESA test experiments • Significant contributions to the RDR
Ongoing and planned studies : LC-ABD2 • Performance evaluation of 14 mrad baseline • Develop BDSIM for detailed analysis of extraction line losses and back scattering • Develop full optics simulations of skew correction and emittance measurement section with realistic errors • Complete study of alternative extraction schemes and document • Optimisation of collimation optics, include realistic machine and beam errors • ATF2 : simulations and beam tests • Calculate the average pressure and pressure profiles in the BDS and the extraction lines • Decide on the choice of material for the BDS vacuum systems • Beam line integration • Optics support for ESA (or any other test facility) The work programme fits very well into the evolving WBS for BDS EDR
Summary • LC-ABD team has developed a skill base within UK for BDS lattice design and simulations • Strong collaborations with LAL, CEA, SLAC, FNAL, KEK, CERN • Much more studies, simulations and engineering design details are planned for the EDR phase. • Look forward to implementing and testing these studies at ATF2 and other test facilities