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 4.1 BDS Lattice Design and Simulations (distribution of simulations) 4.2 BDS Collimator design LC-ABD1 WP1.1 +WP1.2 + WP 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 GeV CM 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 Lattice optimisation demonstrates significant improvement in collimation efficiency Collimation depths for different detector concepts, different L* covering all the parameter ranges of the ILC Collimated halo before optimisation Collimated halo after optimisation 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 Screenshot of an IR Design in BDSIM Full IR Geometry modelled in BDSIM Includes a full Solenoid Field Map I. Agapov, J. Carter, S.Malton

100W/m hands-on limit Losses are mostly due to SR. Beam loss is very small 100W/m Losses are due to SR and beam loss 20mrad 2mrad Losses in ILC extraction line calculated with BDSIM 250GeV Nominal, 0nm offset 45.8kW integr. loss J. Carter

ATF2 extraction line ILC polarimeter chicane LW photon dipoles quadrupoles positron electron BPMs LW photon LW exit port quadrupoles dipole beam pipe window BDSIM Development Also developing an interface to PLACET, for collimator wake-field studies Being used for background calculations, also for laser-wire signal extraction: S.Malton, L. Deacon

Recreate ILC-like background hits on BPM BPM1 s.e. Q = BPM2 s.e. Q = BPM3 s.e. Q = BPM4 s.e. Q = Incident beam spot A. Hartin 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

Laser wire : Measurement precision NOTE: Rapid improvement with better σ y resolution Reconstructed emittance of one train using 5% error on σ y Assumes a 4d diagnostics section With 50% random mismatch of initial optical functions The true emittance is  m  rad The Goal: Beam Matrix Reconstruction I. Agapov, G.Blair, M.Woodely

IP position FB position scan angle scan using luminosity signal position (or angle) scans gain additional luminosity IP intra-train FB performance IP position FB position scan angle scan using luminosity signal marginal luminosity gain from scans (?) G. White J. Lopez

End Station A Optics Major ILC test facility Challenges – Varied optics demands – Strong bends (dispersion suppression, synchrotron radiation) Able to achieve small horizontal and vertical beam sizes vertical beam size 83  m for collimator wakefield tests horizontal beam size 240  m for BPM studies F. Jackson

Luminosity loss due to wake fields MERLIN A. Bungau PLACET & GUINEA-PIG A. Toader

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 New “minimal” extraction line concept Length ~ 300 m dump(s): 0.5 m 3 m QF, SF warm quad & sext QD, SD NbTi (Nb3Sn) SC FDFD 3 warm bends 2 “Panofsky” quads collimators kickers BHEX1 BB1,2 R. Appleby et al

The number of particles inside the laser spot ±100 µm is 44% of its number at IP 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. Without detector field With detector field 14 mrad baseline extraction optics 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

QD0 cryostat cold bores, 2K QF1 cryostat cold bores, 2K ~4m z=4mz=7.3mz=9.3mz=12.5m incoming 0.2m Be part Legend: pump BPM, strip-line flanges kicker, strip-line valve bellows IR vacuum design solution Tubes are TiZrV coated Pumps connected to the tubes close to the cone Beam screen with holes to avoid H 2 instability 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

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 Summary