1. Extraction line and beam dumps summary ILC European Regional Meeting and ILC-BDIR Royal Holloway, 23rd June 2005 Rob Appleby ASTeC, Daresbury Laboratory

2. BDS optics & layout I : Tuesday 21 st June Design of 2 mrad extraction line – R. Appleby Design of 20 mrad extraction line – A. Seryi Extraction and Dumps I : Wednesday 22 nd June Approaches to a high power beam dump for(TESLA 800 GeV like) ILC – M. Schmitz Beam dump considerations from the US – T. Markiewicz Extraction and Dumps II + FF : Wednesday 22 nd June Extraction line diagnostics – E. Torrence

3. International BDS group is working hard to turn the Strawman tentative configuration into real design: Full optics for all beamlines; Well developed and optimized 20mrad optics and magnets design; Created the method and made several iterations of optics and magnets for 2mrad IR; Upstream and downstream diagnostics for both IRs 1 st ILC Workshop November 2004

4. 20mrad IR, extraction & compact SC quads Based on compact SC quads BNL => even tighter bend radius => quad is more compact => allow to place extraction quad with ¼ gradient near QD0 Extraction line design use this advantage => extraction quad has same L*as QD0 QDEX1 also serves as compensator of QD0 field 18 m Incoming beam Disrupted beam QFEX2QDEX1 QD0 SD0 QF1 Warm -><- SC Crab cavity Talk by A. Seryi

5. Latest optics Increased distance to dump (200m=>340m) to increase undisrupted beam size Two round collimators with r = 8.8 cm and 13.2 cm at 200m and 300 m Talk by A. Seryi

6. Disrupted beam losses for 20mrad extraction line Collimators 1 and 2 are at s=200m and 300m and have round aperture of r=8.8cm and 13.2cm, to reduce beam size at the dump (round window r<15cm) Talk by A. Seryi

7. 2 mrad Crossing angle – Extraction line design Features of optimised design Extracted electrons and photons pass at crossing angle through the aperture of the incoming QD0 and SD0, SF1 sextupoles and through the pocket aperture of the QF1 quadrupole. Shared magnets need large aperture to accept both electron beams and photons. Final doublet optimised for incoming and outgoing beam. QD0 SD0QF1 SF1 T. Maruyama SLAC-BNL-UK-France task force Several design iterations since Nov’04 QD0 radius 45mm, length to 4.0m -> "long" doublet QD0 radius 35mm, length to 2.5m -> “short” doublet Talk by R. Appleby

8. 2mrad extraction line with diagnostics chicane Plot from Yuri Nosochkov Talk by R. Appleby

9. Full line to dump for 500 GeV machine short doublet Downstream diagnostics worked out for 500 GeV machine, for a variant of the short doublet. Turtle tracking studies show good beam transport Talk by R. Appleby

10. Diagnostics chicane for 2 mrad Diagnostics chicane for 20 mrad Talk by E. Torrence on behalf of Ken Moffeit

11. Introduction ABSORBER WINDOW Thermal and Mechanical Issues  heating and heat extraction  stresses and pressure Radiochemical Aspects  radiolysis, dissociation Radiological Issues  handling of induced radioactivity  shielding of direct radiation BEAM SWEEPING Distribution of Beam on Absorber  intra bunch train (fast sweep)  average power (slow sweep) Separation of beam vacuum and absorber TtTt repitition time 1/ν rep e- or e+ with E 0 bunch train with N t particles Beam to be dumped (TESLA 800 parameters) E 0 =400GeV, N t =6.84·10 13 e-, T t  1ms, ν rep =4Hz  pulsed power source with W t =4.4MJ per train P ave =17.5MW in average Talk by M. Schmitz

12. Solid Dump: Heat Extraction  capture 400 GeV shower  longitudinal:  5m, transversal: 1R m (C)+3R m (Cu)=7cm+5cm  E 0 =400GeV, P ave =17.5MW  I ave =44  A  (dP/dz) max  75kW/cm ! How to get rid of ? 75kW/cm  15m ! slow sweep  tot  0.12W/(cm 2 ·K) and (dP/dz) max =  tot ·w ·(ΔT eq ) max allow (ΔT eq ) max  400K (prevent oxidation of C)  w  20cm / (kW/cm) · (dP/dz) max C-based absorber embedded in Cu  huge and heavy absorber  huge vacuum system  complicated slow beam sweeping  C-Cu Approach not suitable only reasonable for (dP/dz) max  kW/cm  P ave  100kW level 5cm Cu 7cm C 5cm Cu w z cooled surfaces beam, linear sweep of length w heat flow ΔT eq Heat extraction by transverse heat conduction and sweeping 2m 8 sandwiches of 25cm = 2m  5m beam Discussion Talk by M. Schmitz

13. water-system air treatment water-dump vessel dump shielding enclosure emergency/comm. beam tilted  15mrad spent beam, tilted  15mrad hall basin exhaust / chimney? sand normal cooling water Water Dump: Overall Scheme Talk by M. Schmitz

14. Gas Dump: First Thoughts One atomic noble gas core (Ar, Xe) is surrounded by solid material (Fe)  gas core acts as scattering target (only small amount of energy deposition) and distributes energy longitudinally over ~ 1km into surrounding material  low energy densities, no sweeping, small spot size possible, no radiolysis  surrounding material takes main part of energy Z  20  reduced tritium production Basic Idea Energy density (1 electron 400GeV), dE/dV [GeV/cm 3 ] r-bin=1cm, z-bin=10m r [cm] z [m] First Attempt (not optimized) water, 4cm Ar core,  8cm @ normal conditions Fe, 52cm thick air tunnel gas dump  1.2m, ~1km Talk by M. Schmitz

15. Comparative Summary Graphite-Copper DumpWater DumpNoble Gas Dump 2m x 2m, 5m long  1.5m, 10m long  1.2m, 1km long (extra? tunnel) heat conductivity & immense slow sweep adequate water flow no slow sweep heat conductivity no slow sweep radiation degradation of heat conductivity of graphite ? explosive radiolysis gases in a highly activated system no dissociation of one atomic gas cyclic stress in C tolerabletransient pressure in watergas buffers transient expansion window  2m unless not put upstream of sweeping vac./water window  20cm challenging design vacuum/gas window  8cm design ~exists need increased spot size (fast sweep) to limit energy density applicable for smaller spot sizes and therefore as γ/γ-dump total tritium inventory  300TBq tritium inventory factor 10 less and 98% bound in a solid  30% in water, rest in C-Cu all in water maintenance complicatedeasier maintenance high activated components, dismantling costs not negligibleactivation of 1km tunnel Technically not practicable for high power applications Principally feasible, but inherent risks will make it difficult to „sell“ it as reliable, safe and robust. Attractive new idea, which should be investigated in more detail Talk by M. Schmitz

16. 2 mrad Extraction Layout Note proximity of beamstrahlung dump to the incoming beam – may need to put the incoming beam line pipe through the water tank. Talk by T. Markiewicz on behalf of L. Keller

18. Talk by V. Ziemann

19. Talk by O. Dadoun

20. Extraction line road to Snowmass and beyond For Snowmass Decide doublet layout for 2mrad scheme, in conjunction with magnet experts (See Deepa's summary talk). Fix extraction line optics by, say, 14th July Construct layout of 2mrad scheme, including diagnostics and beam transport to dump, for TeV machine. Compare 2mrad and 20mrad extraction lines Longer timescales: impact of parameters on performance Diagnostic performance, radiation backgrounds etc. finalize baseline configuration at the end of 2005 Ongoing engineering design will continue and mature Detailed specs for engineering Done during 2006. CDR with cost in Dec.2006

21. Beam dump road to Snowmass and beyond This meeting has given serious time and attention to this crucial aspect of the ILC. We need to learn from the fantastic work of the past, and figure out how to make it work for our machine. Currently two designs: Water based dump - should be considered baseline Gas dump - perhaps should be considered option For Snowmass: Need to define critical areas for study Dump window Beamstrahlung and tuning dumps Overall integration into layout Work out who will look at them This process is now underway!

22. ILC Beam Delivery System Pre-Snowmass Reference Design Report (DRAFT) The Reference Design Report is based on assumption of two interaction regions. It is understood that particle physics output and cost of two IRs vs single IR will be evaluated in details. BDS BaselineBaseline R&DOption and Option R&D One of IRs with 20+mrad crossing, separate incoming and extraction lines Many. See specific items below.15-25mrad One of IRs with ~2mrad crossing, first FD magnets shared Many. See specific items below.Head-on with electrostatic separator or RF kicker; Or same 20mrad for 2 nd IR Compact SC direct wind quads for 20mrad, separate cryostats for QD0 & QEXF Prototype compact SC QD0Common cryostat SC quads, other technology? FF optics based on local chromatic correction Get experience with compact FF at AFT2Traditional FF with non- interleaved sextupole pairs 2mrad extraction beamline with E and polarization diagnostics, with separation of e+- and  after first extraction line doublet Prototype SC super septum quads or Panofsky style septum quads Other ideas for magnets? Large bore SC magnets for 2mrad, minimal external size, with antisolenoid and movers inside? Prototype needed?Alternative SC materials which allow larger aperture, but brittle in manufacturing Crab cavity based on 1.3 or 3.9GHz located near FD in 20mrad IR and near SD4 in 2mrad IR Prototype crab cavity with proper damping of high order modes Crab cavity based on 1.3GHz SC RF, or warm RF cavity Main beam dumps based on water vortex scheme rated for 18MW beam. Common e+- and  dump for 20mrad, separate  dump for 2mrad Separate beam dumps full power for all beamlines. Undisrupted beam size increased by distance. Prototype and tests of beam dump window?Elliptical wide window. Gas beam dump (1km of Ar in Fe). Beam sweeping and/or graphite rod. Betatron collimation based on collimation in FD and IP phase, with survivable spoilers Measurements of collimator wakefields. Beam damage studies at ESA. Betatron collimation with consumable spoilers. Their prototype. IR magnet support with passive vibration protection IR prototype at ESAActive stabilization of FD support Antisolenoid as part of detector in 20mrad IRDo we need prototype or design studies sufficient? No antisolenoid, only skew quad correction Antisolenoids as part of large bore QD0Prototype QD0, solve decoupling force on solenoid from the quad No antisolenoid, only skew quad correction Detector solenoid with Detector Integrated Dipole for both 20mrad and 2mrad Design studies sufficient, no prototypesNo DID Incoming beamline BPMs are cavity based submicron resolution Prototype large aperture cavity BPMsStripline BPMs? Diagnostics with orthogonal coupling correction section followed by a 4-wire- scanner 2D (projected) emittance measurement section with laser wire system with beam sizes > 17*1.5 microns Prototype laser wire at PETRA and ATF/ATF2, achieve needed resolution of micron beam Lengthened diagnostics section with larger beam sizes at laser wire scanners Fast intra-train digital feedback system with BPMs on the IP face of FD and kickers near FD Prototype intratrain feedback at ATF and ATF2, beamtest of BPMs in background conditions at ESA No other options? Analog feedback is an option? FD movers for 2mrad IR: movers are located inside of the cryostats of the large aperture magnets. Prototype the movers. Piezo or magnetostrictive technology? Other techniques? FD movers for 20mrad IR: mechanical movers for each magnet individually, located outside cryostats, based on FFTB scheme Prototype at ESA: IR mockup?Other techniques? Energy spectrometer based on high resolution cavity BPMs with variable chicane for upstream beamlines Prototype at ESA for BPMs, precise magnets, movers, survey system Polarimeter for upstream beamlines Downstream energy spectrometer based on synchrotron stripe monitor Prototype at ESA Collider halls separated by about hundred meters longitudinally, size w*l*h meters Mover system for main beamline magnets based on FFTB scheme Mover system based on 6D movable system (SBIR 1, possible SBIR 2) Tail folding octupoles based on SC magnets with five magnets in each FF branch Prototype strong octupoles Muon and personnel protection wall based on magnetized iron, two per FF branch, 9m and 18m long Single muon protection wall may be sufficient for lower halo population and higher tolerance for muon background Emittance diagnostics and correction system upstream of beam switchyard, common system for both IRs Separate diagnostics in each branch? Fast luminosity and pairs monitors based on … technology… Prototype and test at ESA IR with cryo-pumping by cold bore magnets IP BPMs … BDS Reference Design Report for Snowmass