Post on 05-Jan-2016
Andrei Seryi ILC BDS, DOE review 1 June 2005
The ILC Beam Delivery System, ATF2 and ESA
Andrei SeryiSLAC
DOE High Energy Physics Program Review
June 14-15, 2005
Andrei Seryi ILC BDS, DOE review 2 June 2005
The scene• Truly international efforts with more than 100 people
are involved in machine and machine-detector aspects of BDS– Daresbury, RHUL, QMUL, Oxford, UCL, LAL, CEA/Saclay, CERN,
BINP, DESY, INFN, …– KEK, Tokyo University, Kyoto ICR, IHEP, Pohang AL, …– SLAC, BNL, Fermilab, LLNL, Universities, … and many other …
• SLAC contribution need to be viewed in this context
• Experience of BDS design and operation is one of biggest strength of SLAC – Design and work with SLC Final Focus, instrumentation & MDI
aspects– Dedicated international Final Focus Test Beam facility
• ILC BDS design – Working Group 4 of ILC– conveners: Grahame Blair, Tomoyuki Sanuki, Andrei Seryihttp://www-project.slac.stanford.edu/ilc/acceldev/beamdelivery/
Andrei Seryi ILC BDS, DOE review 3 June 2005
Mature design of BDS; large role of SLAC
• Final Focus of SLC design with chromaticity correction by interleaved sextupoles
• Non-interleaved (for x and y planes) sextupole pairs – verified at FFTB
• The lessons learned at these facilities => FF with local chromaticity correction, designed at SLAC for NLC in 2000, now the basis of ILC BDS
• Designs for the IR, BDS instrumentation and beam dumps follow the lessons learned at SLC and are the basis for ILC
NLC BDS~2002
Andrei Seryi ILC BDS, DOE review 4 June 2005
Beam Delivery System challenges• Focus the beam to size of about 500 * 5 nm at IP • Provide acceptable detector backgrounds
– collimate beam halo
• Monitor the luminosity spectrum and polarization– diagnostics both upstream and downstream of IP is desired
• Measure incoming beam properties to allow tuning of the machine
• Keep the beams in collision & maintain small beam sizes – fast intra-train and slow inter-train feedback
• Protect detector and beamline components against errant beams
• Extract disrupted beams and safely transport to beam dumps• Optimize IR for all considered detector concepts• Minimize cost & ensure Conventional Facilities
constructability
Andrei Seryi ILC BDS, DOE review 5 June 2005
Choice of crossing angle has crucial influence on the machine performance, reliability, and affect physics reach• NLC @ 3ns bunch spacing => 20mrad x-ing; TESLA @ 300ns => chose head-on
• Incoming and outgoing beam are independent (+)
• Disrupted beam with large energy spread captured by alternating focusing, no need to bend the beam after collision => easier to minimize beam losses (+)
• Require compact SC quads and crab cavity
• The exit hole un-instrumented => loss of detector hermeticity (-)
• Low energy pairs spread by solenoid field => somewhat larger background
(-)
• No extra exit hole => somewhat better detector hermeticity (+)
• Low energy pairs spread less => somewhat better background (+)
• Require electrostatic separator with B-field or RF-kicker
• Incoming and outgoing magnets shared => difficult optics, collimation apertures set by outgoing beam (-)
• Need to bend disrupted beam with large energy spread => beam loss, especially at high energy, MPS (-)
Andrei Seryi ILC BDS, DOE review 6 June 2005
Evaluation of head-on design by TRC
• SLAC actively participated in ILC-TRC in 2002, including
• evaluation of BDS design and head-on scheme– Large losses in extraction line,
especially at 1 TeV– Incompatible with post-IP
E/Polarization diagnostics– Electrostatic separator
100kV/cm at 1TeV – feasibility in high SR environment
– MPS issues– losses at (or near) septum: ~5-15kW– Parasitic collision 26.5 m from IP @ 1TeV– SR masking over-constrained
Andrei Seryi ILC BDS, DOE review 7 June 2005
SLAC contributed to all aspects of turning the Strawman configuration into real design:
• Full optics for all beamlines; Well developed and optimized 20mrad optics and magnets design; The method and first iteration of optics and magnets for 2mrad IR; Upstream and downstream diagnostics for both IRs
1st ILC WorkshopNovember 2004
Andrei Seryi ILC BDS, DOE review 8 June 2005
to IR2
to IR1to dump
11 mrad Big Bend & polarimeter chicane
ILC2005 Beam Switchyard
• Optics Based on NLC design• Betatron collimation with
survivable spoilers• Energy & polarization
diagnostics
BDS for 20mrad IR
Andrei Seryi ILC BDS, DOE review 9 June 2005
20mrad IR, extraction & compact SC quads
• IR design based on compact SC quads developed at BNL
• Work closely with BNL on design of IR, SC quads, study of its stability
• Detailed model in Geant• Close connection with
detector groups optimizing IR and detector design
Andrei Seryi ILC BDS, DOE review 10 June 2005
2mrad IR: from concept to optics
• FF and extraction line optimized simultaneously
• Quads and sextupoles in the FD optimized to – cancel FF chromaticity– focus the extracted beam
SLAC-BNL-UK-France Task Group
QF1
pocket coil quad
O.Napoly, 1997
Andrei Seryi ILC BDS, DOE review 11 June 2005
2mrad IP Extraction Line in GeantSLAC-BNL-UK-France Task Group
QD0SD0 QF1
SF1QEXF1
BYCHICDisrupted beam & Sync radiations
Beamstrahlung
Incoming beam
60 m
Shared Large Aperture Magnets
Warm Panofsky septum quad(C.Spencer)
Rutherford cable SC quad and sextupole
No beam & losses for nominal parameters
pocket coil quad
Super Septum Quad, B.Parker et al.)
or
Andrei Seryi ILC BDS, DOE review 12 June 2005
Largest elements of BDS R&D with SLAC involvement
• Proposed End Station A at SLAC– Study Interaction Region issues and instrumentation– Mockup of full IR
• Existing ATF at KEK (DR and BDS related studies)– Instrumentation (Nano-BPM, laser wires, optical anchor)– Fast Intra-train feedback (FONT/Feather)– nm resolution BPM test & demonstration– Preparation of ‘ATF-2’
• Proposed ATF-2 at KEK – BDS facility, use very low emittance ATF beam
Andrei Seryi ILC BDS, DOE review 13 June 2005
End Station A Test FacilityEnd Station A Test FacilityFor Prototypes of Beam Delivery and IR ComponentsFor Prototypes of Beam Delivery and IR Components
CCLRC LLNL QMUL UCL U. of Bristol
CERN Lancaster U. SLAC UC Berkeley U. of Oregon
DESY Manchester U. UMass Amherst
U. of Cambridge
KEK Notre Dame U. U. of Birmingham
TEMF TU Darmstadt
http://www-project.slac.stanford.edu/ilc/testfac/ESA/esa.html
Collimator design, wakefields (T-480)BPM energy spectrometer (T-474)Synch Stripe energy spectrometer (T-475)IP BPMs, kickersEMI (electro-magnetic interference)IR Mockup
PAC05 paper/poster: SLAC-PUB-11180
e-Print Archive: physics/0505171
Andrei Seryi ILC BDS, DOE review 14 June 2005
End Station A for recent E158 experimentEnd Station A for recent E158 experiment
Experimental hall is 60 meters long
E158 completed in Sept. 2003 and allbeamline components in ESA have been removed.A concrete bunker (not shown) surrounds the beamline.
Andrei Seryi ILC BDS, DOE review 15 June 2005
ESA Test Facility: First ExperimentsESA Test Facility: First Experiments
T-480: Collimator WakefieldsCollimators remove beam halo, but excite wakefields.Goal is to determine optimal collimator material and geometry.
T-474, T-475: Energy SpectrometersPrecision energy measurements to 50-200 parts per million are needed for Higgs boson and top quark mass measurements. BPM and synchrotron stripe spectrometers will both be evaluated in a common 4-magnet chicane.
Andrei Seryi ILC BDS, DOE review 16 June 2005
Envision 2-week run in November 2005, and to have2-week runs ~every 6 months in 2006-2007.
E,z bunch distributions in ESA; 2E10 e-/bunch, 28.5 GeV
ILC bunch charge and bunch length
End Station A Test FacilityEnd Station A Test Facility
Andrei Seryi ILC BDS, DOE review 17 June 2005
Reasons to develop ATF-2 facility• Luminosity issues will be extremely
challenging in the LC– Likely more challenging than
achieving the beam energy• Complete FFTB studies
– FFTB never demonstrated routine operation of FFS
• Implement full feedback control and optimization
• Operate with ILC like bunch train and IP feedback
• Use stable low emittance beam from ATF DR
• Learn to operate new FF optics
• Experience concurrent with ILC construction– FFTB experience will be over 15
years old– Train new generation of physicists
ATF2 collaboration, presently 88 people from 21 labs and institutions and growing
KEK, TsukubaIHEP, Beijing
BINP, NovosibirskCCLRC/DL/ASTeC,Daresbury
CEA, Gif-sur-YvetteCERN, Geneva
Hiroshima UniversityKyoto ICR, Kyoto
LAL, OrsayLLNL, LivermoreNIRS, Chiba-shi
North Carolina A&T State UniversityOxford University
Pohang Accelerator LaboratoryQueen Mary University of London
Royal Holloway, University of LondonDESY, HamburgSLAC, Stanford
UCL, LondonUniversity of Oregon
University of TokyoATF2 proposal is to be released in June,
during the BDIR workshop in London
Andrei Seryi ILC BDS, DOE review 18 June 2005
Optics Design of ATF2
New Beamline
Beam
ATF2 design & goals(A) Small beam size
Obtain y ~ 35nmMaintain for long time
(B) Stabilization of beam center Down to < 2nm by nano-BPM Bunch-to-bunch feedback of
ILC-like train
New final focus
New diagnosti
cs
existing extraction
Andrei Seryi ILC BDS, DOE review 19 June 2005
Advanced beam instrumentation at ATF2• BSM to confirm 35nm beam size• nano-BPM at IP to see the nm stability• Laser-wire to tune the beam• Cavity BPMs to measure the orbit• Movers, active stabilization, alignment system• Intratrain feedback, Kickers to produce ILC-like
train
IP Beam-size monitor (BSM)(Tokyo U./KEK, SLAC, UK)
Laser-wire beam-size Monitor (UK group)
Cavity BPMs, for use with Q magnets with 100nm resolution (PAL, SLAC, KEK)
Cavity BPMs with 2nm resolution, for use at the IP (KEK)
Laser wire at ATF
Andrei Seryi ILC BDS, DOE review 20 June 2005
Summary
• ILC BDS design is making progress from the concept to optics, from optics to engineering design
• Strong R&D program is planned and ongoing
• SLAC actively contributing to all aspects of BDS design and R&D