Andrei Seryi ILC BDS, DOE review 1 June 2005 The ILC Beam Delivery System, ATF2 and ESA Andrei Seryi SLAC DOE High Energy Physics Program Review June 14-15,

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


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/


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


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


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 (-)


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


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


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


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


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


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


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


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


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.


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.


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


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


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


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


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

Documents

Andrei Seryi ILC BDS, DOE review 1 June 2005 The ILC Beam Delivery System, ATF2 and ESA Andrei Seryi SLAC DOE High Energy Physics Program Review June 14-15,