Center for Beam Physics

John CorlettAccelerator and Fusion Research Division

Lawrence Berkeley National Laboratory

Presented to the AARD Sub-panel meeting

Palo Alto, California

December 21, 2005

CBP accelerator R&D activities

• CBP provides integrated resources to address accelerator science and technology questions and to extend the limits of performance of accelerators

– Accelerator science– Advanced computing and accelerator modeling– Beam electrodynamics– LBEL experimental laboratory (RF, microwave, lasers)

– An incubator for new concepts and future initiatives

– A history of significant involvement in successful accelerator construction projects (e.g. ALS, PEP-II)

– A foundation for support of existing projects and initiatives (e.g. PEP-II, Tevatron, LHC, LARP, ILC)

• Capable and responsive to HEP needs

Center for Beam Physics

J. Corlett

ES&HCoordinator

S. Lidia

Initiatives/Projects

ILC

A. Wolski

Future Light Sources

J. Corlett

Beam Theory

M. Furman

Accl. Modeling & Adv. Computing

R. Ryne

BusinessManagerG. Rogers

Groups

Beam Electro-dynamics

J. Byrd

Collider Physics

M. Zisman

Organization / management

Accelerator & Fusion Research Division

CBP staff

~50 headcount~25 FTE

CBP FY06 anticipated funding

Early SSC beam dynamics• Original ALS concept and designTwo-beam accelerator development and design• Concept of beam conditioningFirst study and design of the asymmetric e+e– colliderInitial PEP-II positron ring designBroad-band, high-gain, multi-bunch feedback systems“Monochromatic” damped RF cavity designConcept of optical stochastic cooling and proposed tests at RHIC• Forefront FEL theoretical and numerical research• Concepts for optical manipulation of electron beamsDesign and evaluation of NLC - now ILC - damping ringsEarly original contributions to collider, -collider and -factory

designsEssential beam dynamics concepts (Lie map techniques, symplectic

integration, beam-beam and e-cloud dynamics, …)

Center for Beam Physics has long history of driving tools for accelerator science

= HEP AARD activity

Beam impedance calculation and measurementCollective effects analysis Electron cloud modeling and benchmarking of codes• Concept and design of LUX ultrafast light source• Concept of ultra-bright electron sourceOptimized RF structures for ionization cooling schemes• Ultra-stable optical timing and synchronization systems• High-brightness, high-power RF gun designDipole mode “crab” cavity designOptical diagnostics for high-energy hadron machinesCoherent synchrotron radiation (CSR) diagnosticsAdvanced computing and highly-parallelized modeling codesEssential development of algorithms for modeling long-range beam-beam &

cathode image effectsSupport for Tevatron and PEP-II luminosity improvements

Center for Beam Physics has long history of driving tools for accelerator science

= HEP AARD activity

PEP-II damped cavities - essential technology for high intensity storage rings

• R&D in monochromatic RF structures

• Waveguide damping reduces HOM impedance by up to 1000x

Ionization cooling RF R&D - developing concepts for future facilities

• “Pillbox” cavities with high shunt impedance

• Thin Be foil (or grid) structures over large aperture

• Successful tests up to 40 MV/m achieved (805 MHz)

dxdE

dxdE

dxdE

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are needed to see this picture.

Hardware for MICE experiment

• LBNL responsibilities• Design and fabrication of

prototype cavity• Design of superconducting

“coupling coil” solenoid• Cooling channel integration

Prototype 201 MHz cavity

Ongoing RF structure R&D - “crab” cavities for colliders, applications in LHC, ILC, Super B-factory

Concept - unwanted modes are heavily damped in

waveguide

• Highly damped dipole mode superconducting cavities

• Maintain cylindrical symmetry for ease of production

D BC A

pick-up 1

pick-up 2

poweramplifiers

horizontal kicker vertical kicker

verticalprocessing

beam

V2 V1

H2

V2

receiver2

C2

variableattenuators

C1

PEP-IITRANSVERSE COUPLED BUNCH FEEDBACK

Σ

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BPF1.5 GHz LPF

horizontalposition

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verticalposition

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receiver1

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delay

DAC

ADC

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Multi-bunch feedback systems - essential technology for control of high intensity beams e.g. ILC damping rings

• Bunch-by-bunch feedback systems control coupled-bunch instabilities

• Highly successful implementation in PEP-II and ALS

• Upgrades for PEP-II implemented • FPGA technology• Instability studies initiated

Feedback kickers installed at PEP-II

Expertise in instrumentation led to LARP support - LHC Luminosity Monitor

The challenge:• High radiation environment (100 MGy/year)• Real-time diagnostic with bunch-by-bunch capability (25 nsec

separation) with 1% resolution

The solution:• Segmented, multi-gap, pressurized ArN2 gas ionization chamber

constructed of rad hard materials

• Prototype built & tested at ALS

• Moving into production

9 cm

Expertise in instrumentation led to LARP support - LHC Luminosity Monitor

The solution:• Segmented, multi-gap, pressurized ArN2

gas ionization chamber constructed of rad hard materials

• Prototype built & tested at ALS

9 cm-20mV

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-5

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Signal (mV)

680ns660640620600580

Time (nsec)

Measured pulse response

22 nsec

Application of expertise in optical diagnostics for proton machines - Tevatron, LHC

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Time (2ns)

Bunch 1 Bunch 36

End of Abort Gap 3

bins (2 ns)

Microbunches are clearly visible. Diffusion process under study.

Gated MCP-PMT

• At TeV energy scales, proton machines start to look more like electron synhcrotrons• Use synchrotron radiation optical diagnostics• Abort gap monitor

- Tested at Tevatron- Explored potential use at LHC

Application of expertise in optical diagnostics for proton machines - Tevatron, LHC

0 50 100 150 200 250 300 350 4000

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Time (2ns)

Bunch 1 Bunch 36

End of Abort Gap 3

bins (2 ns)

Microbunches are clearly visible. Diffusion process under study.

Gated MCP-PMT

• At TeV energy scales, proton machines start to look more like electron synhcrotrons• Use synchrotron radiation optical diagnostics• Abort gap monitor

- Tested at Tevatron- Explored potential use at LHC

• AP2 transfer line

– Large beamsize and energy spread

– Only ~1% is antiprotons

• Chromatic & large amplitude effects

– Mismatch between transfer line and debuncher

• Developed lattice to improve proton transmission into debuncher

– sextupoles

– matching

Core expertise enabled LBNL to respond to Tevatron luminosity improvement studies - antiproton beam dynamics

x, y phase space at end of AP2

Optical stochastic cooling - potential for technology for proton cooling

Amplified signal

s

p

Pump laser

i = p - s; kp = ks + ki

Beam

s

p

RHIC parameters: 1hr horizontal and longitudinal cooling time for gold beam requires 16 W of power = 12 µmBandwidth ~ 3 THz

LDRD test at BNL ATF for Optical Parametric Amplification

Optical amplifier is based on 3.5 cm CdGeAs2 crystal with d14=236 pV/m

Freshly grown crystals at Lockheed Sanders, NHDevelopments at RHIC, e- cooling proposal at MIT-Bates

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Coupled bunch mode number

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NLC damping rings - LBNL responsibility for critical system for linear colliders

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• Lattice design• Beam dynamics• RF• Impedance• Collective effects • …

ILC damping rings and bunch compressors - baseline configuration intensively developed by LBNL

• Damping rings: lattices and beam dynamics– Continued optimization of lattice designs

– Detailed studies of acceptance limitations (e.g. from wiggler)

– Detailed studies of collective effects (including space-charge, and coupled-bunch instabilities)

– Continued development of software tools for beam dynamics studies in DRs

• Damping rings: technical components and subsystems– Continued investigation of low SEY preparations for preventing electron

cloud

– Development of fast stripline kicker for ATF2 extraction

– Specification of vacuum system components to achieve 0.1 ntorr

– Cost estimates of different DR options, to inform selection of design for CDR

• Bunch compressors– Continued development of multi-stage designs

– Detailed performance evaluation of different BC options

Pioneered the field of Electron Cloud Effect (ECE) simulations and analysis - critical capability

• Initially developed for PEP-II, now applied to many other machines• Code POSINST developed at LBNL and SLAC and tested at APS and

PSR• Continue to be leaders in ECE studies

– the ECE is a possible performance-limiting issue

• Important potential constraint in many machines– Critical work continues

• Relevant to present and future machines (e.g. LHC, ILC, Proton Driver)

– Simulations for LHC and SPS– Evaluate ECE power deposition at LHC– Close contact with CERN

Electron cloud simulations - WARP/POSINT self-consistent 3-D simulation tool

Adaptive Mesh Refinement x20,000 speedup

beam (scaled 10x)

electrons

1 LHC FODO cell

F B B B D B B B

T=2s Actual LHC pipe shape/dimensions

beam

Ongoing R&D - electron cloud simulations comparison with experiment, collaboration with HIF-VNL group at LBNL

The magnetic section is heavily instrumented for electron effect studies

INJECTOR MATCHINGSECTION

ELECTROSTATICQUADRUPOLES

MAGNETICQUADRUPOLES

Focus of CurrentGas/Electron Experiments

MA4

BPM (3)

FLS(2)

GIC (2)

Current HCX Configuration

Integrated program with theory, simulation, and experimental facility - address physics issues critical to HEP

Suite of codes includes new advanced algorithms:New electron mover

• x10-100 speedup

Adaptive Mesh Refinement • x20,000 speedup on LHC run!

Being benchmarked against HCX expt. data

WARP-3DT = 4.65s

OscillationsElectrons bunching

Beam ions hit end plate

- implemented - in development

experimentsimulation

(a) (b) (c)

e-

+9kV +9kV +9kV 0V

MA4MA3MA2MA1

200mA K+

(a) (b) (c)

“Roadmap” for self-consistent modeling

200mA K+

AMAC activities support HEP priorities

• Modeling beam-beam effects in Tevatron

• Modeling strong-strong beam-beam effects in LHC

• Collaboration to model FNAL booster

• NLC damping ring design using MaryLie to simulate beam dynamics in wiggler magnets

• ILC damping ring design using MaryLie/Impact to study space charge effects

• Simulations in support of l’OASIS experiments

SciDAC presentation

by Rob Ryne

CBP AARD activities - summary

AARD activities in CBP meet critical needs of HEP

– CBP provides an incubator for major developments and new concepts

– Multi-disciplinary expertise • Accelerator physics and theory• Advanced computing for accelerator modeling• Beam electrodynamics

– Resources• LBEL experimental laboratory

HEP accelerator R&D funding is core to maintaining expertise

A broad R&D program provides HEP with high-value development of science and technologies for application in short (30%), medium (50%),

and long-range (20%) plans

– Expertise developed in medium and long-range R&D allows CBP to respond to short-term needs

– Foundation for support of existing projects and for future initiatives critical to HEP