global design effort 1 summary of technical and collaboration related issues for the ilc damping...

Global Design Effort 1

Summary of Technical andCollaboration Related Issues for

the ILC Damping Rings

N. Walker(for the Project Managers)

INFN Frascati22 January 2009

22.01.2008 - INFN LNF

INFN and Damping Rings

• TESLA TDR– Full cost estimate of TESLA dogbone DR

(Ansaldo)

• EUROTeV (FP6) Programme– WP 3 Damping Rings

Coordination: S. Guiducci

• GDE ILC RDR– DR Area System European coordinator:

S. Guiducci (A. Wolski, J. Gao)

• Continued support & collaboration– DANE, SuperB,…

Global Design Effort

2001

2007

TDR 2012

22.01.2008 - INFN LNF 2

Technical Design Phase Project

• Three Project Managers– Yamamoto (SCRF)

– Ross (CFS/Global)

– Walker (AS)

• Accelerator Systems (AS) responsible for accelerator physics design– Damping Ring is one

Technical Area Group in AS

– (TAG leader: A. Wolski)

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Technical Design Phase Project

• DR TAG work-package structure reflects TD phase 1 focus on Beam Test Facilities

– CesrTA (e-cloud)– ATF (emittance, kickers,…)– DANE (e-cloud, kickers,…)

• Others: e.g. KEK-B

• Two additional WPs for ILC DR design work / costing– Lattice Design– Technical Systems

Global Design Effort22.01.2008 - INFN LNF 4

DR & BDS Beam Test Facilities

KEK, Japan

Cornell

INFN Frascati

CesrTA (Cornell)electron cloudlow emittance DANE (INFN Frascati)

kicker developmentelectron cloud

ATF & ATF2 (KEK)ultra-low emittanceFinal Focus optics

22.01.2008 - INFN LNF 5Global Design Effort

GDE ILC TD Phase R&D Plan

• Damping Ring: stated critical R&D:– Demonstration of electron cloud mitigation effects

(CesrTA programme, 2010)– Demonstration of ultra-low emittance (KEK ATF, 2009)– Development of 5 ns rise-time injection and extraction

kickers (DANE experiments, 2010)

• Damping Ring: Cost – performance studies– 2009: within “Minimum Machine” study– Specifically 3km ring option as part of “low-power”

option– Other “VALUE ENGINEERING” activities

• Vacuum system design

• Power supply solution / layout etc.

22.01.2008 - INFN LNF Global Design Effort 6

The ILC Damping Rings


• Energy 5 GeV• Number of bunches: 2625• Charge per bunch: 3.2 nC• Circumference: 6.695 km• tb 6 ns• Average current 0.4 A

• Emittances:

– Horizontal (equilibrium) 5 m– Vertical (extracted) 2 pm

• Damping time 25 ms

• Injection emittance (e+) 0.09 m (Ax+Ay)

The ILC Damping Rings

• Energy 5 GeV• Number of bunches: 2625• Charge per bunch: 3.2 nC• Circumference: 6.695 km• tb 6 ns fast kickers• Average current 0.4 A instabilities

(e-cloud)• Emittances:

– Horizontal (equilibrium) 5 m– Vertical (extracted) 2 pm beyond SotA

• Damping time 25 ms

• Injection emittance (e+) 0.09 m (Ax+Ay)


RDR Lattice (History)

6.7km

TME

22.01.2008 - INFN LNF 9Global Design Effort


Working Lattice (as of TILC08, March 08)

6.7 km ringz = 9mm 6mm (better for bunch compressor)

22.01.2008 - INFN LNF 10

Priority ILC DR R&D (risk mitigating)

• Electron Cloud– Characterise e-cloud build-up– Development of e-cloud suppression techniques– Develop modelling tools– …

• Demonstration of <2 pm vertical emittance– Development of low-emittance tuning techniques– Instrumentation– Alignment– …

• Fast injection / extraction kickers– Fast pulser technology <5ns rise time, 10-4 stability– Reliability / availability

• Other– Classical impedance-driven instabilities– Fast-ion instability– …

Global Design Effort22.01.2008 - INFN LNF 11

Priority ILC DR R&D (risk mitigating)

• Electron Cloud– Characterise e-cloud build-up– Development of e-cloud suppression techniques– Develop modelling tools– …

• Demonstration of <2 pm vertical emittance– Development of low-emittance tuning techniques– Instrumentation– Alignment– …

• Fast injection / extraction kickers– Fast pulser technology <5ns rise time, 10-4 stability– Reliability / availability

• Other– Classical impedance-driven instabilities– Fast-ion instability– …


TD Phase

priorityTD Phase

priority

TD Phase

priorityTD Phase

priority

TD Phase

priorityTD Phase

priority

22.01.2008 - INFN LNF 12

Program Outline


Minimum Machine

Technical Design, and Costing

Critical R&D

2008 Specify tasks. Specify scope.

Continue critical R&D for cost reduction and risk mitigation:

•electron cloud;

•fast kickers;

•low-emittance tuning.

2009 Perform studies.

Perform technical design and costing work in support of revising the baseline configuration.

Start 2010

Revise baseline configuration.

2010 – 2012

Complete work for TDR (end 2012).

Complete critical R&D.

TDPPhase I

TDPPhase II

Electron Cloud: Goals

1. Collect data to validate the simulation codes in the parameter regime of the ILC damping rings.

– We need to understand, and be able to predict, build-up of the cloud under a variety of conditions.

– We need to understand, and be able to predict, beam dynamics with e-cloud in ultra-low emittance regime.

2. Develop effective mitigation techniques.

– Mitigation methods needed for drifts, dipoles, wigglers.

– Methods must be demonstrated and adverse consequences understood.


Critical R&D: Electron Cloud


CesrTA

KEKB

DANE

E-Cloud Collaboration:•ANL•Cornell•FNAL•INFN/LNF•KEK•LBNL•SLAC

E-Cloud Studies at DANEMultibunch instability caused by electron cloud.

Simulations consistent with main observations.


60 equispaced bunches

Beam current 1.2 A

Growth time ~ 100 turn

Fast Kicker R&D

• The goal is to develop and demonstrate a high-reliability fast kicker that meets the ILC specifications for damping ring injection and extraction.

• R&D program includes activities at SLAC, INFN/LNF and KEK.


Pulse amplitude 10 kV

Bunch spacing 3 ns

Pulse repetition rate 6.6 MHz

Pulse stability ~ 0.1%

Fast Injection/Extraction Kickers: LNF

Fast, high-power pulsers approaching ILC DR specifications are being tested as part of DANE upgrade program.


45 kV 5 ns pulse (FID)

DANE stripline kicker designs are being modified for devices to be installed for testing in ATF.

Low-Emittance Tuning

• ILC damping rings are specified to operate with 2 pm vertical emittance.

• Swiss Light Source has recently achieved 3 pm.

• Low-emittance tuning program includes work at:– ATF: studies of fast ion instability, and demonstration

for ILC damping rings (also critical for ATF-2);

– CesrTA: motivated by studies of electron cloud in ultra-low emittance regime;

– Cockcroft Institute: in support of ATF and CesrTA programs, and ILC damping rings design.

• Issues include: alignment and stabilisation specifications; diagnostics and instrumentation functionality and performance; design of coupling correction system; development of effective tuning techniques...


Damping Rings Design and Costing (1)

Significant progress is being made with a CAD model for the present baseline lattice.


Gate Valves

Electron Vessel

Positron Vessel

Straight Cylindrical VesselTapered Vessel

Ante-Chambered Vessel

Tapered VesselPumping Port

BPM Station(Electron)

BPM Station(Positron)

Gate Valves

Development of the CAD model provides essential information for:•technical systems development (vacuum, conventional facilities...);

•costing and value engineering;

•beam dynamics studies (low emittance tuning, e-cloud...)


Damping Rings Design and Costing (2)

Vessel with antechamberfor e-cloud mitigation.

BPM chamber with position encoders.

BPM/bellows willcontribute to machine impedance.

“Minimum Machine” Studies


Nom. RDR Low P RDR new Low P ECM (GeV) 500 500 500 Particles per bunch, N (×1010) 2.0 2.0 2.0Bunches per pulse, nb 2625 1320 1320 Pulse repetition rate (Hz) 5 5 5 Peak beam power, Pb (MW) 10.5 5.3 5.3 x (m) 10 10 10y (nm) 40 36 36x (cm) 2.0 1.1 1.1y (mm) 0.4 0.2 0.2Traveling focus No No Yes x (nm) 640 474 474y (nm) 5.7 3.8 3.8 z (m) 300 200 300 Beamstrahlung* E/E 0.023 0.045 0.036 Luminosity* (×1034 cm-2s-1) 2.0 1.7 1.9


• Main implication for the damping rings is that the “low power” parameter set makes a 3 km circumference feasible.– Number of bunches in the ring is halved.– Average current and bunch separation remain constant.

• Reducing the circumference makes it possible to contemplate also reducing the beam energy.– Maybe reduce from 5 GeV to 4.6 GeV, or 4.2 GeV. Reduces longitudinal emittance, with benefits for the

bunch compressors. Reduces amount of wiggler, rf, magnet power, etc. Injected beam sizes becomes larger. Beam becomes less robust against collective effects.



• We have two lattices that can be used as a basis for 3 km damping ring studies...

• ...one of them produced by replacing the arc cells in the present baseline lattice, with cells based on those used in SuperB.


-600 -400 -200 0 200 400 600 800-500

-400

-300

-200

-100

0

ILC Damping Ring

Plans for TDP-I/Minimum Machine


Task Responsibility

Modify/develop 3 km damping ring lattice design. Korostelev/Biagini

Evaluate dynamics in 3 km damping ring. Korostelev/Biagini

Develop lattice designs for injection/extraction lines. Guiducci

Continue to develop impedance model. Korostelev/Marcellini

Develop and maintain CAD models. Lucas

Update and maintain cost estimates. Lucas

Specify and cost power distribution system. Palmer/Bellomo

1. Continue critical R&D:

• electron cloud; fast kickers; low emittance tuning.

2. Produce technical evaluation and cost comparison of 6 km and 3 km damping ring options, by end 2009, to support possible new baseline.

3. Continue technical design and costing work for TDR.

ILC-CLIC Collaboraton

• Differences in linac technologies drive damping rings to different configurations in ILC and CLIC, however...

• ...there are a number of high-priority issues that are common for both projects:

– electron cloud mitigation;– ultra-low emittance tuning and

preservation.• A first step toward closer collaboration

has already been taken, in coordinating CLIC and ILC damping rings WebEx meetings.

• A joint working group on damping rings is now being established, convened by Yannis Papaphilippou and Mark Palmer.

22.01.2008 - INFN LNF Global Design Effort

ILC CLIC

Energy (GeV) 5 2.4

Circumference (m) 6476 365

Bunch number 2700-5400 312

Particles/bunch (1010) 2.0-1.0 0.37

Damping time x (ms) 21 1.5

Emittance x (nm) 4200 381

Emittance y (nm) 20 4.1

Momentum compaction (10-4) 1.3-2.8 0.80

Energy loss/turn (MeV) 8.7 3.9

Energy spread 1.3x10-3 1.4x10-3

Bunch length (mm) 9.0 - 6.0 1.53

RF Voltage (MV) 17 - 32 4.1

RF frequency (MHz) 650 2000

26

Summary• Post RDR, GDE has shifted into a more formal

project structure• Technical Design Phase 1 (to 2010) focused on “Risk

Mitigating” R&D– Electron Cloud– Fast kicker development– 2pm emittance

• DR design work focus on cost / performance optimisation– Including 3km ring option

• INFN LNF has a long history of involvement/collaboration in ILC DR design work– We hope to build on this solid base in the future

Global Design Effort 2722.01.2008 - INFN LNF

global design effort 1 summary of technical and collaboration related issues for the ilc damping...

Documents

infn lnf slide

global design effort

infn lnf global design

wolski global design

y slide

da ne ecloud

project managers infn

cloud suppression techniques