Status and Plan of GDE Design Work (Including Road Map for RDR)

Feb. 17 2006

PAL

Eun-San Kim

ILC Meetings

Snowmass, Colorado, 14-17 Aug. 2005 : Started BCD European GDE meeting, Oxford, 25 Oct. 2005 Damping ring workshop, CERN, 9-11 Nov. 2005 GDE meeting, Frascati, Italy 7-9 Dec. 2005 : Decided BCD 1st Area System meeting, KEK, 19-20 Jan. 2006 : Discussed machine layout and boundary between area systems Lattice design meeting, CERN, 6-8 Feb. 2006 2nd Area System meeting, FNAL, 13-14 Feb. 2006 GDE meeting, Bangalore, 9-11 March 2006 3rd Area system meeting, DESY, April 2006 GDE meeting, Vancouver, 19-23 July 2006 GDE meeting, Valencia, Autumn 2006

Frascati GDE Meeting

Discussed progress since Snowmass

Finally agreed BCD to be documented. - includes baseline and alternative designs

Organized the GDE group for RDR in 2006

Final BCD becomes property of CCB in early 2006

Frascati GDE Meeting BCD layout

Working Group for BCD

WG1 : LET beam dynamics WG2 : Main Linac

WG3a : Sources WG3b : Damping Rings

WG4 : Beam Delivery WG5 : SCRF Cavity

IP

Matrix group for RDR

A. BrachmannM. KurikiJ. Sheppard

J. GaoS. GuiducciA. Wolski

E.-S. KimP. Tenenbaum

C. AdolphsenH. HayanoL. LiljeN. Solyak

D. A-KA. SeryiH. Yamamoto

Area system is geographical breakdown of

machine for design and cost estimation

Frascati GDE Meeting

1st Area system meetingBaseline Layout (500 GeV)

- 1st stage : 500 GeV

- 2nd stage : 1 TeV ; Moving of turn-around and BC

No moving of DR

laser NC pre-accelerator

400 MeV SC Linac Eacc = 17.8 MV/m

diagnostic sectionNC SHB+solenoid

70-100 MeV12 MeV120 keV DC Gun

Electron source in BCD

Positron source in BCD

150 GeV e-

Undulator ~100m

To DR

To IP

e-

Ti Alloy

Target

e+

Accelerating structure

Damping Ring in BCD

Baseline

e+ : two 6 km rings

e- : one 6 km ring

Alternative

e+ : 6 km, 17 km

Baseline

DR Tasks List for RDR

Lattice design

- 6 km e-/e+ rings : L. Emery, A. Xiao, E-S Kim, Y. Sun

- 17 km e-/e+ rings : Y. Cai, Y. Yan

- Injection and extraction lines : A. Wolski

Acceptance : Y. Cai, Y. Yan, A.Wolski

Low-emittance tuning : J. Jones

Impedance : M. Venturini, K. Bane, S. Heifets, etc Electron-cloud : M. Pivi, C. Celata, K. Ohmi etc.

Ion-effects : L. Wang, E-S Kim, K. Ohmi, M. Venturini, G. Xia

Other collective effects : S. Mtingwa, M. Venturini, S. Santis, A. Wolski

Injection/extraction kickers : pulser

: J. Urakawa, T. Naito, M. Ross, A. Krasnykh, etc

Injection/extraction kickers : striplines

: A. Krasnykh, S. Santis, D. Alesini, F. Marcellini

DR Tasks List for RDR

Baseline Damping Ring

Circumference 6.6 km

Energy 5 GeV RF frequency 650 MHz Harmonic number 14402 Damping time < 25 ms (e+) < 50 ms (e-) Emittance 5 m Bunch length 6 mm Energy spread < 0.13 %

Momentum compaction 4x10-4

Damping wiggler peak field 1.6 T Damping wiggler period 0.4 m Energy acceptance < 0.5 %

Dynamic aperture Ax+Ay < 0.09 m-rad

Baseline Damping Ring

Bunch filling patterns for e-

650 MHz, 5400 bunch

Fast-ion effects in Baseline Damping Ring

Sq

rt(J

y)

Beam size

per 50 turns

One straight section

A lattice with low average beta-functions to reduce the effects of fast-ion.

Tele-conference for e- DR lattice will be at the beginning of March.

Lattice Design of Electron damping ring

One Arc and Wiggler section

Started works for shorter bunch compressor and turn-around optics

Contacted leaders of all technical and global systems

Milestone

- Review RTML design and place lattices and documentation under change control in April 2006

Ring to Main Linac (RTML) Status and Plans

-1800 -1600 -1400 -1200 -1000 -800 -600 -400 -200 0 200-10

0

10

20

30

40

50

60

Z position [m]

X P

ositio

n [

m]

Anamorphic Diagram of RTML Footprint

Skew CorrectionCollimation

DR Stretch

Turnaround

Spin RotatorEmittance

BC1

BC2Linac Launch

Total 2.5 km

Turn around

ny = 0.02 m, 3.2 nC, z = 6mm

BC 2BC 1SR z = 0.15 mm

Ring to Main Linac (RTML)

RTML Layout

Alternative Baseline

Required bunch length

achieved achieved

System length shorter longer

Tolerence of emittance

acceptable

comparable

acceptable

comparable

BCD alternative baseline

GDE

Requirement

correction of vertical dispersion

shorten

system length

Alternative Baseline

Chicane 68.4 m 480 m

Matching 4 m 310 m

Number of RF cavity 452 488

Total length 680 m 1400 m

Ring to Main Linac (RTML)

Bunch compressor

Each BC in baseline has 240 meters of bend magnets arranged in chicanes : Long !

Considering two approaches to reduce length– Enhancing R56 by forcing nonzero dispersion at Qs

– Replacing wiggler with 4-bend chicane with optimized lattice functions for emittance preservation

Ring to Main Linac (RTML)

Bunch compressor

Main Linac in BCD

Baseline in 1st stage - TESLA cavity type

- Operation gradient = 31.5 MV/m, Qo=1010

Baseline in 2nd stage - LL or RE cavity type

- Operation gradient = 36 MV/m, Qo=1010

- Total length = 41 km

Alternative in 1st stage - LL or RE cavity type

- Operation gradient = 36 MV/m

Linac RF basic unit - 1 modulator, 1 klystron, 3 cryomodules, 27 cavities

Beam Delivery System in BCD Baseline :

- 2 IPs for 2 mrad and 20 mard

- 150 m longitudinal separation between 2 IPs

Alternative :

- 1 IP

Bangalore GDE meeting

- starting for estimation of costs

RDR will be finished in Dec. 2006

- RDR is not complete technical design,

but is a design to estimate reliable cost.

TDR will be completed in Dec. 2008.

Summary