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