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Staging and Energy upgrade scenarios. K.Kubo. Staging?. If we want to start operation with half cavities, how to distribute them?. A. ML. BDS. No cavities. Full. B. ML. BDS. Sparse cavities (e.g. every other place). A will be better from beam dynamics, preserving low emittance beam. - PowerPoint PPT Presentation
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Staging?
BDS
ML
BDS
ML
No cavitiesFull
Sparse cavities (e.g. every other place)
A
B
A will be better from beam dynamics, preserving low emittance beam.But, how important?
If we want to start operation with half cavities, how to distribute them?
Simulation for Final Ebeam 125 GeV
BDS
ML
BDS
ML
No cavitiesFull
Sparse cavities (every other place)
A
B
No cavities
15 GeV 125 GeV
BDS
ML
Low gradient (all cavities installed)
C (for comparison)
No cavities
Same Optics
Vertical emittance along the linac, mean of 100 random seeds.“Standard errors” (except Q roll) and Dispersion Matching Steering
125 GeV C
2 10-8
2.1 10-8
2.2 10-8
2.3 10-8
2.4 10-8
2.5 10-8
2.6 10-8
2.7 10-8
0 2000 4000 6000 8000 1 104
mean of 100 seeds
125 GeV Low Gradient125 GeV Cav. 1st part125 GeV Sparse Cav. 250 GeV
mea
n y (
m)
s (m)
125 GeV A
125 GeV B
250 GeV
No significant difference between A (fill cavities in 1st part) and B (sparsely distributed cavities)
Error RTML and ML Cold with respect to
Quad Offset 300 μm cryo-module
Quad roll 300 μrad design
RF Cavity Offset 300 μm cryo-module
RF Cavity tilt 300 μrad cryo-module
BPM Offset (initial) 300 μm cryo-module
BPM Resolution 1 μm ---
Cryomoduloe Offset
200 μm design
Cryomodule Pitch 20 μrad design
“Standard” Error in ML
2 10-8
2.01 10-8
2.02 10-8
2.03 10-8
2.04 10-8
2.05 10-8
2.06 10-8
2.07 10-8
0 2000 4000 6000 8000 1 104
Ebem
=125 GeV, low gradient (C)
Ebeam
=125 GeV, sparse cavities (B)
Ebeam
=125 GeV, cavities in first part (A)
Ebeam
=250 GeV
Mea
n
-cor
rect
ed y
(m
)
s (m)
Vertical emittance along the linac, mean of 100 random seeds.“Standard errors” (except Q roll) and Dispersion Matching SteeringZero bunch charge (no wakefield)
125 GeV C
125 GeV A
125 GeV B
250 GeV
Most emittance growth is from wakefield.Further correction for wakefield (wake bump) can reduce emittance close to this figure.
Comparison of different choices for 125 GeV and 175 GeV250 GeV for comparisonWith and without wakefield
0
0.1
0.2
0.3
0.4
0.5
125 GeV
sparce cav
175 GeV
sparce cav.
125 GeV
Cav in 1st part
175 GeV
Cav in
1st part
125GeV
low grad.
175 GeV
low grad
250 GeV
N=2E10
N=0M
ean
y/
y0
Mean (dot) and Standard dev. (bar) of 100 seeds
No significant difference between A (fill cavities in 1st part) and B (sparsely distributed cavities)
Energy upgrade (ECM 500 -> 1000 GeV)
• Review of old story.
• FODO or FOFODODO lattice?
• 3 or 4 modules/quad?
BC (5-15 GeV)ML (15-25 GeV)Special mag. ML (25-250 GeV)
New part (25-275GeV)
Move to upstream Keep for275 – 500 GeV
Upgrade Ebeam from 250 to 500 GeV
3 modules/quad FODO
Strengths of quads in E_beam > 250 = Strength at 250 GeV Or, K1 ~ 1/E_beam
3 modules/quad FOFODODO
Strengths of quads at E_beam = 500 = Strength at 250 GeV K1(E_beam > 250 GeV) = ½ K1(E_beam < 250GeV)
Weak magnets for Ebeam 275 – 500 GeV
FOFODODO can make dispersion in downstream part small.Loose tolerance of BPM scale error in DMS correction.
Simulation results of DFS with “standard” static errors
2 10-8
2.2 10-8
2.4 10-8
2.6 10-8
2.8 10-8
3 10-8
0 5000 1 104 1.5 104 2 104
FDFD BPM scale error 0FDD BPM scale error 0
<
y,
-cor
rect
ed>
(m
)
s (m) average of 40 seeds
Simulation results of DFS with “standard” static errors + BPM Scale error 5%
average of 40 seeds
2 10-8
2.5 10-8
3 10-8
3.5 10-8
4 10-8
4.5 10-8
5 10-8
0 5000 1 104 1.5 104 2 104
FDFD, BPM scale error 5%
FFDD BPM scale error 5%
<
y,
-cor
rect
ed>
(m
)
s (m)