Hybrid Synchrotron Arc: 2 Dipoles per Half Cell, Warm at F J. Scott Berg Advanced Accelerator Group...
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Hybrid Synchrotron Arc: 2 Dipoles per Half Cell, Warm at F J. Scott Berg Advanced Accelerator Group Meeting 3 August 2011
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Transcript of Hybrid Synchrotron Arc: 2 Dipoles per Half Cell, Warm at F J. Scott Berg Advanced Accelerator Group...
Hybrid Synchrotron Arc:2 Dipoles per Half Cell, Warm at F
J. Scott BergAdvanced Accelerator Group Meeting
3 August 2011
J. S. Berg: Hybrid, Warm near F 2
Basic Arc Cell: Dipole Arrangement
Cold DWarm Warm Cold
3 August 2011
Cold DWarm WarmCold
J. S. Berg: Hybrid, Warm near F 3
Optimization Process
• Find closed orbit at 375 GeV with warm dipoles at −1.8 T, 750 GeV with warm dioples at +1.8 T
• Set tunes to desired values, times of flight equal using quad fields and warm dipole length
• Minimize excursion with cold dipole length• Adjust quadrupole lengths so pole tip fields low
enough
3 August 2011
J. S. Berg: Hybrid, Warm near F 4
Results and Analysis
• Warm near F overall better than warm near D– Larger excursion for given number of cells, but– Lower circumference for given number of cells– Lower excursion for given circumference
• Warm near F: F is combined-function bend– D acts in wrong direction with warm near D
3 August 2011
J. S. Berg: Hybrid, Warm near F 5
Comparison: Warm near D or F
3 August 2011
5.6
5.8
6.0
6.2
6.4
6.6
6.8
7.0
4 6 8 10 12 14 16
Cir
cum
fere
nce
(km
)
Cells per Superperiod
Warm near FWarm near D
10
15
20
25
30
35
40
4 6 8 10 12 14 16
Ho
rizo
nta
l Dis
pla
cem
en
t (c
m)
Cells per Superperiod
Warm near FWarm near D
J. S. Berg: Hybrid, Warm near F 6
Results and Analysis
• Tune range for optimal circumference different for low and high number of cells– Low number of cells: lowest tune, both planes– Higher number of cells: second lowest tune
horizontal, lowest vertical– Low tune: less quad length to get focusing
• Higher tunes help keep excursion down
• Similar behavior for warm near D, but doesn’t appear in our range
3 August 2011
J. S. Berg: Hybrid, Warm near F 7
Results and Analysis
• Optimal tunes: low vertical helps everything• Displacement likes horizontal tune near 0.25• Circumference likes horizontal tune just below
0.25• Probably prefer horizontal tune just below
0.25: small penalty to displacement
3 August 2011
J. S. Berg: Hybrid, Warm near F 8
Warm Near F: Tune Dependence
3 August 2011
0.0
0.1
0.2
0.3
0.4
0.5
0.0 0.1 0.2 0.3 0.4 0.5
Ve
rtic
al C
ell
Tu
ne
Horizontal Cell Tune
5.8
6.0
6.2
6.4
6.6
6.8
7.0
Cir
cum
fere
nce
(km
)
0.0
0.1
0.2
0.3
0.4
0.5
0.0 0.1 0.2 0.3 0.4 0.5
Ve
rtic
al C
ell
Tu
ne
Horizontal Cell Tune
20.0
20.5
21.0
21.5
22.0
22.5
23.0
23.5
24.0
Ho
rizo
nta
l Dis
pla
cem
en
t (c
m)
J. S. Berg: Hybrid, Warm near F 9
Conclusions, Next Steps
• 2 dipoles per cell, warm near F best arrangement
• Displacements still high, but haven’t found minimum
• Next step is to try three dipoles per cell, looking at two possible arrangements– Expect warm in center reduces excursion in
quadrupoles
3 August 2011
J. S. Berg: Hybrid, Warm near F 10
Arrangement of Dipoles
C DWarm Warm
Cold DW Cold
vs.
C C C
WWW
3 August 2011
