Filling Schemes proposed for the 2010 Heavy Ion Run
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Transcript of Filling Schemes proposed for the 2010 Heavy Ion Run
Filling Schemes proposed
for the 2010 Heavy Ion Run Content
Introduction A scheme with 140 bunches/ring (minimum spacing 500 ns)
Filling scheme and pattern Collision pattern (scheduling)
A scheme with 124 bunches/ring (minimum spacing 600 ns) Filling scheme and pattern Collision pattern (scheduling)
Summary and Conclusions
Alternative filling schemes to increase Luminosity … adaptations of EARLY scheme Increase of (minimum) filling time to ~7 mins/ring
Further steps (if decision to in increase the number of LHC ion bunches in 2010): Which scheme to be used … may-be further variant to be studied? Discuss with relevant SPS and LHC (RF, BI, machine protection …?) experts
LHC-BCWG, 28th September 2010 Filling Schemes proposed for the 2010 Ion Run C.Carli and J.Jowett 1/6
Introduction
• EARLY scheme adopted in 2003 for the first ion run(s):– Luminosity 5×1025 cm-2 s-1 (instead of NOMINAL 1027 cm-2 s-1)
• Running conditions (b*=3.5 m instead of 1.0 m and half the design energy):– Further drop of the luminosity to ~0.7×1025 cm-2 s-1
• Compensate partly by increasing (roughly doubling for the schemes presented here) the number of bunches
• “Only” adaptation of the EARLY scheme– No variants of the NOMINAL scheme proposed … keep it simple
– Transparent for Linac3, LEIR and PS (one LHC ion bunch per cycle)
– SPS accumulates four PS transfers … keep SPS magnetic cycle
– Decrease distance between bunches in SPS (some change for RF, timings) to create space
– Increase number of SPS cycles to fill one LHC ring …. and, thus, the LHC filling time to a minimum of ~7 min/ring
– All three experiments (ALICE, CMS and ATLAS) taking ion data request non-colliding bunches
LHC-BCWG, 28th September 2010 Filling Schemes proposed for the 2010 Ion Run C.Carli and J.Jowett 2/6
A scheme with 140 bunches/ring Filling scheme and pattern
Very regular filling pattern (is this a real advantage?):• Basic building block - SPS accumulates 4 bunches (1 per transfer from PS) spaced by 500 ns - 975 ns for LHC injection kicker - total duration: 2475 ns or 99 “25ns positions” • 35 times this basic building block (36 times would fill an LHC ring 36*99 = 3564)• longer gap for the dump kicker
LHC-BCWG, 28th September 2010 Filling Schemes proposed for the 2010 Ion Run C.Carli and J.Jowett 3/6
A scheme with 140 bunches/ring Collision pattern (scheduling)
• First bunches of trains must NOT encounter at one of the IPs (to have non colliding bunches)
• Collision patterns, if first bunches encounter (just an example) at point 7
– Black: collisions– Red and Blue: bunches in ring 1 and 2
not colliding with bunch in other ring
First bunch(both rings)
Abort gapring 1
Abort gapring 2
LHC-BCWG, 28th September 2010 Filling Schemes proposed for the 2010 Ion Run C.Carli and J.Jowett 4/6
A scheme with 124 bunches/ring Filling scheme and pattern
• Basic building block:– Four bunches spaced by 600 ns– LHC injection kicker 975 ns– Total duration: 2775 ns or 111x25 ns
• Filling of one regular quarter:– Eight of above blocks plus 75 ns (increase spacing to
1050 ns• Abort gap: for one quarter leave one building block
1050 ns + 2775 ns = 3825 ns
LHC-BCWG, 28th September 2010 Filling Schemes proposed for the 2010 Ion Run C.Carli and J.Jowett 5/6
A scheme with 124 bunches/ring Collision pattern (scheduling)
• First bunches (again) of trains must NOT encounter at one of the exps (to have non colliding bunches)
• Collision patterns, if first bunches encounter (e.g.) at point 6
– Black: collisions– Red and Blue: bunches in ring 1
and 2 not colliding with bunch in other ring First bunch
(both rings)
Abort gapring 1
Abort gapring 2
LHC-BCWG, 28th September 2010 Filling Schemes proposed for the 2010 Ion Run C.Carli and J.Jowett 6/6