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Wirescanner Status. Guy Crockford BE/OP LBOC 11/10/11. Content. Front End improvements Beam 1: 200MHz noise suppression Intensity limit at injection energy Bunch selection gate limitations Application Software improvements… Tools for bunch selection - PowerPoint PPT Presentation
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Wirescanner Status
Guy Crockford BE/OPLBOC 11/10/11
Content
• Front End improvements– Beam 1: 200MHz noise suppression– Intensity limit at injection energy– Bunch selection gate limitations
• Application Software improvements…– Tools for bunch selection– Display of multiple bunch normalized emittance– General layout
Beam 1: 200MHz Noise
Beam 1: 200MHz noise
• Source of noise not yet understood• Few opportunities for access/investigation
• Remove with simple filtering technique…– For each wirescan acquisition…– Add gate to acquire noise signal in the abort gap– Subtract signal acquired from measurements in
gates with beam
WS measurements @ horizontal scrappingCorrection due to noise
B1 profile: ~200Hz noise hides the profile
B1 profile: Noise reduced by deducting the acquisition of a bunch slot belonging to the abort gap & acquired at the same time
Sigma from noisy profiles
Sigma from cleaned profiles
Intensity curve
Acq stamp (ns) Acq stamp (ns)
Sigm
a (u
m)
Sigm
a (u
m)
The Sigma curve follows Intensity curve in H plane. The overall measurement spread for the corrected profiles is significantly reduced
Sigma spread with filteringLHC.BWS.5R4.B1H2 Sigma
Scan results with filtering
Intensity limit at injection• Wire damage threshold (higher limit)
• BLM trigger threshold (more sensitive)– Previously set to 2.1E13 at 450GeV– We need to scan 12+144 nominal bunches– Hitting limit at bunch intensity > 1.34E11
• Increase limit to 2.5E13 at 450GeV– Effective bunch intensity limit raised to 1.6E11
Acquisition gate limitation issues
• Previously acquisition gate limited to 30 bunches
• Firmware bug…– Only ¼ of DAB card memory exploitable
• Firmware problem solved and number of turns for 1 acquisition reduced from 1000 to 500
• Now able to set the acquisition gate to measure 156 bunches in 1 scan
Tools for gate selection
• Need to quickly check emittances at the start of the physics filling process– 12 bunch batch & first 144 bunch batch
• Buttons added to application to select the correct batch (based on nominal filling scheme)
• Buttons to save and recall user defined bunch selections to file
Bunch selection options
Bunch selection options12 Bunch Batch
First 144 Bunch Batch
Emittance ChartNormalized Emittance vs Slot number
Multiple fit calculation• Slow to calculate fits for 156 bunches• Enable multiple fit calculation for all bunches only if required
Fit All profiles
Fit Only Visible Profiles
Settings Menu• All key settings controlled from front panel
Acknowledgments
• Thanks to…– BE/BI: • Ana Guerrero, Federico Roncarolo, • Mariusz Sapinski, Johnathan Emery
– Fermilab LAFS: • Elliott McCrory
• Thanks for your attention!