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!