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Booster Digital DamperStatus & Plans

Nathan Eddy

PIP Meeting12/21/11

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Motivation• Implement a bunch by bunch digital feedback

system FPGA, ADC, Digital Signal Processing, DAC Wideband system Flexibility to modify system as needed

• Essentially an R&D project up to nowDemonstrate transverse system operation Diagnostic capability – tune, studies, etcDevelop plan for longitudinal system

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Transverse Damper System Overview

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VME Digital Damper Board

• Large Stratix II FPGA handles signal processing & interfaces on multiple clock domains

• 4 ADC (up to 212MHz) & 4 DAC (up to 636MHz) locked to external RF

• Digital I/O – TCLK, MDAT, BSYNC decoders, fanout, diagnostics

• Up to 1GB on-board RAM• VME front-end speaks ACNET• Used in Recycler – Transverse

Damper, RF Correction, ACBeam Intensity

• Used for MI Anti-proton Injection Damper

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Current Transverse Setup

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Logic & Control

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Initial Testing Results

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Horizontal Instability Study

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Tune Monitor

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Tune Spectra

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ACNET Config & Control

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Diagnostic Capability

• Record bunch by bunch data for entire Booster cyclePosition, Intensity, Phase

• Measure Booster revolution frequency1Hz resolution @1ms

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Issues• Horizontal response is not

optimal due to pickup & kicker locations

• Difficulty exciting beam horizontally after transition Chromaticity Power

• RF Clock Lock Causes PLLs for

ADC/DAC to relock Requires re-phasing

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The Future• Transverse Damper currently is not needed for

operation – driven largely by R&D right now• Continue to gain operational experience with

Transverse Damper Can we lower Chromaticity? Do we require more power in the horizontal plane?

• Investigate options for moving horizontal pickup & kicker and/or adding additional pickups Ideal scenario is two pickups ~90 degrees apart Is our current stripline pickup ideal? Use BPMs?

• Begin to investigate options for longitudinal damper

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Budget Estimates?

• Damper Upgrade Parts purchased for 1GS/s high BW proto-type 1 year and $5k to produce prototype Can we go after head/tail effects – kick?

• Possibility for new pickups Pickups & Cables ~$10-20k

• Possibility new amplifiers are required Real dollars ~$100k

• Longitudinal Damper (???)