Proton Source Improvement Workshop Cogging W. Pellico Dec 6&7 2010

Booster Gap Three consecutive high intensity pulses (un-notched) will exceed extraction loss limit! – Booster creates a 3 gap notch – The gap is created using two pulsed kickers Notcher – High Voltage Kicker at Long 5 Nocker - Lower Voltage Kicker at Long 12 – Used to clean out Notched Beam – Required for Cogged Cycles – Beam is kicked into collimator region and Long 13 – The gap trigger is created and synched by modules in Booster Low Level room (several modules required) – Synchronization of gap can be done to Pre-Acc notching – Notch for non-cogged cycles occurs at 400 Mev – Cogged notch occurs at ~700 MeV

Gap Creation Scope Trace – Three Bucket Notch Uncogged Cycle – Notch Crated at Injection Cogged Cycle – Notch Created Later

Cogging Motivation Booster needs to fire (5) kickers in a (3 bucket) gap to keep losses down at extraction Booster syncs the gap to a MI marker (‘OAA’) Booster will extract on OAA +/- 1 bucket MI with circulating beam MI = 7*84 Bunches 3319 Meters

Cogging History Around 1998 – the first cogging studies (Webber, Pellico) – 2002: VXI board layout completed based upon early studies – 2005: Added additional automatic Update Trip Plan – 2006: Added BES over-ride – Multibatch MI operations High Intensity Cycles & Rates – Slip Stacking for Pbar Production – Slip Stacking for Numi – MI cycles used for Tevatron loading Cogged but not Notched

Wait for Booster To MI Event ($14 $19..) Was this the first event of load cycle Yes No Make a ‘Trip Plan’ Start Cogging Process End of cycle: Get ready for next Cogged CycleTrip Plan Cycle Start Tracking of Booster ‘Gap’ Create Gap Wait for ‘OAA’Track gap through cycle Calculate End of Cycle Gap Error Store gap position vs turn as reference Create GapSend MI a reset pulse to sync BES Calculate Gap Error Pre T cogging Extract on BES - GAP Post Transition Cogging Extract on ‘OAA’

Early Days

Current Typical Timeline $14 $19 $19 $19 $19 $14 $19 $19 $19 $19 $1D $1D $1D First Cycle For Trip Plan

Typical Plots Showing Cogging Rpos Variations for several MI Cycles Typically - Horizontal position will vary +/- 6mm (Depends upon gain setting ) There are two types of correction: Fixed and Proportional

July 27, 2004 Robert Zwaska Booster Cogging 10 Gap Position tracking Relative to Trip Plan Gap ~ 3 turns Slippage of Gap vs ‘Trip Plan’ Slippage in a cycle varies by > 200 buckets – About 3 circumferences Notch is essentially at a random position w.r.t the beam circulating in the Main Injector

Example of Booster system improvement to help cogging

Conclusion/Issues Dynamic Aperture – Beam Emittances – Beam Losses Higher losses on Cogged Cycles – Notch at Higher Energy – Gap not as clean – Orbit Control/Scraping Lots of hardware to maintain Jitter – Extraction and Gap Kickers Ready for Upgrade It works – much better then I would ever have hopped….