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Tevatron Collider II Halo Removal System Dean Still Fermilab Tevatron Department 7/22/2003 • Motives Tevatron Collider II Halo Removal System Dean Still Fermilab Tevatron Department 7/22/2003 • Motives for the Collider Run II Collimator Halo Removal System upgrade. • Halo Removal System Overview. • Halo Removal Performance. • Upgrades and future plans. D. Still-FNAL/Tevatron DOE Review 7/2003

Collimator System Upgrades for Run -II • Wanted to move to commercial hardware to Collimator System Upgrades for Run -II • Wanted to move to commercial hardware to replace in house motion controls. – Collimators are faster and more reliable. – Each Collimator would be able to do feedback processing. • Wanted to move to a more automated system to reduce shot setup time and integrate controls with the Collider Sequencer. – Goal was to shot setup Halo Removal times of about 5 min. (TM 1961 March 1996) • Wanted to move to a 2 stage collimator halo removal system. – Build 4 new targets and 8 new secondary collimators. D. Still-FNAL/Tevatron DOE Review 7/2003

2 Stage Collimator System Collimator Scattered trajectories Target @ ~5 s 6 inch Target 2 Stage Collimator System Collimator Scattered trajectories Target @ ~5 s 6 inch Target w/ 5 mm Tungsten Wing Collimator @~6 s N. Mokhov et. al, “Tevatron Run-II Beam Collimation System” , Proc. PAC 1999, or Fermilab-Conf -99/059. 1. 5 m collimator D. Still-FNAL/Tevatron DOE Review 7/2003

Tevatron Collimator Layout 12 collimators total: 4 Targets 8 Secondary collimators Arranged in 4 Tevatron Collimator Layout 12 collimators total: 4 Targets 8 Secondary collimators Arranged in 4 sets: 2 proton sets 2 pbar sets Proton Set 1 D 49 Tar, Proton Set 2 D 171 Tar, Pbar Set 1 F 49 Tar, Pbar Set 2 F 173 Tar, E 03 & F 172 2 nd D 173 & A 0 F 48 & D 172 F 171 & E 02 D. Still-FNAL/Tevatron DOE Review 7/2003

Collimator Controls Hardware • Uses VME based processor. • LVDT’s for position reading. • Collimator Controls Hardware • Uses VME based processor. • LVDT’s for position reading. • Commercial Motor drives • Standard Tevatron loss monitor hardware for feedback. • Uses beam intensity feedback for FBI encoded on MDAT. • 12 VME processors controlled by upper layer of software. D. Still-FNAL/Tevatron DOE Review 7/2003

Merit of Halo Removal Efficiency CDF proton halo loss reduced by factor of 9 Merit of Halo Removal Efficiency CDF proton halo loss reduced by factor of 9 CDF pbar halo loss reduced by a factor of 28 D 0 proton halo loss reduced by a factor of 1 D 0 pbar halo loss reduced by a factor of 100 D 49 Target position F 172 Hor Coll. position CDF proton Halo counter CDF pbar halo counter D. Still-FNAL/Tevatron DOE Review 7/2003

Effects of reducing spikes on proton halo losses with TEL ON DC Beam Intensity Effects of reducing spikes on proton halo losses with TEL ON DC Beam Intensity CDF proton halo loss CDF Muon Losses D. Still-FNAL/Tevatron DOE Review 7/2003

Addition of A 48 Collimator to Protect against A 0 abort kicker prefires Date Addition of A 48 Collimator to Protect against A 0 abort kicker prefires Date # Prefires Run I 4/1994 11/1995 6 Run II 3/2001 present 7 A 11 V collimator Already in place A 0 proton abort kickers Add. 5 m Collimator at A 48 to shield against prefires D. Still-FNAL/Tevatron DOE Review 7/2003

Possible Future Upgrade: Crystal Collimation Due to increased intensities and losses due to beam-beam Possible Future Upgrade: Crystal Collimation Due to increased intensities and losses due to beam-beam effects may need to implement crystal system. Lost during 200 turns Passed through Rom Pots upstream of D 0 upstrea m of B 0 lost in coll. E 03 lost in coll. F 17 2 channelin g efficiency % Collimation w/ primary 5 -mm thick tungsten collimator at D 49 If particles entering a crystal are properly aligned to the crystal planes, they will follow the planes, even if the crystal is bent. Work from R. Fliller, BNL. 0. 9248 0. 01178 0. 00401 0. 4088 0. 3218 NA Collimation w/ 5 -mm thick silicon crystal at E 0, bending angle =. 0. 15 mrad amorphous layer=0 mm hor. Alignment =9 mrad 0. 9786 0. 0004 0. 0006 0. 9415 0. 0284 96. 21 amorphous layer=1 mm hor. Alignment =9 mrad 0. 8308 0. 00022 0. 0012 0. 7556 0. 0562 90. 85 amorphous layer=2 mm hor. Alignment =9 mrad 0. 7331 0. 0003 0. 0012 0. 643 0. 066 87. 71 amorphous layer=1 mm hor. Alignment =7 mrad 0. 8261 0. 0004 0. 0008 0. 7461 0. 064 90. 32 amorphous layer=1 mm hor. Alignment =11 mrad 0. 8252 0 0. 0018 0. 7413 0. 059 89. 83 Collimation w/ 45 -mm thick silicon crystal at E 0, bending angle =. 0. 37 mrad amorphous layer=1 mm hor. Alignment =9 mrad 0. 9351 . 00051 . 0021 0. 7300 0. 1364 Simulated Loss results from Drozhdin & Mokhov, FNAL D. Still-FNAL/Tevatron DOE Review 7/2003 78. 07

In Closing: • The design and implementation of the collider II halo removal system In Closing: • The design and implementation of the collider II halo removal system has worked well as far as reliability, speed , ease of use and status mechanics of conducting halo removal. • The process is entirely automated. Process takes routinely 12 min to complete but has been done as fast as 7 min. • The systems effectiveness at reducing proton and pbar halo loss is reasonable and within limits set by CDF and D 0. • The TEL is an operational must in order to reduce spikes in CDF proton halo losses and remove DC beam accumulated in the abort gaps through out the length of a store. • Attempts are being made to understand improve overall vacuum. • An additional. 5 m collimator will be installed at A 48 in order to reduce kicker prefires. • Possibility of future implementation of a crystal collimator at E 0. D. Still-FNAL/Tevatron DOE Review 7/2003

Collimator System Upgrade Designs for Collider II New design for the collimator system came Collimator System Upgrade Designs for Collider II New design for the collimator system came from: Tevatron Run-II Beam Collimation System A. I Drozhdin and N. V. Mokhov This paper along with the experience from Run-I was the basis for designing the controls and sequence of motion for the Tevatron collimator system. D. Still-FNAL/Tevatron DOE Review 7/2003

Collider II 1. 5 m Collimator D. Still-FNAL/Tevatron DOE Review 7/2003 Collider II 1. 5 m Collimator D. Still-FNAL/Tevatron DOE Review 7/2003

Collider II Target with 5 mm Tungsten wing. D. Still-FNAL/Tevatron DOE Review 7/2003 Collider II Target with 5 mm Tungsten wing. D. Still-FNAL/Tevatron DOE Review 7/2003

Collider II 1. 5 m E 0 Secondary Collimators. D. Still-FNAL/Tevatron DOE Review 7/2003 Collider II 1. 5 m E 0 Secondary Collimators. D. Still-FNAL/Tevatron DOE Review 7/2003

Tunnel Layout of Collimator Local Loss Monitors used for proton losses Local Loss Monitors Tunnel Layout of Collimator Local Loss Monitors used for proton losses Local Loss Monitors used for pbar losses F 17 Spool F 171 Collimator F 172 Collimator F 17 Kicker F 173 Target Protons D. Still-FNAL/Tevatron DOE Review 7/2003 F 17 Dipole

Overview of New Software N*s X 0 Front End Fast Processing : Loss Monitor Overview of New Software N*s X 0 Front End Fast Processing : Loss Monitor & Intensity Feedback. D. Still-FNAL/Tevatron Xi OAC Application Global Orchestration: Configure/view, Initiate Process: Employs states and collimator moving map. Can use sequencer initiate scraping. DOE Review 7/2003

C 10 - Controlling one Collimator The left side portrays the details of the C 10 - Controlling one Collimator The left side portrays the details of the movement for D 49 H 1 target for Begin Halo Removal. D. Still-FNAL/Tevatron DOE Review 7/2003

Tevatron Shot Setup Process Inject 36 final protons Open Helix & Inject 9 Trans Tevatron Shot Setup Process Inject 36 final protons Open Helix & Inject 9 Trans of 4 Pbar bunches Accelerate Goto Lowbeta Remove Halo D. Still-FNAL/Tevatron DOE Review 7/2003

Example of D 49 movement during Halo Removal Process Fine Scrape process: Scrapes. 4% Example of D 49 movement during Halo Removal Process Fine Scrape process: Scrapes. 4% of proton beam Find the edge of the beam Retracted ~ 40 mils or 1 mm Before Halo removal CDF proton loss Initial Move No feedback After Halo Removal CDF proton loss D. Still-FNAL/Tevatron DOE Review 7/2003

Proton & Pbar Targets moving during Halo Removal Proton bunched beam intensity D 49 Proton & Pbar Targets moving during Halo Removal Proton bunched beam intensity D 49 local BLM Pbar bunched beam intensity F 49 local BLM D. Still-FNAL/Tevatron DOE Review 7/2003

CDF & D 0 Proton Halo Loss vs. Proton Intensity D 0 Proton Halo CDF & D 0 Proton Halo Loss vs. Proton Intensity D 0 Proton Halo Loss CDF Proton Halo Loss D. Still-FNAL/Tevatron DOE Review 7/2003

CDF & D 0 Pbar Halo Loss vs. Pbar Intensity CDF Pbar Halo Loss CDF & D 0 Pbar Halo Loss vs. Pbar Intensity CDF Pbar Halo Loss D. Still-FNAL/Tevatron D 0 Pbar Halo Loss DOE Review 7/2003

F 172 Horizontal Retraction Scan (with D 49 target in) Into the beam CDF F 172 Horizontal Retraction Scan (with D 49 target in) Into the beam CDF proton halo loss F 17 local loss monitor D. Still-FNAL/Tevatron DOE Review 7/2003

Halo losses and collimator angle Beam 1. 5 m collim ator Good if < Halo losses and collimator angle Beam 1. 5 m collim ator Good if < 10 mils difference from upstream to downstream. Live with >10 and <30 mils difference from upstream to downstream. Bad if > 30 mils difference from upstream to downstream. D. Still-FNAL/Tevatron DOE Review 7/2003

Typical halo losses during store 2549 D 0 proton halo D 0 pbar halo Typical halo losses during store 2549 D 0 proton halo D 0 pbar halo CDF proton halo CDF pbar halo D. Still-FNAL/Tevatron DOE Review 7/2003

Collider Run II History of Experiences Date Events June 2001 Used Automatic Halo removal Collider Run II History of Experiences Date Events June 2001 Used Automatic Halo removal system for first time Aug 2001 • CDF experiencing power supply failure to crates on. • CDF sees “spikes” on proton halo losses and muon chambers. Dec – Jan 2001 • Tevatron quenches on abort due to DC beam. • “Spikes” on CDF proton halo loss persist. Jan-June 2002 Experience proton halo loss growth during stores due to poor F 11 vacuum. Feb 2003 • CDF added shielding at proton end of detector. • Tevatron removed C 0 Lambertson- known aperture limit. March 2003 Rash of A 0 abort kicker prefires lead to addition of A 48 collimator. D. Still-FNAL/Tevatron DOE Review 7/2003

Retracting F 172 H effects losses in Muon chambers at CDF Muon Chamber Loss Retracting F 172 H effects losses in Muon chambers at CDF Muon Chamber Loss Retreact F 172 collimator D. Still-FNAL/Tevatron DOE Review 7/2003

DC Beam at Collisions A 4 DC beam monitor 36 proton bunches Abort Gap DC Beam at Collisions A 4 DC beam monitor 36 proton bunches Abort Gap D. Still-FNAL/Tevatron DOE Review 7/2003

TEL getting rid of DC beam CDF Proton Halo loss DC BEAM Intensity Proton TEL getting rid of DC beam CDF Proton Halo loss DC BEAM Intensity Proton Bunched Beam TEL ON D. Still-FNAL/Tevatron DOE Review 7/2003

CDF Proton Halo loss “spikes” correlated to horizontal orbit motion CDF proton halo Loss CDF Proton Halo loss “spikes” correlated to horizontal orbit motion CDF proton halo Loss counter Out of single BPM Processed to provide Orbit motion. Hor and Ver D. Still-FNAL/Tevatron DOE Review 7/2003