1. Combined cleaning in IR3 - MD results and simulations Adriana Rossi R.W.Assmann, R. Bruce, F. Burkart, M. Cauchi, D. Deboy, L. Lari, S. Redaelli, G. Valentino, D. Wollmann A. RossiCWG 18 July 2011 1

2. IR3 combined cleaning MD Scope: Test cleaning efficiency when using IR3 for both momentum and betatron cleaning.  IR3 combined cleaning could be adopted if required for R2E.  Could reduce setup time.  Would reduce impedance. Procedure:  After beam based setup (see G. Valentino) in IR3.  Close TCP3 and TCS3 as for betatron nominal settings (if possible), i.e. TCP @ 5.7 , TCS @ 6.7 .  If possible keep TCTs as for physics (to test higher leakage to exp.).  Open TCP7 and TCS7.  Perform betatron and momentum loss maps in the H plane. Measurements performed:  Loss maps on horizontal plane, 3.5TeV with 1 nominal bunch, injection optics.  V collimators in IR7 left in since no vertical collimators in IR3.  Momentum loss maps could not be performed: beam dumped due to unmask-able BLM. 2 A. Rossi on behalf of the collimation team CWG 18 July 2011

3. IR3 combined betatron / momentum cleaning 3 What we would have (+ TCLA’s) What we could test (no vertical collimators in IR3) 10  6.7  5.7  Note that there are less passive absorber in IR3 (1 TCAP per beam) than in IR7 (3 per beam) TCHSH. 6L3.B1 TCSM. 5L3.B1 TCSM. 4R3.B1 TCSM. A5R3.B1 TCSM. B5R3.B1 TCP. A6L3.B1 TCP. 6L3.B1 TCSG. A5L3.B1 TCSG. 5L3.B1 TCSG. B4R3.B1 TCSG. 4R3.B1 TCSG. A5R3.B1 TCSG. C5R3.B1 TCSG. B5R3.B1 TCSG. D5R3.B1 Beam 1 Symmetric for Beam 2 TCSG. 5R3.B2 TCP. 6R3.B2 TCSG. 4L3.B2 Beam 2 TCSG. B5L3.B2 TCSG. A5L3.B2 TCLA. A5L3.B2 TCLA. 7L3.B2 TCLA. 6L3.B2 TCLA. B5L3.B2 A. Rossi on behalf of the collimation team CWG 18 July 2011

4. Results for IR3 combined cleaning, H, injection optics 4 B2 Setup apertures TCP3 (H) 5.7  TCS3 (H,S) 6.7  TCLA3 (H,V) 10  TCP7 (H,S) 18  TCS7 (H,S) 21  TCLA7 (H,S) 24  TCP7 (V) 5.7  TCS7 (V) 8.5  TCLA7 (V) 17.7  TCT (H,V) 26  TCL, TCLI, TDI open Main losses on TCP.6R3.B2 and TCSG.A5L3.B2 (skew) → Hierarchy? (TCP3 was tested to be the primary collimator prior measurements) High losses at TCTVs right of IR1 (~1%) and IR8 (~2.6%) IR7 and IR6 level A. Rossi on behalf of the collimation team ~2e-2 ~1e-2 ~1e-1 ~1e-2 CWG 18 July 2011

5. SixTrack simulations with collimators as thought to be 5 A. Rossi B2 TCP3 (H) 5.7  TCS3 (H,S) 6.7  TCLA3 (H,V) 10  TCP7 (H,S) 18  TCS7 (H,S) 21  TCLA7 (H,S) 24  TCP7 (V) 5.7  TCS7 (V) 8.5  TCLA7 (V) 17.7  TCT (H,V) 26  TCL, TCLI, TDI open SixTrack simulations with H sheet beam hitting TCP3: cannot reproduce IR3 loss shapes, nor high losses in IR1/8, nor IR6 and IR7 level CWG 18 July 2011

6. SixTrack simulations 6 TCP3 (H) 5.7  TCSG.A5L3.B2 5.7  TCS3 (H,S) 6.7  TCLA3 (H,V) 10  TCP7 (H,S) 18  TCS7 (H,S) 21  TCLA7 (H,S) 24  TCP7 (V) 5.7  TCS7 (V) 8.5  TCLA7 (V) 17.7  TCT (H,V) 26  TCL, TCLI, TDI open A. Rossi Sum of results: sheet beam hitting TCP.6R3.B2 and TCSG.A5L3.B2 ~1e-1 CWG 18 July 2011

7. Summary and future work Results:  After standard beam based setup in IR3.  H betatron loss maps dumped both beams.  Measured loss map pattern different from usual: Main losses on TCP.6R3.B2 and TCSG.A5L3.B2 (skew) → Hierarchy? But prior measurements TCP3 was moved in to verify it was the primary collimator. High losses at TCTVs right of IR1 (~1%) and IR8 (~2.6%). IR6 and IR7 and level.  Simulated loss map pattern could partly be reproduced by overlapping results from “hierarchy breakdown” and sheet beam hitting both collimators with highest losses. Further study to interpret/reproduce data. After analysis (simulations also with FLUKA to include showers) measurements should be repeated to validate scheme. 7 A. Rossi on behalf of the collimation team CWG 18 July 2011