1. 14/01/2005M. Giovannozzi - PS-SPS Days1 When can we have a clean Multiturn Extraction from the PS? M. Giovannozzi M. GiovannozziContentIntroduction Summary of experimental results Implementation: resources Implementation: time scale Implementation: additional experimental activities

2. 14/01/2005M. Giovannozzi - PS-SPS Days2 Main contributors to the study Study Group members Study Group members AB/ABP: O. E. Berrig, S. Gilardoni, M. Martini, E. Métral. AB/BT: T. Fowler, K.-D. Metzmacher, L. Sermeus. AB/OP: R. Steerenberg. AB/PO: J.-P. Burnet. AT/MEL: W. Kalbreier. Acknowledgments: Discussions, support: G. Arduini, R. Garoby, J.-P. Riunaud. Operations: PSB and PS specialists.

3. 14/01/2005M. Giovannozzi - PS-SPS Days3 Introduction Since the year 2002 intense efforts were devoted to the experimental verification of the proposed multiturn extraction based on beam capture inside stable islands. At beginning of 2004 the first report of the Study Group was issued. On December 6 th 2004 a status report of the studies (experimental and implementation) was made at the ABMB. A decision concerning the future of this study is expected to be taken by ABMB on January 24 th.

4. 14/01/2005M. Giovannozzi - PS-SPS Days4 Experimental results (reported at APC meeting 03/12/04) - I Capture and separation of high-intensity (6×10 12 p), single-bunch beam (nominal case) 1.No losses, capture 12 % in each of the four beamlets. 2.2-3% losses, capture about 18 % (detailed data analysis in progress). Results at points 1. and 2. were obtained without any constraint on the time available for trapping and separation. 3.Process compatible with 900 ms operation, i.e. performance comparable with that of point 2, but with trapping and separation performed in 60 ms. Ramp of nonlinear elements should occur at the end of acceleration (five-current working point control crucial). Extraction Currently installed hardware does not fit our needs.

5. 14/01/2005M. Giovannozzi - PS-SPS Days5 Experimental results (reported at APC meeting 03/12/04) - II Capture losses are reduced to zero… Horizontal beam profile Depleted region: extraction septum blade will not intercept any particle

6. 14/01/2005M. Giovannozzi - PS-SPS Days6 Implementation: Capture, separation Sextupoles and octupoles: new elements are needed for operational version (varying the strength while keeping islands’ phase at extraction septum constant). PS sextupoles are available. SPS octupoles should be available (discussions on-going with AT/MEL). Power converters: two TEKELEC are available, but they are hot spares for operational hardware (dipoles DHZ15 and DHZ60, the high-energy orbit correctors). They can be used in 2006. Afterwards new power converters are required: 0.20 MCHF (power converters) + 0.05 MCHF (cabling) Definition of sections where to install the magnets: requires studies from ABP (activity resumed in December).

7. 14/01/2005M. Giovannozzi - PS-SPS Days7 Implementation: Beam instrumentation A new wire scanner will be required in the horizontal plane (tomography and beamlets position at extraction): Availability is under evaluation: reply from AB/BDI is expected by third week of January. Definition of section where to install the device: requires studies from ABP (activity resumed in December).

8. 14/01/2005M. Giovannozzi - PS-SPS Days8 Implementation: Extraction New layout studied. It is based on Slow bump around septum 16: same magnets as presently installed, but new power converters are required (4+1 spare): 0.35 MCHF (power converters), 0.10 MCHF (infrastructure and cabling), 1 man-year Minimum time: 24 months Fast bump around septum 16: kickers in sections 9, 13, 21 => first four turns kickers in sections 64, 72 => fifth turn Such a configuration is compatible with present CT! Detailed verification of performance of extraction layout (e.g. acceptance of the machine for second island at first turn) needed: requires studies from ABP (activity resumed in December).

9. 14/01/2005M. Giovannozzi - PS-SPS Days9 Beamlets trajectories before extraction New elements: kick64, kick72, kick13, kick21 (fast bumpers)

10. 14/01/2005M. Giovannozzi - PS-SPS Days10 Beamlets trajectories at extraction Extraction channel New elements: kick64, kick72, kick13, kick21 (fast bumpers)

11. 14/01/2005M. Giovannozzi - PS-SPS Days11 Implementation: Kickers - I Two stage solution: Stage 1: recuperated kickers; slow rise time (350 ns rise time 10%-90% for first four turns; 160 ns 10%-90% for fifth turn); Stage 2: upgraded kickers (160 ns rise time 10%- 90% for all five turns) compatible with h=8 operation; Single stage solution: Jump directly to Stage 2.

12. 14/01/2005M. Giovannozzi - PS-SPS Days12 Machine circumference Estimate of extraction losses - I Septum location Septum width (  ) Relative losses (%) Black: continuous beam Red: bunched beam (h=8, bunch length 100 ns - measured) Blue: bunched beam (h=16, bunch length 80 ns – educated guess) Losses due to septum traversal at first and fifth turn for stage 1 Assumptions Gaussian distribution (transverse) Parabolic distribution (longitudinal)

13. 14/01/2005M. Giovannozzi - PS-SPS Days13 Estimate of extraction losses - II Losses (%) Continuous Bunched (h=16) Bunched (h=8) Stage 1 10.90.6 Total (capture+extraction) 3-42.9-3.92.6-3.6 Stage 2 0.60.5 < 0.1 Total (capture+extraction) 2.6-3.62.5-3.52.1-3.1

14. 14/01/2005M. Giovannozzi - PS-SPS Days14 Implementation: Kickers - II Two stages solution Stage 1: 2.2 MCHF 3 man-years Minimum time: 18 months Stage 2: 7.3 MCHF 5 man-years Minimum time: 18 months Additional costs 0.35 MCHF (equipment replacement) If only stage 1 is implemented, then 0.80 MCHF (equipment replacement) Single stage solution 8.5 MCHF 7 man-years Minimum time: 24 months Can we expect some support (manpower) from other Labs? Preliminary contacts between Physicists (OPERA) and Frascati Director. No further news so far…

15. 14/01/2005M. Giovannozzi - PS-SPS Days15 Implementation: Kickers - III Critical issues Minimum time estimates are probably too optimistic. A correction factor should be applied (1.5-2). Availability of design office might be an issue. Safety measures require careful investigation. Two stages solution: the impedance as seen by the beam for the first stage should be evaluated. Measurements are being organised (F. Caspers et al.): they should start by end of March. Preliminary results are expected by beginning of May. In case of serious problems, this might force choosing the single stage solution. Otherwise, appropriate measures could be implemented in stage 2 (additional costs?). Single stage solution: structural modifications to building 367 required and subsequent infrastructure. Coordination will be a challenge (many activities in parallel). Costs are taken into account (AB/BT estimate).

16. 14/01/2005M. Giovannozzi - PS-SPS Days16 Implementation: Vacuum Support from AT/VAC is needed for: Kicker installation. Additional wire scanner. Modifications to the vacuum chamber to improve the aperture in critical regions (mainly extraction). The definition of sections with modified aperture is linked to studies of the extraction layout in ABP (activity resumed in December). Present status does not allow for evaluating any accurate cost estimate and manpower needed. However, as a general remark: Material procurement might be an issue (1 year delay). Availability of design office.

17. 14/01/2005M. Giovannozzi - PS-SPS Days17 Summary of resources needed Hardware (+FSU) MCHFPersonnel(man-years) Power converters 0.71 Kickers Two stages 9.58 Grand total 10.29 Kickers Single stage 8.57 Grand total 9.28

18. 14/01/2005M. Giovannozzi - PS-SPS Days18 Possible time scales 24 months t0t0t0t0 Installation of sextupoles and octupoles in final locations. Further tests with beam in 2006? Installation completed (power converters and kickers) Tests with beam in parallel with CT Single stage scenario 24 months t0t0t0t0 Installation of sextupoles and octupoles in final locations. Further tests with beam in 2006? Stage 1 completed (power converters and kickers) Tests with beam in parallel with CT t1t1t1t1 Stage 2 completed (kicker upgrade) 18 months Two stages scenario t 1 +6 months: CT elements dismantled Value of t 0 is mainly driven by manpower!

19. 14/01/2005M. Giovannozzi - PS-SPS Days19 Future experimental activities? In 2006 most of the hardware required will not be ready. Only sextupoles and octupoles might be available in their final locations. This allows for a number of tests to be performed: At PSB (already in 2005?): Try generating a beam with large horizontal emittance (to improve capture) and small vertical emittance (to reduce nonlinear coupling between H/V planes). At PS: Try reducing the losses observed when the fraction of particles trapped in the islands approaches 20 %. Attempt to use the transverse feedback to control the horizontal emittance of the injected beam.