AP2 & Debuncher Acceptance

1. AP2 & Debuncher Acceptance Keith Gollwitzer Director’s Review January 21, 2004

2. V. Lebedev October 2001 The Bottom Line Present`p yield: 1610-6`p/POT Expected`p yield: 3610-6`p/POT  52 1010`p/hr Delivered to the Accumulator for stacking For: 81012 POT/pulse (slip stacking) 2.0 sec cycle time AP2 & Debuncher Acceptance – Keith Gollwitzer

3. 10 0 Angle (mrad) -10 -10 0 10 Position (mm) Goal: Lots of Pbars into Debuncher < 20 mm-mrad 20-40 mm-mrad > 40 mm-mrad Simulation of pbar transverse phase space (both planes) out of a 750 T/m lens. {2 entries for each pbar that only traverses Lithium part of lens} Collect as much as possible for Debuncher cooling systems AP2 & Debuncher Acceptance – Keith Gollwitzer

4. Admittance Measurements Shottkey power (linear scale) Shottkey power (log scale) Lossmonitors Takes many stacking cycles; >0.5hr Beam Edge Extinction Beam Edge Extinction Old Method Debuncher horizontal scraper position (mm) Debuncher horizontal scraper position (mm) Circulating Admittance done by scraping heated reverse proton beam: Well defined edge and extinction(p/p ~ 0) Operational Admittance done by scraping while stacking: Hard to define Beam edge & extinction (p/p is full mom. spread) AP2 & Debuncher Acceptance – Keith Gollwitzer

5. Operational Admittance Measurements • Make separate (few minute setup) measurements of the beam edge and extinction point • lengthen the production cycle time to 10’s seconds • Cooling turned OFF Shottkey power Extinction Spectrum Analyzer for several scraper positions Extinction Point: Schottkey power sampled seconds after injection versus Debuncher scraper; Spectrum Analyzer goes from flat line to small step in the 0.1box of left plot above Beam Edge Beam edge: Run scraper into beam between cycles starting a few seconds after injection; record loss monitors as function of scraper position AP2 & Debuncher Acceptance – Keith Gollwitzer

6. AP2 & Debuncher Acceptance – Momentum Acceptance Longitudinal Schottky profile of`p’s filling the momentum aperture of the Debuncher. Bunch rotation and stochastic cooling are off. NOTE: An earlier (11/2002) measurement gives Dp/p = 4.6% AP2 & Debuncher Acceptance – Keith Gollwitzer

7. AP2 & Debuncher Acceptance -- Parameters † AP2 + Debuncher admittances reported at the July 2003 review were: Horizontal: 20 p mm-mrad, Vertical: 12 p mm-mrad *Debuncher admittancesreported at the July 2003 review were: Horizontal: 25 p mm-mrad, Vertical: 20 p mm-mrad **Design Goal is 40 p horizontal and vertical admittance everywhere within a ±2.00% momentum acceptance AP2 & Debuncher Acceptance – Keith Gollwitzer

8. Goal: Realization of 35 mm-mrad Plan: Identify & Understand Restrictions Documentation Research Optical Survey Lattice Modeling Instrumentation Beam Studies Mitigate Redesign/modify/rebuild specific elements Align/relocate specific elements Beam Based Alignment Lattice Model Instrumentation Orbit control Beam Studies AP2 & Debuncher Acceptance – Keith Gollwitzer

9. Identify Restrictions Building detailed lattice models Tech Div is performing documentation research Verifying drawings with components Produced tables of all apertures Optical Survey Determine alignment of AP2 & Debuncher components Determine alignment of AP1, target hall & AP2 Verify lattice parameters Beam studies using upgraded instrumentation Models (OptiM & MAD) Local & LBNL investigations Identify restrictions and orbit control tolerances Propose resolutions Final Checkout Data 90% taken Crunch numbers Continue to feed into models AP2 & Debuncher Acceptance – Keith Gollwitzer

10. 25 p mm-mrad Acceptance V. Lebedev November 2001 40 p mm-mrad Acceptance OptiM Modeling of AP2 Acceptance AP2 & Debuncher Acceptance – Keith Gollwitzer

11. MAD Model and Studies by LBNL LBNL: I. Reichel & M. Zisman AP2 & Debuncher Acceptance – Keith Gollwitzer

12. MAD Simulations and Studies by LBNL AP2 & Debuncher Acceptance – Keith Gollwitzer

13. Mitigation of Restrictions Known/Suspect AP2 momentum collimator Either scraper is moved: decrease of acceptance Investigating whether the collimator gap can be increase and how well matched the collimator is matched to pipe. Need to do? D4Q4 replacement & BPM removal/relocation ~No vertical tolerance for injected beam 2 large spare quad LQBs will replace quad; same integrated field and fits into space. Need stand work; have existing power supply. Motorize stands for septum & kickers Tolerances are small; desire to center devices Engineering will start by looking at existing tank motorized stands. Injection septum (common vacuum chamber) Desire injected beam to be close to closed orbit Investigating whether spare can be reworked to minimize material at down stream end. Change from build to using spares AP2 & Debuncher Acceptance – Keith Gollwitzer

14. Beam direction D4Q4 Aperture No tolerance for injected beam. Replace with large quad LQBs; increase vacuum chamber by 20%. Remove BPM from upstream area. AP2 & Debuncher Acceptance – Keith Gollwitzer

15. Mitigation of Restrictions Known/Suspect continued Band 4 cooling tanks arrays Array separations were designed for ~30 mm-mrad Investigating whether can open array gap at the frequencies of Band 4. An alternative is to remove half of the arrays per tank. Move DRF2 & DRF3 to low dispersion region Radiation surveys show activation -DRF3 has been moved to low dispersion. -Looking into different schemes of where to locate DRF2 and essential electronics. Other mitigations Identification and solutions may have to wait for modeling, beam studies and/or implementation of above. Identified that the extraction kicker’s elliptical pipe is 22 and 36 apertures for off momentum particles. Appears that inserting a rectangular beam pipe will be sufficient. Recently Identified AP2 & Debuncher Acceptance – Keith Gollwitzer

16. Beam Size (mm) Band 2 Band 1 Band 4 Band 3 HorzVert Physical Apertures Debuncher Band 4 Arrays Aperture Beam sizes calculated for 40 mm-mrad Arrays are motorized to be centered about beam AP2 & Debuncher Acceptance – Keith Gollwitzer

17. Debuncher Extraction Kicker Upstream End – Beam Profile First Turn in Debuncher– Downstream End 82% of tracked beam particles inside of ellipse. Rectangle of same inner dimensions accepts 91%. Increase horizontal dimension will accept 95%: Looking into offsetting pipe in kicker, but beam fairly small when extracting (good field region?) Increase vertical dimension is ~2% per mm; what does gap allow. AP2 & Debuncher Acceptance – Keith Gollwitzer

18. AP2 & Debuncher Acceptance ––Limiting Apertures †DRF3 was moved during the Fall 2003 shutdown and is no longer an aperture restriction. Table gives pre-move admittances. AP2 & Debuncher Acceptance – Keith Gollwitzer

19. Instrumentation Upgrades BPM systems Old original electronics and DAQ. Reliability, maintenance and ease of use are issues AP2 (desire <100m resolution) 53MHz Minimum is DAQ and software replacement Still need to see if RF electronics are sufficient Debuncher (~50m resolution) 2.5MHzClosed Orbit system (elec., DAQ & software) Commissioned; making user friendly AP2 & Debuncher Acceptance – Keith Gollwitzer

20. Instrumentation Upgrades Other Re-install AP2 709 horizontal collimator Was re-installed; no beam studies yet AP2 large aperture Toroid(s) Beam intensity measurement along beam line Started discussions with vendor New Move SEMs for optimal phase advance(?) Other instrumentation as needed AP2 & Debuncher Acceptance – Keith Gollwitzer

21. Existing AP2 Instrumentation AP2 & Debuncher Acceptance – Keith Gollwitzer

22. Existing Debuncher Instrumentation New System commissioned AP2 & Debuncher Acceptance – Keith Gollwitzer

23. Orbit Control AP2 Started with 4H+4V trims Have added 1H+3V trims Installed shunts on all dipoles of left bend Can add more trims as needed Debuncher Started with 13H+7V trims Started with 2 vert. plane motorized quads Have added 5 two plane motorized quads Added 10 two plane motorized quads (03) Adding 20 two plane motorized quads (04) No available space for trims; the ring is packed Beam time needed to finish local bump commissioning AP2 & Debuncher Acceptance – Keith Gollwitzer

24. Beam Based Alignment & More Basic BBA Procedure Excite a quad Most quads have shunts Measure response BPM systems for proton studies A Debuncher pickup for AP2 during stacking Correct Orbit Trims, shunts, motorized quad stands Other Study Programs Heat protons in Deb and watch BLMs Paint the Debuncher aperture Prepare known emittance/momentum reverse proton beam & kick beam up AP2. AP2 & Debuncher Acceptance – Keith Gollwitzer

25. Debuncher TBT Instrumentation Used for closure of AP2 injection QS730 changed by 16Amps With quad shunts, orbit through the quad centers can be determine during stacking Polar Plot: Oscillation Amplitude (arb. Units) and Phase of oscillation at pickup AP2 & Debuncher Acceptance – Keith Gollwitzer

26. Paint the Aperture Not Fully debugged- commissioned in 1999-2000 for Debuncher. For each corrector, kick until beam is extinguished: then have “painted” the aperture. Program has no assumptions about beam emittance and distribution, so need to extinguish beam  each corrector reach is then only about ~4 Possible Solutions: 1) Be able to prepare beam to known emittance & distribution consistently before exciting any trim. 2) Use combinations of trims to map out more of the aperture. The former needs much study time to see if possible; the latter solution shows promise on paper…. AP2 & Debuncher Acceptance – Keith Gollwitzer

27. Summary Beam Based Alignment will be more useful: Upgrade instrumentation Better orbit control AP2 beam line Had 13 knobs, have added 10, can add a few more Debuncher ring Had 22 knobs, have added 30, will add 40 more Our understanding of the lattices improve and the physical apertures & tolerances Upgrade/new software applications Will have to mitigate limiting apertures Redesign/modify/rebuild/relocate AP2 & Debuncher Acceptance – Keith Gollwitzer