1 / 36

Results from the DAΦNE Tests Catia Milardi (on behalf of the DA  NE Team) SuperB Workshop

This paper outlines the results from the DAΦNE Tests conducted at the SuperB Workshop in LAL, Orsay, in February 2009. It discusses the original configuration overview, the new collision scheme and collider upgrade, issues related to DAΦNE commissioning, recent luminosity breakthrough, optics refinement, beam dynamics studies, subsystem developments, and concludes with the findings.

rickym
Download Presentation

Results from the DAΦNE Tests Catia Milardi (on behalf of the DA  NE Team) SuperB Workshop

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Results from the DAΦNE Tests Catia Milardi (on behalf of the DANE Team) SuperB Workshop LAL, Orsay, February 15-18, 2009

  2. DAFNE Collaboration Team D.Alesini, M.E. Biagini, C.Biscari, R.Boni, M.Boscolo, F.Bossi, B. Buonomo, A.Clozza, G.Delle Monache, T. Demma, E.Di Pasquale, G.Di Pirro, A.Drago, A.Gallo, A.Ghigo, S.Guiducci, C.Ligi, F.Marcellini, G.Mazzitelli, C.Milardi, F.Murtas, L.Pellegrino, M.A.Preger, L.Quintieri, P.Raimondi, R.Ricci, U. Rotundo, C.Sanelli, M.Serio, F.Sgamma, B.Spataro, A.Stecchi, A.Stella, S.Tomassini, C.Vaccarezza, M.Zobov (INFN/LNF, Frascati (Roma)), I.Koop, E.Levichev, S.Nikitin, P.Piminov, D.Shatilov, V.Smaluk (BINP SB RAS, Novosibirsk), S.Bettoni (CERN, Geneva), M.Schioppa (INFN Gruppo di Cosenza, Arcavacata di Rende (Cosenza)), Paolo Valente (INFN-Roma, Roma), Kazuhito Ohmi (KEK, Ibaraki), D. Teytelman, J. Fox (SLAC), Nicolas Arnaud, Dominique Breton, Leonid Burmistrov, Achille Stocchi, Alessandro Variola, Benoit Viaud (LAL, Orsay), Marco Esposito (Rome University La Sapienza, Roma), Eugenio Paoloni (University of Pisa and INFN, Pisa), Paolo Branchini (University Roma3, Rome) Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  3. Outline • DANE original configuration overview • New collision scheme and collider upgrade: • Large Piwinski angle and Crab-Waist • Some issues related to the DANE commissioning: • Ring optics • Bunch length and ring impedance • Beam currents • Recent Luminosity breakthrough after a careful activity aimed at improving the collider performances by: • Optics refinement • Beam dynamics studies • Subsystem developments • Conclusions Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  4. Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  5. KLOE FINUDA (DEAR) DAFNE Parameters (original configuration) Llogged (fb-1) 2001÷2007 Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  6. Luminosity [cm-2 s-1] Lpeak at DANE 2001 ÷ 2007 Lpeak had a remarkable evolution mainly due to several machine upgrades KLOE FINUDA

  7. Rationale for the Upgrade Lpeak ~ 1.6 1032 cm-2 s-1 was the maximum luminosity achievable in the original DANE configuration due to: y Overlap area @ IP • y ~ z to avoid hourglass effect • Long-range beam-beam interactions causing + - reduction limiting I+MAX I-MAX and consequently Lpeak and L∫ • Transverse size enlargements due to the beam-beam interaction y* z z A new conceptual approach was necessary to reach L~1033 Collision scheme based on Large Piwinski angle and Crab-Waist Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  8. New IR layout Lower beam  • low x,y (tune shift) • Lgeometric gain New low-section Ad hoc low-optics • Lgeometric gain • lower y • Vertical synchro-betatron resonances suppression Large Piwinski angle • Large Piwinski angle obtained by: • small sx • large  • Small y* in fact the beams overlap region  is: Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  9. Powerful Sextupoles Proper IR optics sextupole (anti)sextupole IP • Lgeometric gain • X-Y synchro-betatron and betatron resonance suppression Crab-Waist compensation Collision with large  is not a new idea ….. Crab-Waist transformation is ! (P.Raimondi et al., 2006) Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  10. DAFNE Upgrade Parameters Larger Piwinski angle Lower vertical beta Already achieved

  11. Early commissioning milestones (N0v 07 ÷ Jul 08) • Commissioning started at the end of November 2007 • Both beams stored in the first days of December • February 2008 Crab-Waist sextupoles in operation • February 11thLuminosity monitor installation • Beginning of March first L ~ 1032 cm-2 s-1 measured • March 10thSIDDHARTA installation (preliminary setup) • First half of March new transverse horizontal feedback installed in the MRe ring • May 2008 Lpeak ~ 2.2*1032 cm-2 s-1 measured. Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  12. …… after less than six months of operations Best L∫day ~ 8.0 pb-1 Best L∫1 hou = .5 pb-1 (0.44 pb-1 during the KLOE run) I- = 1.2 A I+ = 1.1 A Luminosity [1028 cm-2s-1] • ••• SIDDHARTA May 16th 2008 • (95 colliding bunches) • ••• KLOE peak luminosity • (110 colliding bunches) Peak Luminosity obtained with the new Crab-Waist collision scheme is 30% higher than the best ever measured at DANE. May 16th 2008 Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  13. Ring Optics Commissioning • Ring Optics optimization required to: • adjust the position of the low- PM QUADs • fix misalignment errors in some elements • correct transverse betatron coupling mainly by rotating the PM focusing QUADs in the IR • minimize y by correcting the global orbit and centering the beam vertical position in the arc SXTs • add 2 electromagnetic QUADs around the IP in order to meet the phase advance requirements imposed by the Crab-Waist collision scheme • establish procedure for the CW SXTs alignment in single beam operation mode in order to have x,y,  and background constant when they are switched on Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  14. Ring Optics model • Ring model matches now quite well beam measurements in terms of: • linear optics x,y,x,y,x ,x • non-linear optics energy acceptance and "x, Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  15. Vertical beam-beam Luminosity scan Design value 3.1mm July 1st 2008 Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009 x* = .2 mm y (KEK) = .3 mm y (PEP) > .4 mm

  16. Crab sextupoles parameters On June 2008 Installed 4 “large” sextupoles of the arcs Now running at Ks(m-2) = 21 Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  17. Crab Waist Works: First Experimental Evidence Crab Sextupoloes are working since the first time they have been tested Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  18. Luminosity with CRAB SEXTUPOLES ON/OFF 95 colliding bunches Luminosity [1028 cm-2 s-1] Specific Luminosity [1028 cm-2 s-1 A-2] Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  19. DANE operations (Sep ÷ Dec 2008) • August SIDDHARTA final setup installation • some components of the e+ longitudinal feedback have been substituted (delay lines, phase shifter, etc.) • I+treshold ≤ 0.8 A seemed to be due to a fast transverse horizontal instability • About the instability: • It has been observed even before the DANE upgrade but after it is more harmful • It is compatible with the e-cloud effect • In May I+treshold ~ 1.1 A • Studies aimed at sorting out other possible sources of instability: • anomalous wake field in the e+ vacuum chamber • Trapped high order mode • nothing wrong found! •Second transverse horizontal feedback implemented Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  20. Injection KCK NEW Horizontal FBK New e+ Transverse Horizontal Feedback • The damping times of the two feedbacks add up linearly • Damping time measured: • 80 ms-1 (1 FBKs tdamping~ 10 s) • 200 ms-1 (2 FBKs tdamping~ 5 s) • The power of the H FBK has been doubled e+ IP1 NEW H FBK reference pickup KCKPL101 KCKPL202 Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  21. e+ maximum beam current • 105 bunches single beam • I+tresh ~ 1.05 A 120 bunches single beam • In collision • I+tresh ~ 0.9 A • injection saturates above I+tresh • Few beam loss events at injection end cause the loss of the whole beam Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  22. Beam Dynamics Limiting factor • A real improvement in the DANE operation has been obtained by pointing out and mitigating a 50 Hz noise propagating throughout the ground system and affecting: • Some beam instrumentation (DCCT) • e+ longitudinal and transverse feedbacks • RF system • and producing: • e+ beam longitudinal instability at high current and transverse beam size blow-up • spurious phase modulation of the RF voltage at line frequencies (50 HZ and multiples), disturbances entered through the feedback system stabilizing the beam barycentric coherent oscillation mode • Under those condition : • the beams were unstable and did no longer overlap correctly • Beam -beam resonances were excited Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  23. Injection System fast switch Switch time 150 [s] --> 40 [s] Obtained executing in parallel the procedure commands • The maximum number of pulses injected in the Accumulator has been increased: • 15 --> 17 I ~ +13% in the A (measured) • Useful to speed up the injection in the Main Rings. Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  24. Best hourly integrated luminosity • L∫1 hour = 1.033 pb-1 • High rate injection regime • 105 colliding bunches • Very useful for a future KLOE run { Fast Injection Dec. 16th 2008 Fast injection is not compatible with the SIDDHARTA operations! Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  25. Llogged = 966 pb-1 (FINUDA 2006÷2007) Perspectives • Scaling the present data from the luminosity monitor: • L∫1 hour = 1.033 pb-1 • L∫day ≥ 20. pb-1 seems possible! • Assuming 80% collider uptime  L∫month~ .5 fb-1 ….. in fact a new KLOE run has been approved, the detector should roll back on next fall

  26. Recent Achievements • L∫1 hour = .79 pb-1 • Best hourly integrated luminosity compatible with the SIDDHARTA data taking • moderate injection rate regime • 105 colliding bunches Lpeak = 4.05 cm-2s-1 Dec. 5th 2008 + 150 % (FINUDA 2007)

  27. Best daily integrated luminosity • L∫day = 15. pb-1 • moderate injection rate regime • 105 colliding bunches • L∫hour = 0.62 pb-1 + 60 % FINUDA 2007 Feb. 8th 2009

  28. 1978 198 487 472 1.31E+32 1.01E+32 Intermidiate luminosity Low currents Asymmetric currents Jan. 19th 2009 Jan. 9th 2009 Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  29. DANE Luminosity versus colliding currents } NEW COLLISION SCHEME: Large Piwinski angle Crab-Waist compensation SXTs ON PW = 1.9 y = 9.0 [mm] Luminosity [1028 cm-2 s-1] } original collision scheme KLOE 2005 PW = 0.6 y = 18. [mm] KLOE 2002 PW = 0.3 y = 25. [mm] L evaluated by the BHABHA monitor in May 2008 was underestimated (~ 15%) due to the insertion of new shields which required a new evaluation of the monitor geometric acceptance. 20% L reduction at high currents because of bunch lengthening due to the ring impedance. L ∝1/σz in Large Piwinski Angle & Crab-Waist regime. Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  30. Play role in the luminosity gain Luminosity [1028 cm-2 s-1] Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  31. ... ........ Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  32. DANE present situation • However collider performances are still limited by: • e-cloud • ion trapping • RF stability, two degree peak to peak phase jitter from the klystron • e+ vertical size increase induced by the vertical feedback Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  33. Short term developments • Improve vacuum condition in order to get 110 bunches in collision • Further systems stability optimization (RF, FBKs) • Increase Crab sextupoles strenght to reduce the transverse beam size increase due to beam-beam • Further optics refinements in order to optimize: Lpeak Lintegrated Beam lifetime Background hitting the experimental detector • Install the hybrid kickers for the e- and e+ injection (under way) • Install collimators in the transfer-lines (under way) • Standard tuning Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  34. Long term developments • Further investigation about the e+ instability source • Installation of a new dedicated kicker for the second transverse horizontal feedback in a position with higher x (x = 3 [m] -> 17 [m] ) in order to increase the feedback dynamic range by a factor > 2 • Equip the second transverse horizontal feedback with two power amplifiers providing 500W output (now 250W) • Install modified wigglers to improve beam lifetimes and reduce wall plug power consumption Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  35. DANE run schedule • SIDDHARTA experiment is taking data with a good Luminosity background ratio • Run duration depends on the Lab budget and on the experiment requirements • SIDDHARTA run should be completed by the end of July 2009 • Operation for the KLOE experiment might be resumed by the end of 2009 and are presently scheduled for three years Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

  36. Conclusions • The DAFNE collider, based on a new collision scheme including Large Piwinsky angle and Crab-Waist, has been successfully commissioned and is presently delivering luminosity to the SIDDHARTA detector • Crab-Waist scheme proved to be effective in: • controlling transverse beam blow-up • Increasing luminosity, now a factor 2,5 higher than in the past • Work is in progress to reach the ultimate design luminosity goal • 5.0•1032 cm-2s-1 • Present collider limitations will be cured during the shut-down for KLOE installation Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

More Related