1. 44 th LNF Scientific Committee, Frascati, 4-5 June 2012 DA  NE Status Catia Milardi (on behalf of the DA  NE Team)

2. OUTLINE Luminosity results & Background Collider uptime technical faults consolidation activities Ring optics developments Beam Dynamics Man power Future Plans Conclusions

3. DA  NE upgrade SIDDHARTA (2009) DA  NE KLOE (2005) L peak [cm -2 s -1 ]4.5310 32 (5.010 32 )1.5010 32 L ∫day [pb -1 ]14.989.8 L ∫1 hour [pb -1 ]1.0330.44 I - MAX in collision [A]1.521.4 I + MAX in collision [A]1.01.2 N bunches 105111 yy 0.0440.025 Maximum Peak Luminosity so far … Same peak luminosity as in 2005, but less bunches in collision (100) lower currents

4. Luminosity [10 28 cm -2 s -1 ] Comparison among DA  NE best runs with and without Crab-Waist At low currents the highest L s achieved exceeds by 2÷3 times the best value measured during the past KLOE runs

5. Best hourly integrated luminosity L ∫1 hour = 0.359 pb -1 L ∫day = 8.62 pb -1

6. Sunday, May 6 th 2012 ~ 80% uptime Best day L ∫day ~ 7 pb -1

7. Luminosity History

8. DA  NE operations Since January 2012 DA  NE operations suffered for several problems: Hardware faults Cooling system Power supplies Control system Injection kickers Linac klystron discharge Anti-solenoid power supply Holes in the Wiggler coils Beam pipe heating at IP1 Non reproducibility of the beam parameters in the Main Rings Slow drift of the beam trajectory in the Transfer Lines Radioprotection alarm in the Control Room Adverse meteorological conditions: DA  NE activities stopped for 6 and half days in February Several glitches in the electric network

9. DA  NE fault occurrency

10. Bellows degassed, e - KCK feed through replaced, water leakage MRs,  H2O restoredHole in the WGLEL101 coil,  H2O restored Solenoid power supply faultEntrance end pole of the WGLEL101 is first soldered than replaced Snow, glitches in the electric network, water leakage MRs, Exit end pole of the WGLEL101 replaced, severe water leakage from the fluid system main duct,  H2O restored Holes in the WGLEL101, WGLES101, water leakage from the WGLES201 spigots,  H2O restored Anti-solenoid power supply fault in the MRpControl system fault due to the CPU controlling the KCKs in the MRpControl system fault due to the CPUs controlling the KCKs in the MRsLongitudinal measurement of the KlOE IRMicroswitch of the scrapers replaced2 new dc generator for the ICE installed Alignment measurements in TLe Radioprotection measurements in the MRs hall, lead shields installationRadioprotection measurements in the MRs Jan – March 2012 problems with the injection, radioprotection alarm, vacuum rise in MRe Jan – May 2012 supervisor of the Cooling System not running, power supply, KCKs faults

11. DA  NE uptime

12. On mid January a sudden rise occurred in the temperature of the beam pipes inside the KLOE detector due to the leak of electrical continuity in the bellows at both ends of the section common to the two beams. Temperature Celsius degrees BEFOREAFTER Restoring electrical continuity Electrical continuity in the IR

13. Vacuum spikes in the MRe Spikes in the vacuum pressure are observed, close by the first injection kicker, when storing the beam after a stop. The bellows after the feedthroughs of the injection kicker, in the electron ring, have been all replaced (Jan 2012). Possible explanation: Dynamic vacuum still need to be improved Small discharge in the injection kicker

14. Wiggler faults in the Mre (March 25 th 2012) Three out of four wigglers installed in the e - ring got seriously damaged due to a long term water leakage not detected due to a concomitant fault in the power supply board supervising the ground fault occurrence. …. discharge between the coils and the vacuum chamber … calcareous concretions … holes in the coils (6 mm wide)

15. March 29 th 2012 L peak = 1.33 cm -2 s -1 L ∫1 hour = 0.324 pb -1 The Wiggler faults have been recovered in two and half days and …..

16. Main Rings optics Relying on linear optics measurements (  1,  2, 1, 2,  x,  x,  x,  y ) the Main Rings optics has been rematched (March) in order to restore: the required betatron function at the IP as well as at the CW sextupoles The proper phase advance between the injection kickers Symmetry in the short sections As a consequence of the beam rematch: smoother injection with higher efficiency and lower radiation level Reduced beam blow-up with the main and the opposite beam current

17. Luminosity comparison Before optics rematch March 2012 After optics rematch March 2012

18. Luminosity comparison December 2011 After optics rematch March 2012

19. Before optics rematch March 2012 After optics rematch March 2012 Background comparison

20. December 2011 After optics rematch March 2012

21. Clearing electrodes for e-cloud suppression Clearing electrodes are operative and produce the expected effect on the positron beam paremeters in terms of: Transvese beam size Horizontal tune-shift Horizontal instability growth rates

22. Horizontal Instability Growth Rate Measurements Using Bunch-by-Bunch Feedback Mode 0 -1 Mode = -1 is unstable Applied voltages: 0 V, 70 V and 140 V

23. DA  NE e + beam: 100 bunches, spaced by 2.7 ns with 20 buckets gap Turning some electrodes off (4 in the wigglers and 2 in the dipoles ) horizontal tune spread is almost halved Measured by using the front end of the Bunch-by-Bunch feedback systems designed to damp the coupling instabilities. OFF ON OFF ON Tune Spread Measurements Horizontal  x 1-100 ~ 0.006 (off)  x 1-100 ~ 0.003 (on)  x > ~ 0.0065 (on/off)

24. .. electrodes are effective in reducing the tune spread also in the vertical plane... OFF ON  y 1-10 ~ 0.002 (on/off)

25. Vacuum Chamber HOM Shifts: results Preliminary data analysis outlined the following points: all modes have a positive frequency shift as a function of the positron beam current. At I + ~800 mA, it is between 100 and 400 kHz depending on the modes under consideration switching on the electrodes the frequency shift can be partially cancel for almost all modes quality factor of the modes decreases with positron current; for some modes the frequency shift does not depend on the electron voltage. It might be due to the fact that those modes are localized in different places of the arc or in regions not covered by electrodes. Frequency shifts can be used to evaluate the e-cloud density (see the theory given given in [J. Sikora et al., MOPPR074, IPAC12] Identification of resonant mode location is still in progress, it is not trivial due to the complex 3D geometry of the arc chamber

26. Possible explanation??? Current supplied by the generator I  V DC  n e- e-cloud density n e-  I B -  V DC. Combining the two previous relations we obtain that I  V DC  I B -  V 2 DC, The e-cloud is completely absorbed when I  0. In all other situations there is still an e-cloud density. Fitting these curves and scaling their behaviour up to currents >1A, one discover that a voltage of the order of 250 V is no longer adequate to completely absorb the e-cloud when I B >1A. So the applied voltage has to be increased. Current delivered by voltage generators The voltage generators connected to the electrodes absorbs the photo-electrons. In the present configuration each voltage generator is connected to three electrodes of one arc (i.e. one wiggler and two dipoles). The current delivered by the generator has been measured as a function of the generator voltage and for different beam currents.

27. Bunch Length Measurements (May 2012) ---- e + May 2012 (V RF = 180 kV scrapers in) ---- e - May 2012 (V RF = 180 kV scrapers in)

28. Comparison between e - bunch length measurement ---- e - May 2012 (V RF = 180 kV scrapers in) ---- e - Jan 2011 (V RF = 180 kV scrapers in)

29. Comparison between e - (2011) and e + (2012) bunch length measurement Impedance (at least its inductive part) seems to be higher in the electron ring than in the positron one despite the e-cloud clearing electrodes ---- e - Jan 2011 (V RF = 180 kV scrapers in) ---- e + May 2012 (V RF = 180 kV scrapers in)

30. Dynamic Vacuum trend in MRp

31. Highest currents stored by now

32. DA  NE manpower Run Coordinators Involvement %Other Activities Milardi70xEU projects Zobov50xEU projects Drago60xSuperB, SPARC, EU projects Di Pirro25SPARC, ELI Mazzitelli20BTF, LNF Formation, SuperB Stella60xSuperB, SPARC Guiducci15SuperB, EU projects, ILC Boscolo25 SuperB, ELI, SPARC, LNF Tutorial Biagini15SuperB, EU projects, ILC Liuzzo20xLeaving in a week Foggetta20BTF, EU projects, SuperB GhigoDivision Leader Gallo30x SuperB, EU projects, ILC, SPARC, ELI Alesini25EU projects, SPARC, ELI Bini25SPARC, SuperB Buonomo60XBTF, EU projects Since December 2011 the DA  NE Run Coordinators decreased by 5 units.

33. AD Group Scientist (Run Coordinator) Technicians (DA  NE Operator) AD Staff1 Electronics, Controls & Diagnostics 1 + 13 + 3 Cryogenics Plant24 Magnets & Power Supplies 11 + 3 Mechanics12 + 5 Linac13 + 7 RF11 + 3 Control System12 + 2 Vacuum System13 + 4 TD Group Scientist (Run Coordinator) Technicians (DA  NE Operator) Fluid System12 + 3 Electric Plant12 + 1 DA  NE Technical support

34. DA  NE plans Jun 1 st – July 15 th machine and luminosity studies Jul 15 th – Aug 27 th shut down for ordinary maintenance Sep 3 rd – Oct 31 st machine and luminosity studies Oct 31 st shut-down for KLOE inner tracker installation and DA  NE consolidation

35. The peak luminosity is now comparable with the maximum achieved at the end of the KLOE run in 2005 Luminosity at low currents letting in collision 10 bunches is quite promising At low currents the highest L s achieved exceeds by 3 times the best value measured during the past KLOE runs Luminosity achieved in December is reproducible regardless the IR heating problem Maximum currents stored so far in collision are: I - ~ 1.3 A I + ~ 0.9 A Clearing electrodes are effective in keeping under control the e-cloud driven instabilities in the positron ring. An even better effect is expected after replacing the electrodes power supplies. The uptime of the Linac subsystem, after a careful maintenance plan is now ~ 75% DAFNE while working for the KLOE-2 experiment is also providing beam to the BTF and synchrotron radiation to the LNF beam lines Some crucial points

36. Presently DA  NE, assuming 280 days of run and 80% uptime, might provide a yearly integrated luminosity in the range 2÷2.5 fb -1 Relying on preliminary measurements and on the past experience it seems reasonable to increase the yearly integrated luminosity up to 3÷3.5 fb -1 DA  NE is a collider of unequalled complexity (compact rings with no symmetry, collision at low energy with high currents) The KLOE-2 IR is based on innovative concepts never tested before Pushing the DA  NE luminosity, in the KLOE-2 configuration, at the same levels achieved during the test of the Crab-Waist collision scheme requires a remarkable efforts and expert man power (linear and non-linear optics, beam dynamics, beam-beam interaction, mechanical engineering) The DA  NE accelerator complex is in operation from more than 13 years, as such it requires extraordinary and expensive maintenance in order to guarantee a 80% uptime Testing the Crab-Waist collision with a large detector is a relevant issue for other projects Conclusions

37. Thank you for your attention

38. SPARE SLIDES

40. Beam-beam is not a limiting factor Crab-Waist sextupoles work This result can be improved by: Vacuum conditioning Scrabbing in the MRp Optimizing multibunch and high current operations 10 consecutive bunches 10 bunches Luminosity

41. Vertical orbit oscillation Vertical orbit oscillation (updated from Scient. Comm. June2011) Typical harmonic components of the positron beam vertical oscillation Turn by turn e+/e- beam position measured at two monitors (symmetrical with respect to the IP) Beam oscillation reduction in the lower bandwidth due to activities carried on to damp residual mechanical vibration of the IP region Fixed ripples of a few corrector magnets power supply at 50Hz and 100Hz Apr11 Nov11

42. Turning off the electrodes the transverse vertical beam dimension enlarges  + y (  m)  + x (  m) However the power supplies of the clearing electrodes must be replaced cause their load impedance changes with the beam current

44. Specific Luminosity (December 2011) N1: + x = 0.1100 + y = 0.1810 nominal tunes - x = 0.0955 - y = 0.1615 N2: betratron coupling optimized N3: + x = 0.1020 + y = 0.1690 e + tunes lower  - x = 0.096 - y = 0.1605 N4: + x = 0.1020 + y = 0.1690 e + e - tunes lower  - x = 0.094 - y = 0.1560 At low currents L s exceeds by 3 times the best value measured during the past KLOE runs.