DA F NE Upgrade Status

1. DAFNEUpgrade Status David Alesini, LNF-INFN For the DANE Upgrade and Commissioning Team (*) (*) David Alesini, Maria Enrica Biagini, Caterina Biscari, Roberto Boni, Manuela Boscolo, Fabio Bossi, Bruno Buonomo, Alberto Clozza, Giovanni Delle Monache, Theo Demma, Enrico Di Pasquale, Giampiero Di Pirro, Alessandro Drago, Alessandro Gallo, Andrea Ghigo, Susanna Guiducci, Carlo Ligi, Fabio Marcellini, Giovanni Mazzitelli, Catia Milardi, Fabrizio Murtas, Luigi Pellegrino, Miro Preger, Lina Quintieri, Pantaleo Raimondi, Ruggero Ricci, Ugo Rotundo, Claudio Sanelli, Mario Serio, Francesco Sgamma, Bruno Spataro, Alessandro Stecchi, Angelo Stella, Sandro Tomassini, Cristina Vaccarezza, Mikhail Zobov (INFN/LNF, Frascati (Roma)), Ivan Koop, Evgeny Levichev, Pavel Piminov, Dmitry Shatilov (BINP SB RAS, Novosibirsk), Victor Smaluk (BINP, Novosibirsk), Simona Bettoni (CERN, Geneva), Marco Schioppa (INFN Gruppo di Cosenza, Arcavacata di Rende (Cosenza)), Paolo Valente (INFN-Roma, Roma), Kazuhito Ohmi (KEK, Ibaraki), Nicolas Arnaud, Dominique Breton, Patrick Roudeau, Achille Stocchi, Alessandro Variola, Benoit Francis Viaud (LAL, Orsay), Marco Esposito (Rome University La Sapienza, Roma), Eugenio Paoloni (University of Pisa and INFN, Pisa), Paolo Branchini (Roma3, Rome)

2. OUTLINE • DANE UPGRADE: • New IR implementing the large Piwinsky angle and crab waist collision scheme •  New fast injection kickers • New low impedance bellows • 2) STATUS • Commissioning milestones •  Best machine performances at high current •  Fast pulsers performances • Bunch length measurements •  Open problems and strategies for machine optimization

3. FROM DANE TO DANE UPGRADE e- e+ KLOE • In case of colliders with small Piwinsky angle @ IR, the key parameter to increase the luminosity is the reduction of the y* and the increase of stored currents; • To avoid luminosity reduction because of the hourglass effect y*MINz and one has to reduce z also; •  This can intruduce problems of High Order Mode heating, coherent synchrotron radiation, RF power consumption and instabilities. Overlap area @ IP y  Other possibilities to increase the luminosity are the introduction of crab cavities (testing in KEKB) or round beams (testing in VEPP2000). y* z z

4. NEW COLLISION SCHEME(P. Raimondi, 2006) • Large Piwinski’s angle P=qz /x • Geometric luminosity gain • Very low horizontal tune shift • No parasitic collisions 2. y* comp. with overlap area (y* x /) • Geometric luminosity gain • Lower vertical tune shift • Vertical tune shift decreases with oscillation amplitude • Suppression of vertical synchro-betatron resonances 3. Crab waist transformation (realized with two sextupoles) • Geometric luminosity gain • Suppression of X-Y betatron and synchro-betatron resonances

5. BEAM PROFILES @IP AND NEW PARAMETERS DAFNE (KLOE run) DAFNE Upgrade

6. NEW IR LAYOUT (1/2)

7. NEW IR LAYOUT (2/2) Old layout splitters removed New dipoles positions New layout new vacuum chambers @ IP Crab sextupoles ~10 m

8. IP FOR SIDDHARTA EXPERIMENT IP 5.5cm • Aluminum • Window thickness 0.3 mm

9. IP LAYOUT AND LUMINOSITY MONITORS SIDDHARTA K monitor Bhabha calorimeter  monitor GEM Bhabha Monitor

10. IP LAYOUT AND LUMINOSITY MONITORS SIDDHARTA K monitor Bhabha calorimeter  monitor

11. NEW IR2 CHAMBER LAYOUT (1/2)

12. NEW IR2 CHAMBER LAYOUT (2/2) • IR2 region symmetric with respect to IR1 (Possibility to swap the machine to change IP position); • “Half Moon” chamber allows complete beam separation (no 2nd IP)

13. NEW FAST INJECTION KICKERS (1/2) IP1 e+ e-

14. NEW FAST INJECTION KICKERS (2/2) VT 60 bunches t Present pulse length ~200ns 2 striplines with tapered elliptical cross section VT Strip ceramic supports 3 bunches BEAM t • EXPECTED BENEFITS • higher maximum stored currents; • Improved stability of colliding beams during injection; • less background allowing data acquisition during injection; pulse length ~6 ns • KICKERS PECULIARITIES • The new kickers can be feed by the old pulsers (200 ns) or by the new pulsers (6 ns); • They have a beam coupling impedance and HOM content much lower with respect to the previous ones; • The design, slightly modified, can be adopted also for the ILC damping ring.

15. NEW BELLOWS OLD BELLOW • 6 new bellows for each ring; • Shielding based on Be-Cu  strips 0.2 mm thickness; • lower impedance and better mechanical performances;

16. DANE COMMISSIONING MILESTONES • Commissioning started at the end of November • Both beams stored in the first days of December • Low- optics applied in January and first collisions • First week of February solenoid winding installed in the MRp and 800 mA stored for the first time after the upgrade (special pattern) • February Crab-Waist sextupoles in operation • February 11th Luminosity Bhabha monitor installation • Beginning of March first L ~ 1032 is measured • March the 10th SIDDHARTA installation • First half of March new transverse horizontal feedback installed in the MRe ring As a consequence, the frequencies of the MR and DR RF cavities has been changed by changing the tuner operation point. Since the DR length has not been reduced a new DR optics configuration and orbit has been calculated and implemented. The new rings layout is ~10 cm shorter than the original one.

17. LINEAR OPTICS MODEL OPTIMIZATION Measured -functions and dispersion compared with the optics model • Orbits in the machine have been optimized and some elements re-aligned. • Linear optics model has been optimized comparing the measurement results (tunes, -functions, dispersion,..) with the theoretical ones. • XY coupling has been corrected by rotating the permanent quads (k=0.5% reached in both rings). • Also the permanents quadrupoles and crab sextupoles longitudinal positions have been optimized to match the crab wais conditions. • Positions of the quadrupoles in IP2 have been changed to improve the beam stay clear • (…) Ex. OF VERTICAL BEAM BEAM SCAN Very good knowledge of the machine linear model

18. EFFECTS OF CRAB SEXTUPOLES ON LUMINOSITY LUMINOMETERS A huge work on machine optimization has been done and is still in progress in term of feedbacks systems tuning, background minimization and tuning of the machine luminosity… Crab on Crab off Transverse beam dimensions at the Synchrotron Light Monitors

19. HIGH CURRENT OPERATION (1/2) Achieved 1200mA e- and 960mA e+ (single beam) • Specific Luminosity is 3÷4 times higher than during the past best runs, as expected. •  exhibit a linear behavior • Lpeak21032 Achieved 1200mA e- and 850mA e+ in collision, max simultaneous about 700mA against 700 mA

20. HIGH CURRENT OPERATION (2/2) Luminosity monitors 1 day integrated luminosity  monitors Colliding beams Not colliding beams (vertical separation) K monitor Bhabha calorimeter Geometrical luminosity monitor Within <20% all monitors gives consistent results in term of luminosity

21. TEST OF FAST PULSERS WITH NEW KICKERS 25 kV 200 ns • The new kickers can be feed by the old pulsers (200 ns) or by the new pulsers (6 ns). • First test on e+ ring with fast pulsers have been successfully done. • Unfortunately we had problems with the new fast FID pulsers after few hours of operation. They have been now recovered and ready to be re-installed. 45 kV 5 ns

22. BUNCH LENGTH MEASUREMENTS e+ e- Machine impedance reduction of about 30%

23. CONCLUSIONS, OPEN PROBLEMS AND STRATEGIES -Good operation with crab sextupoles (test of crab waist concept); -Good knowledge of the machine optics model; -Reached the coupling goal of 0.5%; -Good vacuum conditioning; -Achieved 1200 mA e- and 960 mA e+ and 1200mA e- and 850mA e+ in collision with a peak luminosity of 21032 a continuous optimization is in progress; -Bunch lengths measurements show a shorter bunch due to lower machine impedance; -Fast kickers test done with success  we need to go in continuous operation with the new pulsers; -No “hard to fix” problems found so far  a lot of “single pieces” are working very nicely, need to put all together at the same time; -Commissioning rate a factor 2 slower than hoped; -Beam lifetimes need dynamics aperture optimization -Background optimization has been done  and is further necessary for the SIDDHARTA experiment