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. DAFNE Parameters (original configuration) Llogged (fb-1) 2001÷2007
FINUDA (DEAR)
KLOE
Energy (GeV)
0.51
Circumference, m
97.69
RF Frequency (MHz)
368.26
Harmonic Number
120
Damping Time (ms)
17.8/36.0
Bunch Length (cm)
1-3
Emittance (mm mrad)
0.34
Coupling %
x/y Function at IP (m)
1.7/0.017 (KLOE)
2.0/0.019 (FINUDA)
Max. Tune Shifts (nominal)
Number of Bunches
100÷111
Max.Beam Cur. I-/I+ (A)
2.4/1.4 (KLOE)
1.5/1.1 (FINUDA)
Llogged (fb-1) 2001÷2007
DEAR
0.2
KLOE
3.0
FINUDA
1.2
Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

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

7. Rationale for the Upgrade
Lpeak ~ cm-2 s-1 was the maximum luminosity achievable in the original DANE configuration due to: y
Overlap 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. Large Piwinski angle Large Piwinski angle obtained by: small sx
Small y* in fact the beams overlap region  is:
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
Catia Milardi SuperB Workshop, LAL (Orsay), February 15-18, 2009

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

10. DAFNE Upgrade Parameters
FINUDA
DAFNE Upgrade
qcross/2 (mrad)
12.5 25
ex (mmxmrad)
0.34
0.26
bx* (cm)
170 26
sx* (mm)
0.76
FPiwinski
1.9
by* (cm)
1.70
0.90
sy* (mm)
5.4 (low current)
3.1
Coupling, %
0.5
Ibunch (mA) 13
sz (mm) 22 20
Nbunch
110
L (cm-2s-1) x1032
1.6 5
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 11th Luminosity monitor installation
Beginning of March first L ~ 1032 cm-2 s-1 measured
March 10th SIDDHARTA 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. May 16th 2008 …… 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
 (mrad) 25
y*(mm) 10
x*(mm)
250
ysext(m)
13.5
xsext(m)
4.2
Ks (m-2) 36
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. NEW H FBK reference pickup
New e+ Transverse Horizontal Feedback
The damping times of the two feedbacks add up linearly
Damping time measured:
80 ms (1 FBKs tdamping~ 10 s)
200 ms-1 (2 FBKs tdamping~ 5 s)
The power of the H FBK has been doubled
Injection KCK
NEW Horizontal FBK 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 --> 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. L∫day ≥ 20. pb-1 seems possible!
Perspectives
Scaling the present data from the luminosity monitor:
L∫1 hour = 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
Llogged = 966 pb-1 (FINUDA 2006÷2007)

26. Recent Achievements Lpeak = 4.05 cm-2s-1 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. 1.01E+32 1.31E+32 Intermidiate luminosity Low currents
487
472
1.01E+32
Low currents
Asymmetric currents
Jan. 19th 2009
1978
198
1.31E+32
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 = 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/σ z 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
DANE upgrade
SIDDHARTA
DANE
KLOE
DANE FINUDA
Lpeak [cm-2s-1]
4.05• (5.0•1032)
1.5•1032
1.6 •1032
L∫day [pb-1]
14.98
9.8
9.4
L∫1 hour [pb-1]
1.033
0.44
0.5
I-MAX in collision [A]
1.4
1.5
I+MAX in collision [A]
1.1
1.2
Nbunches
105
111
106
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