1 Initial Commissioning of BEPCII Storage Ring J.Q. Wang 10 May, Initial Commissioning of BEPCII Storage Ring J.Q. Wang 10 May, IMAC2007

2 Outline Introduction of commissioning plan Commissioning of BSR Commissioning of BER Commissioning of BPR Commissioning of Collision Progress & Problem Commissioning plan

3 Commissioning plan reported on last IMAC meeting (23 Apr., 2006) More problem on the SC magnets…

4 Backup scheme without SCQ  To commission with beam and possibly provide beam to SR users as early as possible, meantime, take full use of the time about 6 months for the modification of the valve boxes of SCQ and the following field measurement with detector solenoid as well as the field mapping of the detector solenoid itself.  A backup scheme for the IR lattice configuration will be adopted: One normal conducting dipoles (PEPII-B) and two large aperture quads are used to replace of the two superconducting IR magnets. With this backup scheme, the outer ring, the electron ring and positron ring, as well as collision can be commissioned, respectively.

5 beam orbit in IR for the backup scheme Quad Dipole

6 IR layout of the backup scheme

7 BII Storage rings

8 SR mode: outer ring (BSR) Col. mode: e+ ring (BPR) e- ring (BER) Commissioning Stage 1 ： Backup Scheme Stage 2 ： With SCQ Stage 3 ： With detector e+ e SR

9  Preparation for BSR commissioning (-06/11.12)  BSR commissioning (06/ /12.25)  BSR user operation (06/ /02.02)  Preparation for BER commissioning (07/ /02.06)  BER commissioning (07/ /02.16)  Shutdown for Spring Festival  Preparation for BPR commissioning (07/ /02.28)  BPR commissioning(07/ /03.20)  BER and BPR rings optimization (07/ /03.25)  Collision (07/ Commissioning Procedure

10 Preparation for commissioning (-06/11.12) Sept. 22 First commissioning group meeting to assign the task for membership, including the operation manual for each subsystem, the procedure of commissioning etc. Oct. 13 Check in control room: the device control and application software for storage ring and transport line, emphasis on the day 1 commissioning requirement. Oct , Device & Control debug on-line: vacuum, beam instrumentation, power supply, injection kicker system, safety interlock system and beam control. Oct. 31-Nov. 4 ， calibration of power supply of storage ring.

11 Nov. 5 to 12, 2006 Final check for starting beam commissioning –The polarity of each magnet consists with the setting from control system –All the vacuum valves open –The temperature monitor systems for vacuum chamber and the power supply cables are OK. –Safety interlock system responses properly. –Sign the checklist for each system before start beam

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13 BSR ring commissioning （ 2006 ） Nov. 12, Commissioning of beam transport line 。 Nov. 14, First turn in the ring Nov. 18, Beam stored in the ring Dec. 09, Beam energy ramp to 2.5GeV Dec. 15, Commissioning beam line with user station Dec. 18, Beam over 1.89GeV Dec. 25, SR user experiment started Dec. 27, Beam over 2.5GeV Feb. 02, 2007, First run of SR mode completed

14 Beam profile at the exit of transport line on Nov. 12 First turn on Nov s turns on Nov. 18Beam stored on Nov. 18

15 Hardware systems debug Power supply re-calibration with a larger current range; Misconnection of some corrector power supplies found and amended; Cables of the BPM’s re-calibrated; Offsets of the BPM’s were measured with beam based alignment; Some “bad” BPM’s, judged by 3-button check, were disabled.

16 Beam current increases steadily Imax>250mA (1.55&1.89GeV), 160mA(2.5GeV SR) Tuning beam line with SR station from Dec. 15 to 25 SR user experiment

17 BSR user operation （ 2006/12/25—2007/02/02 ） With beam dose increased, beam lifetime increases steadily: 1W1 ， 3W1 ， 4W1, 4W2, 1W2 beamlines put into operation after global COD correction and orbit adjustment with local bump Orbit stability better than BEPC

18 Typical beam history of SR user operation (4 times injection/day)

19 R4OOCT4:I=0 R4OOCT4:I=-1.5A Octupole was used to damp the beam oscillation at high current

20 Statistics of SR user operation User time: 504hrs ， 11 beamlines and stations open to users, 92 experiments carried out. For the first run, beam and device commissioning were still under way, the efficiency and the fault ratio relatively high. After Jan. 14, efficiency improved to 66% 。

21 Preparation for BER commissioning 1-5 Feb. –ISPB cooling water leakage fixed and repaired. –Check the cooling water system of the inner half ring. –Beam loss monitors on the inner half ring. –Power supply and polarity check –Luminosity and background detector installation –BER control OPI, standardization & ramping. 2 Feb. final check before BER beam commissioning –BPM offset on 160Q with BSR mode –Calibration of Libera BPM –Sign the checklist

22  Feb. beam injection started, for easy tuning: Betx/bety*=2.5/0.1m, vx/vy~6.77/5.81 Libera BPM system was used for first turn tuning. On axis injection was realized by properly adjusting the kicker strength and the correctors along the ring.  Feb. 7, at about 3:00am, beam stored.  Feb. 9, beam accumulation realized by adjust Q between the two injection kickers.  Beam current<10mA before Feb. 16 due to vacuum of SCC.  After warm up to 80K during spring festival, beam increases steadily. BER commissioning （ Feb. 6-16; Mar. 20-)

23 Libera BPM signal for first several turns of beam in BER

24 Beam current history for E- Vac. 5  Every week+10mA E+ ring com. from Feb. 25-Mar. 20 Warm to 80K Vac. 1 

25 Commissioning of BPR Feb preparation for commissioning –Beam instrumentation,SCC for BPR ， –Injection ， power supplies, calibration of correctors –… Feb.28- Mar. 2 transport line commissioning –Transport line problem solved (B5 screw ， PR4) Mar. 2-3 –Use BSR optimize the transport line of positron and kickers for positron injection to the ring Mar. 3, Beam commissioning started Mar. 4, Beam stored and accumulated

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27 Beam current history of E+ Steadily increase of I b to ~170mA

28 Injection rate of positron was improved significantly by joint effort of linac (RF phase) and ring (COD, kicker): e+ Inj. Rate (For BEPC, ~5min/min)

29 Orbit Correction Beam Based Alignment was used to calibrate the BPM offset, and the COD was correct by measuring the response matrix.

30 The measured Beta function consists with the lattice model using the Fudge factor of quad obtained from response matrix analysis. Mostly,  /  <  10%,  <0.005

31 Beam stored in both rings (Mar. 20-) For high luminosity collision: Betx/bety*=2.0/0.05m, vx/vy~6.54/5.59

32 Single bunch collision: 9mA*9mA Multi-bunch collision: 7*7, ~20mA/ring Luminosity monitor is being debugged Fine tuning of beam instrumentation and control software to optimize the beam parameters (coupling, tune…) is still under way to increase the collision current for single bunch and total beam currents. Collision tuning started from Mar. 26

33 yy xx e+ ring

34 Luminosity estimate from tune shift: Lum ~5-7*10 29 cm -2 s I b =5mA Luminosity from beam size: sigmaX ＝ 489um ， sigmaY ＝ 16um, Lum~ 7.8*10 29 cm -2 s Ib=5mA Higher bunch current More bunches Higher luminoisty (100mA*100mA, 10~20 bunches)

35 10mA 0.6mA Bunch length vs current was Ib=0mA, ~1.3cm; Ib=10mA, ~1.5cm

36 More progress on the commissioning --reports from each system Beam physics: BBA, COD correction, optics ( , ,  ) measurement and correction, collision tuning, bunch length and impedance measurement… Beam instrumentation: BPM, Tune, Beam loss, DCCT, SRM, BCM, feedback… Control: power supply ramp, vacuum & temperature, timing, safety interlock… RF; Vacuum; Injection…

37 Issues to be further studied BSR 1) Synchronization of power supply during energy ramping=> reduce the tune and orbit variation. 2) Some bunches are kicked out during multi-bunch injection=> cause and cure 3) Limitation & improvement on the beam lifetime 4) Orbit deviation while lattice mode scaled with energy …

38 Issues to be further studied BER 1) Fudge factors to Qs=>cause: magnetic exciting curve/ interference between magnets/ current leakage from PS? 2) Higher beam current and RF voltage=>Vacuum of the cavity: cause & cure method BPR & BER 1)Beam instabilities due to current increase: cause & cure: Turn-by-turn data record & analysis Feedback commissioning 2) For BPR, ECI not yet studied

39 Collision Fine tuning orbit, coupling at IP; Tune scan; coupling adjustment Higher single bunch current for stable collision Clear aim for optimization goal-> luminosity monitor or beam-beam tune shift ? Reproducibility of collision parameters—>IP feedback Injection Steadily high injection rate Reduce residual beam oscillation of stored beam:  Injection while collision … Issues to be further studied

40 Goal for near term -20 May Improve beam current & lum. for collision Single bunch> 5mA*5mA,  >0.02 Multi bunch: 10~20 bunches, 50~100mA/beam => Improve tuning method for high lum. 20 May-14 June BSR mode tuning, lifetime~8 15 June- 15 July SR user operation

41 Aug. SCQ installation on-line Sept. SCQ field measurement on-line Oct. Commissioning BER&BPR with SCQ Beam collision tuning with SCQ ? Goal before detector move in Mar detector move in, collision tuning Dec Lum. (1/10~1/3) cm -2 s -1 Commissioning Plan with SCQ

42 Commissioning collision before detector move in 2007/10-11 Beam injection and optimization of lattice parameter of BER&BPR with SCQ Tuning collision 2007/ /02 Optics optimization on beta functions at IP, coupling correction, orbit control at IP, Tune scan Tuning the movable mask for lower background Tuning kicker for top-off injection Beam current increase with multi-bunch, up to 300mA, beam instability observation (including ECI) and tuning the feedback system, Goal: Luminosity up to 5-10  cm -2 s -1 with sufficient low background for detector moving in. Modified on IMAC06

43 Remarks The initial commissioning of backup scheme progressed on schedule, however, detailed optimization of collision parameters have not yet completed: the tune, coupling, etc. =>Take full use of the backup scheme to develop the tools to monitor and control the beam performance. The time period for the beam commissioning with SCQ before BESIII moved in is only about 5 months, much effort should be paid to improve the current while reduce the background. The present commissioning schedule does not include any fault or mistakes of hardware system, time period to achieve the goal for each step can be longer.

44 Acknowledgement Commissioning up to now progresses smoothly, thanks to the dedicated team with everyone working hard. Dr. Fisher from SLAC joining the first days of BSR commissioning, giving helpful advices. For SCRF operation, lot of helpful advice from KEK experts, For beam commissioning and lattice analysis, SAD was transplanted from KEK and LOCO from SLAC are used. Advices and encouragement from the IMAC committee.

45 Thank you very much for your attention!

May Commission fully upgraded linac and transport lines 1998 Nov. 30 KEKB installation complete 1998 Dec. 13 HER beam first stored 1999 Jan. 14 LER beam first stored 1999 Jan. 26 First beam-beam collisions 1999 March 26 Luminosity of 1.2x10**31 （ 2 mon,1.2/1000) 1999 May BELLE installed ( 4 mon from first col.) *10^33 (1.0/10 1 year 3mon from first col.) *10^33 (2.0/10) *10^34 (design, 4 year 4 mon from first col.) Commissioning of KEKB

47 Commissioning of PEPII 1997 June HER installation complete 1997 June 16 HER beam first stored 1997 June e+ injection transport studies 1998 January LER injection (part turn) 1998 July 10 LER construction complete 1998 July 16 LER beam first stored 1998 July 23 First collisions 1998 Dec. 8 8 x10**31 luminosity （ 8/300 ） 1998 Feb x 10**32 luminosity 1999 May BABAR detector installed (10 mon after first col.) 1999 Aug. 8 x 10**32 luminosity (1/4, 13 mon after first col.) 2000 Oct. 3.3 x 10**33 (design, 2 year 3 mon after first col.)

48 Commissioning of BEPCII 2006 Oct Installation complete 2006 Nov 18 SR beam first stored 2007 Feb 9 BER beam first stored 2007 Mar 4 BPR beam first stored 2007 Mar 20 BER & BPR beam stored 2007 Mar 25 First collision 2007 ??? Luminosity (as BEPC) 2007 ??? SR mode 250mA With SCQ ??? BER beam first stored 2007 ??? BPR beam first stored 2007 ??? First collision 2007 Luminosity (as BEPC)