The machine status and operating mechanism of BEPCII CAO, Jianshe Institute of High Energy Physics, CAS April 16, 2013 The 4th Accelerator Reliability Workshop (ARW 2013)

①Introduction ②The main progress of BEPCII ③Some fault or issues we have met ④The operating mechanism of BEPCII ⑤Summary Outlines

Bird’s Eye View of BEPC Bird’s Eye View of BEPC

 Keep most of beam lines unchanged  The circumference between collider rings and SR ring must be matched. The ratio of harmonic number is 396:402. BEPCII is an upgrade project: Single-Ring BEPC =  Double-Ring BEPCII. Same tunnel One machine, two uses: collider and synchrotron light source

The construction of BEPCII was completed in May 2008, when the detector worked together with the machine. The collider has been operating for high energy physics since May, 2009, and for synchrotron radiation users since 2007.

1.December, Detector background was reduced when Qx is set about The physics people could take data near the 0.51 working point , realized the parasitic SR mode operation.  Providing beams to both BESIII and SR users simultaneously.  Beam line 1W2 and several others from bends can work when beams collide. The main progress of BEPCII

1.February 2013, lower alpha p mode was first tested at 2.18GeV, which help us made a lot of progress in the peak luminosity. 2.Last month, we got the record luminosity of 7.08×10 32 cm -2 s -1 at 1.89GeV. The main progress of BEPCII

1.BEPCII operation for BESIII in recent one year:  have taken 520pb -1 , 10.3 hundred million J / , ～ 100pb -1 R, ~1200pb -1 Y(4260) physic data.  The operation energy value of BEPCII is more than 60 points from ~1.2GeV to ~ 2.2GeV.  Now the average physic data acquiring is about 25pb -1 at E 0 =2.13GeV per day. The main progress of BEPCII

BEPCII Operation for BSRF Experiment

1.January, Profile monitor was removed from the positron ring, which excite very strong longitudinal multibunch instability. Some fault or issues we have met Here mainly introduces the issues related to the high beam current. Bunch length observation from Streak camera 1)In BER, bunch length keeps the same along the train 2)In BPR, bunch length increases along the train, the tail part almost twice of the head part =>head: 1.5cm; tail: 3cm

12/82 Small cavity Vacuum pump port Simulation and beam experiments had been done to look for the source which may cause the longitudinal oscillation. Bunch-by-bunch luminosity before and after long. feed. system used

Some fault or issues we have met Along with beam intensity growth, particularly when the beam current is higher than 700mA on colliding mode, the heating effect due to HOM appeared, with the temperature rising shows the feature of sensitive to the bunch current. Some components were damaged due to HOM Hardware failures bellows Injection Kicker

Bellow damaged downstream of R21-AMB

Injection kicker damaged

BPR Kicker problem (ceramic board broke in Mar. 2010) Normal case Bad vacuum in BPR-K

Beam experiment to determine the problem

1.July, It was found that the final focus magnet and vacuum chamber on one side of the BESIII detector was misaligned about 10mm in horizontal direction. It was re-aligned in the summer shutdown. 2.Problems to limit the beam current may be the He pressure of BER cavity that is still exist. Some fault or issues we have met

Institute of Energy Physics Institute of High Energy Physics  Comprehensive and largest fundamental research center in China  Major research fields : – Particle physics – Accelerator technology and applications – Synchrotron radiation technologies and applications

In order to meet the country demand, several projects will be built in china, such as:  CSNS (china spallation neutron source)  BAPS (Beijing Advanced Photon Source)  ADS (Accelerator Driven Subcritical system) Those projects are responsible by IHEP. With the development of those projects, the human problems have become increasingly prominent. In order to ensure the normal operation of the BEPCII, a matrix management mode had been adopted. The operating mechanism of BEPCII

We established the full time operation team for BEPCII, the organization system chart is shown as follows: The operating mechanism of BEPCII Deputy Director of IHEP Division leader of Accelerator Center Group head of Linac Group head of the Storage Ring 10 operators  Per shift are 4 persons, 3 persons work at the central control room, and other 1 work at the Linac control room.  The type of shift is 5-shift rotation, and the work time is 12 hrs per shift.

The operating mechanism of BEPCII  In addition to full-time operation team, oncall people for the device maintenance are also arranged. they come from the every system(group) of the Accelerator Center such as PS, RF, Control groups and so on.  Every year we have special seminar in order to formulate the operation plan for both of high energy physics and SR users, and maintenance plan for summer shutdown.

The operating mechanism of BEPCII  In the operational phase, one shift (every Tuesday) has been fixed as maintenance and machine study time.  Every day (Whether it is a weekend or holiday) morning in the central control room of BEPCII, we have a regular meeting to focus on the problems which have happened in last day.  Every Monday afternoon, BEPCII project committee have a meeting to summarize the operation problem of last week and discuss the operation plan of this week.  Special team set up, concentrate on solving the special problems occurred in a period of time, for example, BESIII detector dark current.

 From 2007, The BEPCII has been put into operation more than 6 years.  Every year, the BEPCII runs about 10 months including 5.5 months for high energy physics experiments, 3 months for dedicated synchrotron radiation running, about 1.5 months for start-up and machine study (MD).  Long operation period needs high reliability for equipment. Summary

 Though the big progress achieved, some problems on both physics and hardware, are still unsolved.  Hardware faults must be greatly reduced.  More machine study time is needed.  Higher beam current is the basic requirement for the further luminosity enhancement. Summary

Thanks for your attentions !