STATUS OF BEPC2002 OPERATION
Y. Chen, X. Wang, IHEP, P.O. Box 918, Beijing 100039, China
Abstract
Supported by the leaders of IHEP and accelerator
center, BEPC operation made a great achievement in2002. The total operation time was 4908 hours, in which
1729.2 hours were for high-energy physics experiments,
1425.2 hours for the synchrotron radiation application,
511.5 hours for the injection, 164.6 hours for thebreakdown, 388.2 hours for hardware maintenance andregulation, and 655.3 hours for the machine studies,
respectively. Compared with last year, the total operationtime exceeded the operation plan by 348 hours on accountof the high operation efficiency. Table 1 and Fig. 1 show
the statistics of the BEPC running in 2002.

Table 1 Statistics of BEPC performance in 2002
BES

BSRF

MD

Injection

RecoveryBreakdown

Other

Total (hour)

1729.41425.2

655.3

511.5

388.2

164.6

33.8

Percentage (%)

35.24

29.04

13.35

10.42

7.91

3.35

0.69

Recovery
7.91%

Failure
3.35%

Other
0.69%
BES
35.24%

Injection
10.42%

the new record of luminosity at ψ(2S) energy. Till Mar.
13, 2002, BES totally gained 14.62 M hadron events,
more than the scheduled task, which is 14 M ψ(2S) events.
From Apr. 23 to May 19, BES totally gained 0.2858 M-1
ψ(3770) events, the integrated luminosity was 8.15 pb ,more than the scheduled task 6~8 pb-1.

2.Operation for Synchrotron Radiation
MD
13.35%

BSRF
29.04%

Fig. 1 Statistics of BEPC performance in 2002

1.Operation for High Energy Physics
Operation for the high energy physics accounted for the35.24%, while BES operating at the resonance peak ofψ(2s), ψ(3770), the maximum current achieved 90mA.
Due to the effort of operation group, many record such as
peak luminary were broken. 14.63 million hadron casewere collected compared with the plan which was 14million. Meanwhile 350 hours was offered to the 10th
experiment hall for the BESIII design.
The 2001/2002 operation of BEPC finished on Jun.15,
2002. When supplied beam to BES at the energies ofψ(2S) and ψ(3770), BEPC operated stably and thecollision beam current increased gradually, the maximum
beam current was about 90 mA. By the hard work ofoperation people, some operation records, such as thepeak current and luminosity and the hadron events pershift, per day and per week were frequently renewed. For
example, on the night shift of Mar. 12, 2002, themaximum luminosity reach 1.258× 1031 cm-2s-1, which is

Accounting for 29.04%, 1425.2 hours were offered tosynchrotron radiation, which was the most operation time
up to now, in synchrotron mode, the maximum current
achieved 120-130mA with 20-30 hours lifetime. 293
BSRF experiment tasks were completed. On the whole,beam quality and operation efficiency were satisfied.
The 2002/2003 operation of the storage ring started on
Nov. 8, 2002. After two week commissioning of themachine, the BEPC began to provide beam to SR byoperating in a dedicated mode. During commissioning
time, the beam injected favourably, but the beam lifetime
was very short, for the worst vacuum in the storage ring
was only 3×10-8 Torr. Gradually, the beam lifetime
increased, as the vacuum became better. Two new
wiggler magnets, 1W1 and 4W2, worked normally, butmore imperceptibly adjusting on beam line and morestudies on the GAP of 4W2 were needed. The 4W1A
beam line was greatly difficult to operation, try it’s best,the. position and angle of beam at 4W1 were adjusted, but
no directed light can be observed, the beam line had to beabandoned provisionally at last.

3.Machine Studies
Total machine studies time was 655.3 hours in lastperiods, in order to ensure the operation of BES andsynchrotron, less time was used to study the machine.
As for the storage ring, the machine studies focused on
the following question, PEI experiment, BBA, RF systemthree cavity tuning and BEPC coupling measurement andso on.
As BEPC’s injector, machine studies were also
important for Linear accelerator, many results wereachieved on the energy gain research, positron beam,energy spread, buncher and pre-buncher adjustment
which was essential to keep greater beam and injection
rate, the injection rate was more than 3 mA/min on theaverage.

In 2002, the machine study was focused on thefollowing fields: 1) Studies on the photoelectron effect; 2)
Studies on the beam-based alignment system; 3) Studies
on the beam lifetime reduction in the dedicated SR
operation, i.e., observing the electron beam lifetime whenthe distributed ion pumps were switched off; 4) Studieson the dedicated SR mode; 5) Studies on the GAP of 4W2
wiggler magnet; 6) Studies on the top off injection; 7)
Measurement of the coupling in BEPC, etc.