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<title>BEPC Storage Ring is   to commission</title>
<h1>BEPC Storage Ring is to commission</h1>
    The upgrade of Beijing Electron-Positron Collider (BEPC) started with  new 
 components design and manufacturing in  1993 and has lasted  two years.
 Now the installation is completed and the commissioning 
is expected   to begin  by the end of March.<p>
    After the two additional RF cavities  from CERN connected to BEPC in 1993 
and 1994, the total voltage of the RF cavities has risen to higher than 2.0MV. 
With the use  of a no-touch-point tuner and High Order Mode damper,  
  the 
 reliability of RF cavities has been further improved.$
    As the voltage of RF cavities increases, the length of beam bunch is 
expected to be 
shortened from 5cm to 4cm. In  order to achieve more effective results, the 
ring's  impedance must be smaller. For this purpose, 36 bellows in the orbit  
were modified and the beam impedance is expected 
to be reduced by 1.5.<p>
    To realize a low $\beta$ the insertion quadrupoles Q1 and Q2  
were moved towards the  interaction points by 0.35m and 0.45m respectively. 
Meanwhile the new luminosity monitors have replaced the old ones. The new beam 
pipe has been constructed and mounted, which will help to reduce the background  
of the spectrometer. The improvements  also involve the four static separators, 
the vacuum pump and the power supply system.<p>
    With all the measures adopted, the luminosity of BEPC is expected to 
gain by a factor of 1.5กซ2.<p>
<p>
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February 1996 BEPC News<p>