deletions | additions       diff --git a/sectionFACILITY_OPER.tex b/sectionFACILITY_OPER.tex  index 27191e7..047ea32 100644  --- a/sectionFACILITY_OPER.tex  +++ b/sectionFACILITY_OPER.tex 
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The annual beamtime calendar at BESSY II is organized in weeks of user  operation, machine development and beamline commissioning, and  shutdown. A standard week of scheduled user beam time starts Tuesday  7:00 a.m. and ends Sunday 23:00p.m.  providing 3 three  basic user operation modes. Every other Sunday two eight hour shifts are given to the PTB  (4$^{th}$ mode).  \begin{description}  \item[Multi bunch hybrid mode] comprises 299$\,$mA total  current, kept constant by permanent top-up injections.   General bunch pattern is an even filling of 300--350 bunches and a gap of about 100--50 bunches (550$\,$MHz, harmonic number 400).   In addition to this multi bunch current, up to 5 five  specific bunches are serving dedicated experiments.   The size of the gap is negotiated: the long gap (200$\,$ns) supports pulse picking with a mechanical chopper, the short gap (50$\,$ns) aims at overall stability.  \begin{itemize} 
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The integral of the electron charge losses during top-up injection, measured on a relatively long interval time (one hour), must not exceed a prefixed threshold.   This value is obtained computing the so-called top-up-lost-charge which is the difference between the injected charge, measured through a toroid installed at the end of the BTS TL and the relative current increment, measured through the ring DCCT.   If the integral of the top-up-lost-charge per hour exceeds the prefixed threshold, the {\em top-up process is inhibited for the following hour}.   The integral of the electron charge losses during top-up injection, measured on a relatively brief interval time (about 3 to 5 s) 5$\,$s)  is not within a prefixed threshold. This interlock will permit the {\em safety system to interrupt quickly the operations}  (through the inhibition of the Linac gun) if large beam losses occur along the ring.  Another safety interlock will be based on the beam lines gamma monitors.