Systematic studies

A method of systematic studies leading to a detection of abnormal losses has been proposed. The method uses the integrated dose measurement by the BLMs during stable beams periods, normalized to integrated luminosity. As the beam conditions during these fills were identical, small variations are awaited. Large fill-to-fill variations indicate the unexpected loss rate change and their should be investigated in order to understand loss rate variations.

Figure 2 presents such a variation analysis for high-intensity proton fills. Monitors with the largest variations are located in the Long Straight Sections. Understanding of these variations need further investigation, but they will probably not affect the running of the machine in 2011 and 2012. Details of this study can be found in [3].

Figure 2: Study of fill-to-fill variation of beam losses: a and b are the total doses normalized to the luminosity integrated during the fill. Every point depicts ratio $\rm \bf (a-b)/(a+b)$ for one monitor (and for two fills).