First look at the feasability of using the VPD as an absolute luminosity monitor for the 2009 dijet cross section measurement ...

As a check, I looked at the MuDsts from the last Vernier scan taken during Run 9, 10142059. This run lasted roughly 12 min. Only two other Vernier scan run from the 200 GeV period lasted more than 10 min: run 10112036 which lasted about 19 min and run 10134048 which lasted about 12 min. For reference, the two runs which were used for the 500GeV analysis were: run 10097097 which lasted about 25 min and 10103044 which lasted about 31 min.

Figure 1: The number of times a trigger fired over the course of the run. The first x-bin is the time at the start of the run and the bins count from that time on in 1 second intervals. The top plot shows the BHT3 trigger, the second plot shows the ZDCMB trigger, the third plot shows the BBCMB trigger and the last plot shows the VPDMB trigger.

Figure 2: This plot shows the VPD-East (Red) VPD-West (Green) and VPD-East-West (Blue) rates for the period around run 10143059 as reported by the RICH Scalars (can access them via the web here). To compare the plot below with plots in figure 1, note that the x-axis for figure 1 plots starts at time 13:38:44.