Mohamad-Ziad Charif - Antares

Figure 4.1: Median counting rate of OMs as function of time.30 ± 7 KHz. However the typical ANTARES single OM counting rate is 55 KHzas see in figure 4.1.From the figure 4.1 we can extract two values that can help us determine thequality of the run (section 4.1.3). These two variables are the baseline and theburst fraction. The baseline is defined as the flat part of the distribution, and forthe burst fraction it is defined as the percentage of time (during one run) where thecounting rate is higher than 1.2∗baseline.40 K → 40 Ca + e + ¯ν (4.1)40 K + e → 40 Ar ∗ + ν40 Ar ∗ → 40 Ar + γ (4.2)Another contribution to the optical background is bioluminescence[95]. Moreoverit is not constant as 40 K is, bioluminescence activity is correlated with seacurrent and varies with seasons, the peaks on figure 4.1 are due to time-averagedbioluminescence activity around ANTARES.On figure 4.2 we can see the typical counting rate (∼ 100 KHz) registeredon the OMs. The rates are usually constant but bioluminescence activity causesbursts as seen.ANTARES registers an average of 900 neutrinos per year (Figure 4.3 ). Inaddition to that if we look at figure 4.4 we can see that the number of neutrinosdetected per month on average is season dependent, the reason for this is bioactivityin the vicinity of the detector in Spring and Summer. The full 12 linesdetector has a rate of 10 atmospheric muons per second, and 5 neutrinos per day.4.1.2 TriggersAfter each data frame is collected from the detector and sent to offshore station, anumber of trigger algorithms can be applied. The most important ones are listedbellow:66