Performance of the ATLAS Minimum Bias Triggers in p-p Collisions at the LHC

The ATLAS experiment is collecting proton proton collisions to perform early physics measurements such as charged particle multiplicities. These measurements will constrain various phenomenological models in the LHC energy regime. Understanding the trigger efficiencies for different event types are therefore crucial to minimize any possible bias in the event selection. The ATLAS experiment uses two types of minimum bias trigger, providing a complementary detector components and trigger levels. While a hardware based first trigger level situated in the rather forward regions with 2.2 < |eta| < 3.8 has been proved to select very efficiently proton proton collisions, the Inner Detector based minimum bias trigger uses at random seed on filled bunches and central tracking detectors for the event selection. Both triggers were essential for the analysis of particle kinematic spectra. Their performance and efficiency measurements as well as studies on possible bias sources will be presented. We also highlight the evolution of these triggers in association with more complicated analyzes.