Flow of Data Analysis

Incoming detector data is sampled in groups of 10 000 events, and then analyzed and histogrammed to provide a visual representation of many detector components. Each set of 10 000 events is called a Sample, and the first four Samples are added together to create a set of Reference histograms which provide the basis for comparison (see  Analysis Flow ). Optionally, the reference histogram can be read in from a file saved from a previous run (see Loading A Saved Reference File   ). The Reference histograms are normalized to the size of one Sample. Every Sample is compared to its Reference histogram using a Kolmogorov test administered by a CERN histogramming package called hbook. The Kolmogorov test returns the probability of shape compatibility between the histograms (using the hbook routine hdiff). A probability which is equal to one represents total compatibility (the same histograms), while a value close to zero describes incompatible (different) histograms. After calculating the Kolmogorov probability between each Sample and Reference histogram, the Sample histograms which are significantly different are saved, and the next sample is taken.