Random Pictures from the Morning Session
The morning session at NeuTel today is the last one of the conference. The first few talks have concerned the biggest neutrino telescopes in operation or construction: IceCube, Km3Net, Antares, and Pingu. Earlier posts here have covered some of these facilities, so here I will get away with just posting a few random illustrations.
The first is a picture of an optical module of Km3Net: a sphere containing many photomultiplier tubes looking in all directions. Going to small PMTs is cost-effective and increases the granularity of the detector – plus I think these are quite cool objects.
The third picture below is a more serious graph, showing the sensitivity that Pingu could have to detect tau neutrino appearance. With just months of data an observation could be in the bag!
The tau neutrino signal could be detected thanks to its characteristic distortion of the cascade distribution, and extracted by a statistical analysis. To explain in detail what the graph shows, first note that the vertical axis is the neutrino energy, and the horizontal axis is the cosine of zenith angle. The different colours indicate regions of equal figure of merit, the background-subtracted signal divided by the square root of the total number of background events. I will mention that such is not a very good estimator for a statistical significance, especially in situations of small number of events; but the speaker does indicate in the slide that 5-sigma are at easy reach.