0000000000076705
AUTHOR
Tiia Monto
Underground cosmic-ray experiment EMMA
EMMA (Experiment with MultiMuon Array) is a new approach to study the composition of cosmic rays at the knee region (1 − 10 PeV). The array will measure the multiplicity and lateral distribution of the high-energy muon component of an air shower and its arrival direction on an event-by-event basis. The array operates in the Pyh¨asalmi Mine, Finland, at a depth of 75 metres (or 210 m.w.e) corresponding to the cut-off energy of approximately 50 GeV for vertical muons. The data recording with a partial array has started and preliminary results of the first test runs are presented. nonPeerReviewed
Underground multi-muon experiment EMMA
EMMA is a new experiment designed for cosmic- ray composition studies around the knee energy operating at the shallow depth underground in the Pyh¨ asalmi mine, Fin- land. The array has sufficient coverage and resolution to de- termine the multiplicity, the lateral density distribution and the arrival direction of high-energy muons on an event by event basis. Preliminary results on the muon multiplicity ex- tracted using one detector station of the array are presented.
EAS selection in the EMMA underground array
The first measurements of the Experiment with MultiMuon Array (EMMA) have been analyzed for the selection of the Extensive Air Showers (EAS). Test data were recorded with an underground muon tracking station and a satellite station separated laterally by 10 metres. Events with tracks distributed over all of the tracking detector area and even extending over to the satellite station are identified as EAS. The recorded multiplicity spectrum of the events is in general agreement with CORSIKA EAS simulation and demonstrates the array’s capability of EAS detection. peerReviewed
Efficiencies of the drift chambers in the EMMA experiment
Cosmic rays are high-energy subatomic particles which travel almost at the speed of light all over the space. The shape of the cosmic ray energy spectrum is measured experimentally, but it is not perfectly understood. The slope of the spectrum at high energies is constant up to the knee energy (about 10^15 eV) where the slope steepens. The knee has been tried to be explained by several models which aim to describe the origin and the acceleration mechanisms of the cosmic ray. The stars and the shockwaves from supernova explosions are believed to be at least a part of cosmic ray evolution. The cosmic rays were found in the early 20th century and they have been studied with several methods. Wh…