6533b828fe1ef96bd1287aa8
RESEARCH PRODUCT
Can EMMA solve the puzzle of the knee?
H. O. U. FynboJari JoutsenvaaraKai LooBayarto LubsandorzhievJ. SarkamoT. S. RäihäJ. KarjalainenA. VirkajärviPeter M. JonesT. KalliokoskiWladyslaw Henryk TrzaskaTimo EnqvistL. B. BezrukovL. V. InzhechikV. PetkovMaciej SlupeckiPasi Kuusiniemisubject
PhysicsNuclear and High Energy PhysicsHigh energyMuonPhysics::Instrumentation and DetectorsAstrophysics::High Energy Astrophysical PhenomenaAstrophysics::Instrumentation and Methods for AstrophysicsCosmic rayKnee regionWater equivalentSpectral lineNuclear physicsOverburdenIndependent datadescription
Abstract The knee is a change in the slope of the cosmic ray spectrum at approximate energy of 3 PeV. There are multiple competing models for the knee giving conflicting predictions about this change for different masses of the primary particle. Accurate mass measurements of cosmic rays spectra around 3 PeV would be able to exclude some of these models. Cosmic-ray experiment EMMA uses a new method for studying the composition of cosmic rays at the knee area. It is able to determine the multiplicity, the lateral distribution, and the arrival direction of incoming muons produced early in the shower evolution on an event-by-event basis and deduce from these measurements the mass and the energy of the primary particle. EMMA is situated at the depth of 75 m in the Pyhasalmi mine, Finland. This rock overburden, which corresponds to 210 m of water equivalent, gives EMMA a cut-off energy of 50 GeV for vertical muons. Since the simulations using different air-shower models give similar predictions for the lateral distribution of these high energy muons, we are confident that EMMA should yield a reliable and an air-shower model independent data on the composition of cosmic rays around the knee region.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2011-04-01 |