1,721,106 research outputs found
Measurement of the proton-air inelastic cross section at root (s) approximate to 2 TeV from the EAS-TOP experiment
No full textThe proton-air inelastic cross section (σp-airinel) is measured at √s≈2 TeV at the EAS-TOP extensive air shower experiment by studying the absorption length of cosmic ray proton primaries cascades reaching the maximum development at the observation level. Primary energies, in the region E0=(1.5÷2.5)·10(15 ) eV, are selected through the EAS muon number (Nμ), and proton originated cascades at maximum development are selected by means of the shower size (Ne). The observed absorption length (λobs) is a convolution of the proton-air interaction length (λp-air) and of the shower and detector fluctuations. The conversion factor k=λobs/λint is obtained by means of simulations performed with the CORSIKA code and the QGSJET II and SIBYLL interaction models. The obtained value of the p-air inelastic cross section at √s≈2 TeV is σp-airinel=338±21(stat)±19(syst)-28(syst) mb. The statistical and systematic uncertainties, as well as the relationships with the pp (p̅ p) total cross section measurements are discussed
Temperature variations in the low stratosphere (50–200 hPa)monitored by means of the atmospheric muon flux
No full textThe dependence of the muon flux on the atmospheric parameters
(pressure and temperature) is a well-known effect since long time ago. We have correlated the muon flux recorded by the electromagnetic detector of EAS-TOP with the atmospheric temperature (up to few hPa level) monitored by the radio-soundings of the ITAV—Aeronautica Militare at Pratica di Mare (Rome). A significant effect has been observed when the muon flux is correlated with the atmospheric temperature in the region 50–200 hPa, as expected, since this is the region where the mesons of first generation are produced. The technique has been applied to two short periods of strong temperature variations in the low stratosphere, showing that the temporal pattern of the temperature is fairly well reproduced by the variations of the muon flux. The main results of this analysis are presented
The cosmic ray primary composition in the "knee" region through the EAS electromagnetic and muon measurements at EAS-TOP
No full textThe evolution of the cosmic ray primary composition in the energy range 10(6)–10(7) GeV (i.e. the ‘‘knee’’ region) is studied by means of the e.m. and muon data of the Extensive Air Shower EAS-TOP array (Campo Imperatore, National Gran Sasso Laboratories). The measurement is performed through: (a) the correlated muon number (Nl) and shower size (Ne) spectra,and (b) the evolution of the average muon numbers and their distributions as a function of the shower size. From analysis (a) the dominance of helium primaries at the knee,and therefore the possibility that the knee itself is due to a break in their energy spectrum (at EHe k = (3,5 +/0,3) 10(6) GeV) are deduced. Concerning analysis (b), the measurement accuracies allow the classification in terms of three mass groups: light (p,He), intermediate (CNO),and heavy (Fe). At primary energies E0 circa 10(6) GeV the results are consistent with the extrapolations of the data from direct experiments. In the knee region the obtained evolution of the energy spectra leads to: (i) an average steep spectrum of the light mass group (gamma(p;He )> 3,1)), (ii) a spectrum of the intermediate mass group harder than the one of the light component (gamma(CNO) circa 2,75,possibly bending at ECNO k =(6–7) 10(6 )GeV), (iii) a constant slope for the spectrum of the heavy primaries (gamma(Fe) circa 2,3–2,7) consistent with the direct measurements. In the investigated energy range,the average primary mass increases from = 1,6–1,9 at E0 circa 1,5 10(6) GeV to =2,8–3,1 at E0 circa 1,5 10(7) GeV. The result supports the standard acceleration and propagation models of galactic cosmic rays that predict rigidity dependent cut-offs for the primary spectra of the different nuclei. The uncertainties connected to the hadronic interaction model
(QGSJET in CORSIKA) used for the interpretation are discussed
The cosmic ray proton, helium and CNO fluxes in the 100 TeV energy region from TeV muons and EAS atmospheric Cherenkov light observations of MACRO and EAS-TOP
No full textThe primary cosmic ray (CR) proton, helium and CNO fluxes in the energy range 80–300 TeV are studied at the National Gran Sasso Laboratories by means of EAS-TOP (Campo Imperatore, 2005 m a.s.l.) and MACRO (deep underground, 3100 m w.e., the surface energy threshold for a muon reaching the detector being Eth l about 1,3 TeV). By using the measurements of the proton spectrum obtained from the direct experiments and hadron flux data in the atmosphere, we obtain for the relative weights of the three components at 250 TeV: Jp : JHe : JCNO = (0,20 +/- 0,08 ) : (0,58 +/- 0,19) : (0:22 +/- 0:17). This corresponds to the dominance of helium over proton primaries at 100–1000 TeV, and a possible non-negligible contribution from CNO.
The lateral distribution of Cherenkov light in Extensive Air Showers (EASs), which is related to the rate of energy
deposit of the primary in the atmosphere, is measured for a selected proton and helium primary beam, and good
agreement is found when compared with the one calculated with the CORSIKA/QGSJET simulation model
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