Sensitivity of YAC to measure the light-component spectrum of primary cosmic rays at the ‘knee’ energies

Abstract

Abstract.A new air-shower core-detector array (YAC : Yangbajing Air-shower Core-detector array) has been developed to measure the primary cosmic-ray composition at the "knee" energies in Tibet, China, focusing mainly on the light components. The prototype experiment (YAC-I) consisting of 16 detectors has been constructed and operated at Yangbajing (4300 m a.s.l.) in Tibet since May 2009. YAC-I is installed in the Tibet-III AS array and operates together. In this paper, we performed a Monte Carlo simulation to check the sensitivity of YAC-I+Tibet-III array to the cosmic-ray light component of cosmic rays around the knee energies, taking account of the observation conditions of actual YAC-I+Tibet-III array. The selection of light component from others was made by use of an artificial neural network (ANN). The simulation shows that the light-component spectrum estimated by our methods can well reproduce the input ones within 10% error, and there will be about 30% systematic errors mostly induced by the primary and interaction models used. It is found that the full-scale YAC and the Tibet-III array is powerful to study the cosmic-ray composition, in particular, to obtain the energy spectra of protons and helium nuclei around the knee energies.PACS numbers: 98.70. Sa, 96.50.sb, 96.50.sd

Measurement of high energy cosmic rays by the new Tibet hybrid experiment

“…For the primary cosmic rays, we examined three primary composition models (shown in Fig.2), namely, "He-poor", "He-rich" and "Gaisserfit" models, in order to evaluate the systematic errors attributable to primary composition models [6,7]. The proton spectra of the former two models are fitted to the direct measurements at low energies and consistent with the spectrum obtained from the Tibet-EC experiment at higher energies.…”

“…Measurement of high energy cosmic rays by the new Tibet hybrid experiment J. Huang Figure 2: Primary cosmic-ray composition for He-poor, He-rich and Gaisser-fit models compared with those of direct measurements [7] and the sum of all components compared with the results obtained by the Tibet-III experiment [1] .…”

“…Another important improvement of YAC is its ability to count the number of shower particles passing through each detector to a wide dynamic range of 1 to 10 6 particles, making it possible to observe the primary cosmic rays in the energy range from ∼10 TeV to ∼10 PeV. Its goals are to reconstruct the primary energy and composition of cosmic rays at the energies between 50 TeV to 10 16 eV thereby allowing a detailed investigation of the expected "proton knee", "helium knee" and "iron knee" [6], [7]. In this paper, a short review of the experiment will be followed by an overview on the current results on the energy spectrum and chemical composition of CRs and test of hadronic interaction models.…”

Shower reconstruction performance of the new Tibet hybrid experiment consisting of YAC-II, Tibet-III and MD arrays

“…A full Monte Carlo (MC) simulation has been carried out on the development of air showers in the atmosphere using the simulation code Corsika(version 6.204) [6] including the interaction models QGSJET01C and SIBYLL2.1. For the primary cosmic rays, we examined three primary composition models [7,8], namely, "He-poor", "He-rich" and "Gaisser-fit" models, in order to evaluate the systematic errors attributable to primary composition models. Primaries isotropically incident at the top of the atmosphere within the zenith angles from 0 to 60 degrees are injected into the atmosphere.…”

“…MC shows that this new hybrid experiment has a capability of measuring the primary energy spectrum for each of 4 mass groups of P, He, Iron and 4<A<56 at 50 TeV -10 PeV range covering the knee. For details, see the paper [7,8].…”