Ultra-high energy cosmic rays generate extensive air showers in Earth’s atmosphere. A standard approach to reconstruct the energy of an ultra-high energy cosmic rays is to sample the lateral profile ...of the particle density on the ground of the air shower with an array of surface detectors.
For cosmic rays with large inclinations, this reconstruction is based on a model of the lateral profile of the muon density observed on the ground, which is fitted to the observed muon densities in individual surface detectors. The best models for this task are derived from detailed Monte-Carlo simulations of the air shower development. We present a phenomenological parametrization scheme which allows to derive a model of the average lateral profile of the muon density directly from a fit to a set of individual Monte-Carlo simulated air showers. The model reproduces the detailed simulations with a high precision. As an example, we generate a muon density model which is valid in the energy range 10
18
eV
<
E
<
10
20
eV and the zenith angle range
60
°
<
θ
<
90
°
.
We will further demonstrate a way to speed up the simulation of such muon profiles by three orders of magnitude, if only the muons in the shower are of interest.
The reconstruction of cosmic muons is important for testing and aligning the Compact Muon Solenoid experiment (CMS). In this context the Magnet Test and Cosmic Challenge (MTCC) with its comprehensive ...cosmic data taking periods including the presence of the 4 Tesla magnetic field has been like a dress rehearsal of detector hardware and software for the upcoming startup of the CMS detector. In addition to data taking also the comparison with simulated events is a crucial part of physics analyses. With respect to these tasks a dedicated cosmic muon generator, CMSCGEN, has been developed and compared with data from MTCC. As an example results from a reconstruction study using the barrel muon system are shown, comparing data and Monte Carlo prediction at the level of single chambers up to reconstructed tracks including momentum measurements.
Test beam analysis of the first CMS drift tube muon chamber Albajar, C.; Amapane, N.; Arce, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2004, Letnik:
525, Številka:
3
Journal Article
Recenzirano
In October 2001 the first produced CMS Barrel Drift Tube (DT) Muon Chamber was tested at the CERN Gamma Irradiation Facility (GIF) using a muon beam. A Resistive Plate Chamber (RPC) was attached to ...the top of the DT chamber, and, for the first time, both detectors were operated coupled together. The performance of the DT chamber was studied for several operating conditions, and for gamma rates similar to the ones expected at LHC. In this paper we present the data analysis; the results are considered fully satisfactory.
We collect and combine all published data on the vertical atmospheric muon flux and the muon charge ratio for muon momenta above 10 GeV. At sea level the world average of the momentum spectra agrees ...with the flux calculated by Phys. Rev. D 58 (1998) 054001 within 15%. The experimental accuracy varies from 7% at 10 GeV to 13% at 1 TeV. The ratio of fluxes of positive to negative muons is found to be constant, at a value of 1.268, with relative uncertainties increasing from approximately 1% at low momenta to about 6% at 300 GeV.
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