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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Reconstruction of inclined air showers detected with the Pierre Auger Observatory

Here, we describe the method devised to reconstruct inclined cosmic-ray air showers with zenith angles greater than 60° detected with the surface array of the Pierre Auger Observatory. The measured signals at the ground level are fitted to muon density distributions predicted with atmospheric cascade models to obtain the relative shower size as an overall normalization parameter. The method is evaluated using simulated showers to test its performance. The energy of the cosmic rays is calibrated using a sub-sample of events reconstructed with both the fluorescence and surface array techniques. The reconstruction method described here provides the basis of complementary analyses including an independent measurement of the energy spectrum of ultra-high energy cosmic rays using very inclined events collected by the Pierre Auger Observatory.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS2001

Application of TURBO-AE to Flutter Prediction: Aeroelastic Code Development

The TURBO-AE program has been evaluated by comparing the obtained results to cascade rig data and to prediction made from various in-house programs. A high-speed fan cascade, a turbine cascade, a turbine cascade and a fan geometry that shower flutter in torsion mode were analyzed. The steady predictions for the high-speed fan cascade showed the TURBO-AE predictions to match in-house codes. However, the predictions did not match the measured blade surface data. Other researchers also reported similar disagreement with these data set. Unsteady runs for the fan configuration were not successful using TURBO-AE .

Hoyniak, Daniel↗
NASA NTRS1985

Electromagnetic and muonic structure of showers initiated by gamma-rays and by hadrons

If photon cascades develop by the usual mechanisms, there should indeed be notable differences between the structure of showers due to photon and hadron primaries, as regards muon densities and lateral distributions of some detector signals. The muon content of showers from Cygnus X-3, observed at Kiel, cannot be understood in this way. One remedy is to postulate arbitrarily a strong hadronic interaction of photons in the TeV region. This would utterly change the nature of electromagnetic cascades, but surprisingly does not at first sight seem to be in conflict with air shower observations.

Hillas, A. M.↗
DOE OSTI2014

Determination of the cascade-curve maximum depth from the muon component on the Yakutsk EAS array

The lateral distribution of muons with a threshold E{sub µ} secθ GeV in extensive air showers with E{sub 0} ≥ 10{sup 17} eV over the period of observations on the Yakutsk array from November 2011 to June 2013 has been investigated. It follows from this distribution that the cascade-curve maximum depth X{sub m} in the energy range (1–5) × 10{sup 17} eV increases relatively rapidly, because the cosmic-ray composition changes from iron nuclei dominating at E{sub 0} ≈ 10{sup 17} eV to protons.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Mass composition studies of Ultra High Energy cosmic rays through the measurement of the Muon Production Depths at the Pierre Auger Observatory

The Pierre Auger Observatory (Auger) in Argentina studies Ultra High Energy Cosmic Rays (UHECRs) physics. The flux of cosmic rays at these energies (above 1018 eV) is very low (less than 100 particle/km2-year) and UHECR properties must be inferred from the measurements of the secondary particles that the cosmic ray primary produces in the atmosphere. These particles cascades are called Extensive Air Showers (EAS) and can be studied at ground by deploying detectors covering large areas. The EAS physics is complex, and the properties of secondary particles depend strongly on the first interaction, which takes place at an energy beyond the ones reached at accelerators. As a consequence, the analysis of UHECRs is subject to large uncertainties and hence many of their properties, in particular their composition, are still unclear. Two complementary techniques are used at Auger to detect EAS initiated by UHE- CRs: a 3000 km2 surface detector (SD) array of water Cherenkov tanks which samples particles at ground level and fluorescence detectors (FD) which collect the ultraviolet light emitted by the de-excitation of nitrogen nuclei in the atmosphere, and can operate only in clear, moonless nights. Auger is the largest cosmic rays detector ever built and it provides high-quality data together with unprecedented statistics. The main goal of this thesis is the measurement of UHECR mass composition using data from the SD of the Pierre Auger Observatory. Measuring the cosmic ray composition at the highest energies is of fundamental importance from the astrophysical point of view, since it could discriminate between different scenarios of origin and propagation of cosmic rays. Moreover, mass composition studies are of utmost importance for particle physics. As a matter of fact, knowing the composition helps in exploring the hadronic interactions at ultra-high energies, inaccessible to present accelerator experiments.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1985

Muon fluctuation studies of EAS 10(17) eV

Fluctuation studies need to compare a parameter which is sensitive to longitudinal fluctuations against a parameter which is insensitive. Cascade calculations indicate that the shower size parameter at Haverah Park, rho (500), and the muon density are insensitive while parameters that significantly reflect the longitudinal development of a particular extensive air shower (EAS) include the muon/water Cerenkov response ratio and the muon arrival time dispersion. This paper presents conclusions based on muon fluctuation studies of EAS measured between 1976 and 1981 at Haverah Park.

Blake, P. R.↗
DOE OSTI2020

Reconstruction of events recorded with the surface detector of the Pierre Auger Observatory

Cosmic rays arriving at Earth collide with the upper parts of the atmosphere, thereby inducing extensive air showers. When secondary particles from the cascade arrive at the ground, they are measured by surface detector arrays. We describe the methods applied to the measurements of the surface detector of the Pierre Auger Observatory to reconstruct events with zenith angles less than $60^\circ$ using the timing and signal information recorded using the water-Cherenkov detector stations. In addition, we assess the accuracy of these methods in reconstructing the arrival directions of the primary cosmic ray particles and the sizes of the induced showers.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1975

Calculation of the radio emission from EAS

Time-varying features of an electron-photon cascade are considered, particularly those associated with radio emission. The cosmic ray shower is represented as a superposition of collinear 10 GeV electron-photon cascades launched at different heights in the atmosphere. Actual simulations are performed for only 10 cascades at each of 40 heights and the results are scaled to represent the total number of cascades required. The apparent angular motions of the cascade particles as detected by antennas located at various positions up to 300 m from the shower axis are simulated. The radio pulse waveform and the corresponding frequency spectrum are obtained from these motions.

Allan, H. R.↗
NASA NTRS1985

Observation of cosmic ray positrons from 5 to 25 GeV

The positron data gathered in conjunction with electron data published elsewhere is reported. The basic recognition scheme was to look for low mass positive particles that cause a cascade in a 7 radiation length shower counter. The mass criteria is imposed by selecting particles that were accompanied by Cherenkov light but whose rigidity was below the proton Cherenkov threshold. Thus the proton Cherenkov threshold represents an upper limit to the range of the experiment.

Golden, R. L.↗
NASA NTRS1985

Search for anomalous C-jets in Chacaltaya emulsion chamber experiment

Anomalous C-jets were measured in Chacaltaya emulsion chamber No.17. Measurement of 150 C-jets nuclear interactions occured in the target layer in the chamber itself with total visible energy greater than 5 TeV was completed. they are recorded in area of 11 sq m, corresponding to 17.1 sq m year exposure. Among them, seven events have no pinaught and two events are peculiar in that three showers out of four show abnormal cascade development. Two show remarkable characteristics indicating that they are coming from exotic interactions in the target layer. Illustrations of these events are presented and the thresholds of this type of event are discussed.

Kumano, H.↗
NASA NTRS1976

Phenomenological model of nuclear primary air showers

The development of proton primary air showers is described in terms of a model based on a hadron core plus an electromagnetic cascade. The muon component is neglected. The model uses three parameters: a rate at which hadron core energy is converted into electromagnetic cascade energy and a two-parameter sea-level shower-age function. By assuming an interaction length for the primary nucleus, the model is extended to nuclear primaries. Both models are applied over the energy range from 10 to the 13th power to 10 to the 21st power eV. Both models describe the size and age structure (neglecting muons) from a depth of 342 to 2052 g/sq cm.

Tompkins, D. R., Jr.↗
DOE OSTI2018

Observation of multiple-muon seasonal variations in the NOνA Near Detector

The interaction of a cosmic ray particle with an element of the atmosphere results in a cascade of particles, known as extensive air showers, which can be divided into three main branches, known as the hadronic, the electromagnetic, and the muonic component. As for the latter, since muons can reach high depths underground, they are generally used to study cosmic rays at different underground depths. The dynamics of extensive air showers is directly connected to the density of the atmosphere, as it defines the probability of particles to decay or interact. As muons are mainly produced from the decay of pions and kaons, and a warmer atmosphere results in higher number of meson decays, such particles are prone to suffer a seasonality effect that is directly correlated to the yearly seasonal variations of the atmosphere, an effect that has been verified by a large number of experiments over the past six decades. In 2015 the MINOS experiment presented an anti-correlation between the effective temperature of the atmosphere and the seasonality of the muon flux for multiplicities higher than one (i.e. more than one muon track per cosmic ray event). Said anti-correlation is not yet fully understood, counting with only a qualitative hypothesis as a probable mechanism. As such, the main goals of this study are to verify the MINOS anti-correlation effect and extend the study to verify the seasonality of the effect as a function of different variables in order to improve the understanding of the phenomenon and possible corroborations with the known hypothesis. Two full years of the NO$\nu$A Near Detector, ranging from April 2015 to April 2017, were used as the dataset for the analysis. The anti-correlation between the multiple muon flux and the effective temperature of the atmosphere is confirmed by the NO$\nu$A Near Detector, being in full agreement with the results presented by the MINOS Collaboration. The seasonal effect is also broken down by different variables: i) track separation, ii) zenith angle, iii) track angular separation, and iv) multiplicity. Different regions of these variables represent different energy ranges for the detected underground muons, their hadron parents or the primary particles that originated the cosmic ray shower, being a way to verify any particular dependency with energy. The results show that there are no clear trends in any of the studied variables, except for the multiplicity, in which the intensity of the seasonal variation increases for higher multiplicities.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Momentum Spectrum of Cosmic Muons at a Depth of 320 Mwe

Since their discovery, great progress has been achieved in the field of cosmic ray physics particularly towards the understanding of the origin, transport and acceleration mechanisms of the high energy particles that constitute primary cosmic rays, their interaction processes in the galactic and extra galactic media, and also in the Earth's atmosphere. The interaction of primary cosmic ray particles in the Earth's atmosphere leads to the production of a cascade of secondary particles or Extensive Air Showers (EAS) with various components - electromagnetic, hadronic, muon and neutrino components. There is a large number of models to describe these interactions. Many cosmic ray experiments have used a variety of observables in EAS that provide an understanding of the hadronic interactions and also shed some light on the chemical composition of the primary particles. The muon flux at the surface provides a useful tool for the calculations of neutrino fluxes, the reconstruction of EAS and it can serve as a test of various interaction models. The CosmoALEPH detector, whichwas one of the experiments in CosmoLEP used the ALEPH detector at the European Laboratory for Particle Physics, CERN, to measure the muonic component of EAS. Preliminary results have recently shown that the momentum spectrum and charge ratio for cosmic muons measured by CosmoALEPH are well within the world average. This work reports on further improvements in the reconstruction of the cosmic muon events and data analysis. Cosmic muons are produced through interactions of primary cosmic radiation in the atmosphere. They are a component of extensive air showers which can also be measured underground. The CosmoALEPH experiment used the ALEPH detector at the European Laboratory for Particle Physics, CERN, to measure cosmic muon events at a depth of 320 mwe underground. The momentum spectrum and charge ratio of the cosmic muons are measured. The results are compared with the expectations from MC simulations based on different hadronic interaction models.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Detection of a particle shower at the Glashow resonance with IceCube

The Glashow resonance describes the resonant formation of a W - boson during the interaction of a high-energy electron antineutrino with an electron, peaking at an antineutrino energy of 6.3 petaelectronvolts (PeV) in the rest frame of the electron. Whereas this energy scale is out of reach for currently operating and future planned particle accelerators, natural astrophysical phenomena are expected to produce antineutrinos with energies beyond the PeV scale. Here we report the detection by the IceCube neutrino observatory of a cascade of high-energy particles (a particle shower) consistent with being created at the Glashow resonance. A shower with an energy of 6.05 ± 0.72 PeV (determined from Cherenkov radiation in the Antarctic Ice Sheet) was measured. Features consistent with the production of secondary muons in the particle shower indicate the hadronic decay of a resonant W - boson, confirm that the source is astrophysical and provide improved directional localization. The evidence of the Glashow resonance suggests the presence of electron antineutrinos in the astrophysical flux, while also providing further validation of the standard model of particle physics. Its unique signature indicates a method of distinguishing neutrinos from antineutrinos, thus providing a way to identify astronomical accelerators that produce neutrinos via hadronuclear or photohadronic interactions, with or without strong magnetic fields. As such, knowledge of both the flavour (that is, electron, muon or tau neutrinos) and charge (neutrino or antineutrino) will facilitate the advancement of neutrino astronomy.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Dark fluxes from electromagnetic cascades

We study dark sector production in electromagnetic (EM) cascades. This problem requires accurate simulations of Standard Model (SM) and dark sector processes, both of which impact angular and energy distributions of emitted particles that ultimately determine flux predictions in a downstream detector. We describe the minimal set of QED processes which must be included to faithfully reproduce a SM cascade, and identify a universal algorithm to generate a dark sector flux given a Monte-Carlo simulation of a SM shower. We provide a new tool, "Image missing", which simulates EM cascades with associated dark vector production, and compare it against existing literature and “off the shelf” tools. The signal predictions at downstream detectors can strongly depend on the nontrivial interplay (and modelling) of SM and dark sector processes, in particular multiple Coulomb scattering and positron annihilation. We comment on potential impacts of these effects for realistic experimental setups.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1985

Penetrative nature of high energy showers observed in Chacaltaya emulsion chamber

About 30% of single core showers with E (sup gamma) 10 TeV have stronger penetrating power than that expected from electromagnetic showers (e,gamma). On the other hand, their starting points of cascades in the chamber are found to be as shallow as those of (e,gamma) components. It is suggested that those showers are very collimated bundles of hadron and (e,gamma) component. Otherwise, it is assumed that the collision mean free path of those showers in the chamber is shorter than that of hadron with geometrical value.

Funayama, Y.↗
DOE OSTI2013

Exploring ν{sub τ}−ν{sub s} mixing with cascade events in DeepCore

The atmospheric neutrino data collected by the IceCube experiment and its low-energy extension DeepCore provide a unique opportunity to probe the neutrino sector of the Standard Model. In the low energy range the experiment have observed neutrino oscillations, and the high energy data are especially sensitive to signatures of new physics in the neutrino sector. In this context, we previously demonstrated the unmatched potential of the experiment to reveal the existence of light sterile neutrinos. The studies are routinely performed in the simplest 3+1 model concentrating on disappearance of muon neutrinos of TeV energy as a result of their mixing with a sterile neutrino. We here extend this analysis to include cascade events that are secondary electromagnetic and hadronic showers produced by neutrinos of all flavors. We find that it is possible to probe the complete parameter space of 3+1 model, including the poorly constrained mixing of the sterile neutrino to tau neutrinos. We show that ν{sub τ}−ν{sub s} mixing results into a unique signature in the data that will allow IceCube to obtain constraints well below the current upper limits.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1985

LPM effect and primary energy estimations

The distortion of the electron cascade development under LPM effects is now admitted; it consists of an increase of depth of showers origin, of shower maximum T sum max, a decrease of the number of particles at maximum N sub max and results in a flattening and a widening of the cascade transition curve. Connected with the influence of multiple Coulomb scattering on basic electromagnetic processes (bremsstrahlung, pair production), this effect appears at high energy with a threshold dependent on the density of the medium (more than 10 TeV for lead, more than 10 sup 6 TeV in air). Consequently, the electromagnetic components of hadron induced showers in lead and EAS in air calculated for the same hadronic cascades in the different alternative, including or not the LPM effect are examined here.

Bourdeau, M. F.↗