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1
Brobeck, Elina Stone Edward McKeown R. D. "Measurement of ultra-high energy cosmic rays with CHICOS /". Diss., Pasadena, Calif. : California Institute of Technology, 2009. http://resolver.caltech.edu/CaltechETD:etd-10192008-143041.
Testo completo
2
Moats, Anne Rosalie Myers. "LEAP: A balloon-borne search for low energy cosmic ray antiprotons". Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184723.
Testo completoAbstract (sommario):
The LEAP (Low-Energy Antiproton) experiment is a search for cosmic-ray antiprotons in the 120 MeV to 1.2 GeV kinetic energy range. The motivation for this project was the result announced by Buffington et al. (1981) that indicated an anomalously high antiproton flux below 300 MeV; this result has compelled theorists to propose sources of primary antiprotons above the small secondary antiproton flux produced by high energy cosmic-ray collisions with nuclei in the interstellar medium. LEAP consisted of the NMSU magnet spectrometer, a time-of-flight system designed at Goddard Space Flight Center, two scintillation detectors, and a Cherenkov counter designed and built at the University of Arizona. Analysis of flight data performed by the high-energy astrophysics group at Goddard Space Flight Center revealed no antiproton candidates found in the 120 MeV to 360 MeV range; 3 possible antiproton candidate events were found in the 500 MeV to 1.2 GeV range in an analysis done here at the University of Arizona. However, since it will be necessary to sharpen the calibration on all of the LEAP systems in order to positively identify these events as antiprotons, only an upper limit has been determined at present. Thus, combining the analyses performed at the University of Arizona and Goddard Space Flight Center, 90% confidence upper limits of 3.5 x 10⁻⁵ in the 120 MeV to 360 MeV range and 2.3 x 10⁻⁴ in the 500 MeV to 1.2 GeV range for the antiproton/proton ratio is indicated by the LEAP results. LEAP disagrees sharply with the results of the Buffington group, indicating a low antiproton flux at these energies. Thus, a purely secondary antiproton flux may be adequate at low energies.
3
吳本韓 e Pun-hon Ng. "Measurement of PeV cosmic rays extensive air showers at mountain altitude". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1993. http://hub.hku.hk/bib/B31233156.
Testo completo
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Ng, Pun-hon. "Measurement of PeV cosmic rays extensive air showers at mountain altitude /". [Hong Kong : University of Hong Kong], 1993. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13781431.
Testo completo
5
Behlmann, Matthew Daniel. "Measurement of helium isotopic composition in cosmic rays with AMS-02". Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/115695.
Testo completoAbstract (sommario):
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 137-145).
The isotopic composition of helium in cosmic ray fluxes provides valuable information about cosmic ray propagation through the Galaxy, which is of particular interest to indirect dark matter searches. Helium-3, mainly a secondary cosmic ray species, is primarily produced by spallation of heavier cosmic rays, such as primary helium-4, with interstellar matter. In six years of data taking, AMS has collected the largest available data set on fluxes of cosmic-ray helium. Events are selected to form a clean sample of galactic helium nuclei, for which velocity and rigidity give a measurement of particle mass that allows the measurement of relative isotope abundances. The resolution of measured mass is described in detail by template functions based on the underlying resolutions of the silicon tracker and ring-imaging Cerenkov detector measurements. This thesis presents a measurement of the cosmic ray helium isotope ratio 3 He/ 4He in the range 0.8-10 GeV/nucleon, as obtained through a template fitting approach on AMS data.
by Matthew Daniel Behlmann.
Ph. D.
6
Fleischhack, Henrike. "Measurement of the iron spectrum in cosmic rays with the VERITAS experiment". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2017. http://dx.doi.org/10.18452/17691.
Testo completoAbstract (sommario):
Das Energiespektrum der kosmischen Strahlung bietet wichtige Hinweise auf ihren Ursprung und ihre Ausbreitung. Verschiedene Messtechniken müssen kombiniert werden, um den ganzen Energiebereich abdecken zu können: Direkte Messungen mit Teilchendetektoren bei niedrigen Energien sowie indirekte Messungen von Luftschauern bei hohen Energien. Dazu kommt die Messung von Photonen, hauptsächlich im GeV- und TeV-Bereich, die bei der Wechselwirkung von kosmischer Strahlung mit Materie oder elektromagnetischen Feldern entstehen. Im Folgenden werde ich zwei Studien dazu vorstellen, die beide auf Daten des abbildenden Tscherenkow-Teleskopes VERITAS beruhen. Erstens stelle ich eine Messung das Energiespektrums von Eisenkernen in der kosmischen Strahlung vor. Für die Bestimmung der Energie und Ankunftsrichtung der Primärteilchen benutze ich eine neuartige Template-Likelihood-Methode, die hier erstmals auf Eisenschauer angewendet wird. Zur Identifizierung der Eisenschauer benutze ich unter anderem das sogenannte direkte Tscherenkow-Licht, welches von geladenen Teilchen vor der ersten Wechselwirkung ausgestrahlt wird. Dazu kommt eine multivariate Klassifizierungsmethode, um den Verbleibenden Untergrund zu charakterisieren. Das so gemessene Energiespektrum von Eisen wird im Bereich von 20 TeV bis 500 TeV gut durch ein Potenzgesetz beschrieben. Zweitens beschreibe ich eine Suche nach Gammastrahlung oberhalb von 100 GeV von den drei Galaxien Arp 220, IRAS 17208-0014 und IC 342. Diese drei Galaxien haben hohe Sternentstehungsraten und daher viele Supernova-Überreste, welche kosmische Strahlung erzeugen. Diese wechselwirkt erwartungshalber mit den dichten Staubwolken in den Sternentstehungsgebieten und erzeugt Gammastrahlung. VERITAS konnte keine solche Gammastrahlung messen. Die daraus abgeleitete Höchstgrenze für die Luminosität schränkt theoretische Modelle der Erzeugung und Propagation von kosmischer Strahlung in der Galaxie Arp 220 ein.The energy spectrum of cosmic rays can provide important clues as to their origin and propagation. Different experimental techniques have to be combined to cover the full energy range: Direct detection experiments at lower energies and indirect detection via air showers at higher energies. In addition to detecting cosmic rays at Earth, we can also study them via the electromagnetic radiation, in particular gamma rays, that they emit in interactions with gas, dust, and electromagnetic fields near the acceleration regions or in interstellar space. In the following I will present two studies, both using data taken by the imaging air Cherenkov telescope (IACT) VERITAS. First, I present a measurement of the cosmic ray iron energy spectrum. I use a novel template likelihood method to reconstruct the primary energy and arrival direction, which is for the first time adapted for the use with iron-induced showers. I further use the presence of direct Cherenkov light emitted by charged primary particles before the first interaction to identify iron-induced showers, and a multi-variate classifier to measure the remaining background contribution. The energy spectrum of iron nuclei is well described by a power law in the energy range of 20 to 500 TeV. Second, I present a search for gamma-ray emission above 100 GeV from the three star-forming galaxies Arp 220, IRAS 17208-0014, and IC342. Galaxies with high star formation rates contain many young and middle-aged supernova remnants, which accelerate cosmic rays. These cosmic rays are expected to interact with the dense interstellar medium in the star-forming regions to emit gamma-ray photons up to very high energies. No gamma-ray emission is detected from the studied objects and the resulting limits begin to constrain theoretical models of the cosmic ray acceleration and propagation in Arp 220.
7
Vasilas, Dragoş. "Measurement of light isotopes ratios in the cosmic rays with the IMAX balloon experiment". [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972319077.
Testo completo
8
Sun, Wei Ph D. Massachusetts Institute of Technology. "Precision measurement of the boron to carbon ratio in cosmic rays with AMS-02". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99244.
Testo completoAbstract (sommario):
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 163-170).
A precision measurement of the Boron to Carbon ratio in cosmic rays is carried out in the range 1 GeV/n to 670 GeV/n using the first 30 months of flight data of AMS-02 located on the International Space Station. Above 20 GeV/n, it is the first accurate measurement. About 5 million clean Boron and Carbon nuclei are identified. The experimental and analysis challenges in achieving a high precision measurement are addressed. Boron is exclusively produced as a secondary particle by spallation from primary elements like Carbon in collisions with interstellar medium. The unprecedented precision and energy range of this measurement deepen the knowledge of cosmic ray propagation. Using this measurement, the diffusion coefficient in Gal-Prop model is determined to be (6.05 ± 0.05)10 28 cm2/s, and the Alfven velocity is (33.9 ± 1.0) km/s. This makes the prediction of secondary anti-proton background in dark matter search one order of magnitude more accurate.
by Wei Sun.
Ph. D.
9
Jia, Yi Ph D. Massachusetts Institute of Technology. "Measurement of secondary cosmic rays lithium, beryllium, and boron by the alpha magnetic spectrometer". Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119902.
Testo completoAbstract (sommario):
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2018.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 113-122).
Secondary cosmic rays are mainly produced by the collisions of nuclei with the interstellar medium. The precise knowledge of secondary cosmic rays is important to understand the origin and propagation of cosmic rays in the Galaxy. In this thesis, my work on the precision measurement of secondary cosmic rays Li, Be, and B in the rigidity (momentum/charge) range 1.9 GV to 3.3 TV with a total of 5.4 million nuclei collected by AMS is presented. The total error on each of the fluxes is 3%-4% at 100 GV, which is an improvement of more than a factor of 10 compared to previous measurements. Unexpectedly, the results show above 30 GV, these three fluxes have identical rigidity dependence and harden identically above 200 GV. In addition, my work on a new method of the tracker charge measurement leads to significant improvements in the AMS charge resolution, thus paving the way for the unexplored flux measurements of high Z cosmic rays.
by Yi Jia.
Ph. D.
10
Tao, Li. "Measurement of the cosmic lepton and electron fluxes with the AMS detector on board of the International Space Station. Monitoring of the energy measurement in the calorimeter". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GRENY016/document.
Testo completoAbstract (sommario):
Le Spectromètre Magnétique Alpha (AMS) est un détecteur de particules installé à bord de la Station Spatiale Internationale ; il enregistre des données depuis mai 2011. L'expérience a pour objectif d'identifier la nature des rayons cosmiques chargés et des photons et de mesurer leur flux dans la gamme d'énergie du GeV au TeV. Ces mesures permettent d'affiner les modèles de propagation de rayons cosmiques, d'effectuer une recherche indirecte de matière noire, et de chercher l'antimatière primordiale (anti-hélium). Dans ce mémoire, les données des premières années ont été utilisées pour mesurer les flux d'électrons et de leptons (électrons + positons) dans la gamme d'énergie de 0.5 GeV à 700 GeV. L'identification d'électrons nécessite une séparation électrons/protons de l'ordre de 104, obtenue par l'utilisation conjointe des estimateurs de différents sous-détecteurs d'AMS, en particulier du calorimètre électromagnétique (ECAL), du trajectomètre et du détecteur à radiation de transition (TRD). Dans cette analyse, les nombres d'électrons et de leptons sont estimés par un ajustement des distributions de l'estimateur du calorimètre et vérifiés en utilisant l'estimateur du TRD : 11 millions leptons ont été sélectionnés et analysés. Les incertitudes systématiques sont déterminées en variant les coupures de sélection et la procédure d'ajustement. L'acceptance géométrique du détecteur et les efficacités de sélection sont estimées grâce aux données de simulation. Les différences observées sur les échantillons de contrôle issus des données permettent de corriger la simulation. Les incertitudes systématiques associées à ces corrections sont établies en variant les échantillons de contrôle. Au total, à 100 GeV (resp. 700 GeV), l'incertitude statistique du flux de leptons est 2% (30%) et l'incertitude systématique est 3% (40%). Comme les flux se comportent globalement en loi de puissance en fonction de l'énergie, il est important de maitriser la calibration en énergie. Nous avons contrôlé in situ la mesure en énergie du calorimètre en comparant les électrons des données de vol et les données de tests en faisceaux, en utilisant en particulier la variable E/p ou p est la quantité de mouvement mesurée par le trajectomètre. Une deuxième méthode de calibration absolue à basse énergie, indépendante du trajectomètre, basée sur l'effet de la coupure géomagnétique a été développée. Deux modèles de prédiction de la coupure géomagnétique, l'approximation Störmer et le modèle IGRF, ont été testés et comparés. Ces deux méthodes ont permis de contrôler la calibration en énergie à 2% et de vérifier la stabilité des performances du calorimètre dans le tempsThe Alpha Magnetic Spectrometer (AMS) is a particle detector installed on the International Space Station; it starts to record data since May 2011. The experiment aims to identify the nature of charged cosmic rays and photons and measure their fluxes in the energy range of GeV to TeV. These measurements enable us to refine the cosmic ray propagation models, to perform indirect research of dark matter and to search for primordial antimatter (anti-helium). In this context, the data of the first years have been utilized to measure the electron flux and lepton flux (electron + positron) in the energy range of 0.5 GeV to 700 GeV. Identification of electrons requires an electrons / protons separation power of the order of 104, which is acquired by combining the information from different sub-detectors of AMS, in particular the electromagnetic calorimeter (ECAL), the tracker and the transition radiation detector (TRD). In this analysis, the numbers of electrons and leptons are estimated by fitting the distribution of the ECAL estimator and are verified using the TRD estimator: 11 million leptons are selected and analyzed. The systematic uncertainties are determined by changing the selection cuts and the fit procedure. The geometric acceptance of the detector and the selection efficiency are estimated thanks to simulated data. The differences observed on the control samples from data allow to correct the simulation. The systematic uncertainty associated to this correction is estimated by varying the control samples. In total, at 100 GeV (resp. 700 GeV), the statistic uncertainty of the lepton flux is 2% (30%) and the systematic uncertainty is 3% (40%). As the flux generally follows a power law as a function of energy, it is important to control the energy calibration. We have controlled in-situ the measurement of energy in the ECAL by comparing the electrons from flight data and from test beams, using in particular the E/p variable where p is momentum measured by the tracker. A second method of absolute calibration at low energy, independent from the tracker, is developed based on the geomagnetic cutoff effect. Two models of geomagnetic cutoff prediction, the Störmer approximation and the IGRF model, have been tested and compared. These two methods allow to control the energy calibration to a precision of 2% and to verify the stability of the ECAL performance with time
11
Weber, Niclas. "A measurement of the antiproton and proton fluxes in cosmic rays using the CAPRICE experiment". Doctoral thesis, KTH, Physics, 1997. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2469.
Testo completo
12
Chen, Hai Ph D. Massachusetts Institute of Technology. "Precision measurement of electron and positron flux in cosmic rays with the AMS-02 Detector". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/103243.
Testo completoAbstract (sommario):
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 159-169).
The cosmic ray electron and positron flux measurement can address a series of astrophysics and particle physics questions. This thesis presents an analysis of electron and positron flux from 0.5 GeV to 1 TeV using the first 30 months of data taking( over 41 billion events), with the AMS-02 detector on the International Space Station(ISS) 330-410 km above earth. A precise calibration of the Electromagnetic Calorimeter(ECAL) signals is performed to obtain stable energy measurement. A reconstruction algorithm for electromagnetic showers is implemented to measure energy and achieve high particle identification accuracy of electron and positron separating them from the proton background. The result of combined electron and positron flux measurement shows a smooth spectrum with no sharp structure. The spectral index ... above 30 GeV is observed to be ... (energy scale). This provides precise measurement for cosmic ray electrons and positrons and can contribute to probing the origin of cosmic rays, informing the studies of new physics..
by Hai Chen.
Ph. D.
13
Kislat, Fabian. "Measurement of the energy spectrum of cosmic rays with the 26 station configuration of the IceTop detector". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2012. http://dx.doi.org/10.18452/16443.
Testo completoAbstract (sommario):
IceTop ist ein Luftschauerdetektor am geographischen Südpol und die Oberflächenkomponente des Neutrinoteleskops IceCube. Seit der Fertigstellung im Dezember 2010 besteht IceTop aus 81 Detektorstationen auf einer Fläche von einem Quadratkilometer. Die vorliegende Dissertation umfasst eine Analyse von Daten, die im Jahr 2007 mit den 26 damals installierten Stationen genommen wurden. Dazu wurden zunächst Schauerposition und -richtung und ein Maß für die Größe des Schauers aus den Signalen rekonstruiert. Der Zusammenhang zwischen Primärenergie und Schauergröße wurde aus Monte-Carlo-Simulationen bestimmt. Dabei wurde eine Annahme über die chemische Zusammensetzung der kosmischen Strahlen gemacht. Damit wurde das Spektrum der Schauergrößen entfaltet um das Energiespektrum zu bestimmen. Dies wurde getrennt für verschiedene Zenitwinkelbereiche durchgeführt. Das Resultat der Entfaltung hängt von der angenommenen Massenkomposition ab. Die Ergebnisse, der Entfaltung in verschiedenen Zenitwinkelintervallen, müssen übereinstimmen, wenn man Isotropie der komischen Strahlung voraussetzt. Es wurde bereits gezeigt, dass dies ausgenutzt werden kann, um die möglichen Annahmen über die Zusammensetzung einzugrenzen. Eine gute Übereinstimmung von Spektren aus verschiedenen Zenitwinkelbereichen wird unter der Annahme von reinen Protonen als Primärteilchen gefunden, sowie für eine Mischung aus Protonen und Eisen mit einem hohen Protonanteil bei niedrigen Energien und einer Mehrheit von Eisen bei hohen Energien. Unter diesen Annahmen ergibt sich die Position des Knies im Spektrum zu 3,97 bis 4,20PeV. Der spektrale Index unterhalb des Knies ist etwa -2,7 und oberhalb des Knies variiert er zwischen -3,08 und -3,15. Reines Eisen auf der anderen Seite kann mit sehr großer Wahrscheinlichkeit ausgeschlossen werden. Unabhängig von der Annahme über die Zusammensetzung wird oberhalb von etwa 30PeV ein Abflachen des Spektrums mit einem Index von etwa -3,0 beobachtet.IceTop is an air shower array at the geographic South Pole. It is the surface component of the IceCube neutrino telescope. Since its completion in December 2010, IceTop consists of 81 detector stations covering an area of 1km². In this dissertation, an analysis of data taken in 2007 with 26 IceTop stations operational at that time is presented. Air showers were reconstructed in order to determine the location of the shower core, their direction and the shower size. The relation between primary energy and shower size was determined from Monte Carlo simulations. An assumption was made about the chemical composition of cosmic rays. The information obtained in these simulations were then used to unfold the spectrum of measured shower sizes in order to obtain the all-particle cosmic ray energy spectrum. This was done independently for particles from three different zenith angle intervals. The result of the unfolding depends on the assumed primary composition. Due to the isotropy of cosmic rays, results obtained in different zenith angle intervals must agree. It has already been shown that this requirement can be used to constrain the range of possible assumptions on the chemical composition of primary particles. Good agreement of spectra from different zenith angle ranges has been found under the assumption of pure proton primaries, as well as for a mixture of protons and iron with a relatively large proton contribution at low energies and proton dominance at high energies. Under these assumptions the knee of the cosmic ray energy spectrum has been observed at energies between 3.97 and 4.20PeV. The spectral index below the knee is about -2.7 and varies between -3.08 and -3.15 above the knee. Pure iron as primary particles can be excluded at a high confidence level below 25PeV. Independent of the primary composition assumption a flattening of the energy spectrum with an index of about -3.0 has been observed above 30PeV.
14
Schulz, Alexander [Verfasser], e J. [Akademischer Betreuer] Blümer. "Measurement of the Energy Spectrum and Mass Composition of Ultra-high Energy Cosmic Rays / Alexander Schulz. Betreuer: J. Blümer". Karlsruhe : KIT-Bibliothek, 2016. http://d-nb.info/1095665456/34.
Testo completo
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Schüssler, Fabian. "Measurement of the Energy Spectrum of Ultra-High Energy Cosmic Rays using Hybrid Data of the Pierre Auger Observatory". [S.l. : s.n.], 2008. http://digbib.ubka.uni-karlsruhe.de/volltexte/1000009955.
Testo completo
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Schüssler, Fabian. "Measurement of the energy spectrum of ultra-high energy cosmic rays using hybrid data of the Pierre Auger Observatory". Karlsruhe Forschungszentrum Karlsruhe, 2009. http://d-nb.info/995867089/34.
Testo completo
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Weidenhaupt, Klaus Frank [Verfasser]. "Antenna calibration and energy measurement of ultra-high energy cosmic rays with the Auger Engineering Radio Array / Klaus Frank Weidenhaupt". Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2014. http://d-nb.info/1065959966/34.
Testo completo
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Kühl, Patrick [Verfasser]. "Energy Spectra of near relativistic Galactic Cosmic Rays and Solar Energetic Particles - Extending the Measurement Capabilities of EPHIN / Patrick Kühl". Kiel : Universitätsbibliothek Kiel, 2017. http://d-nb.info/1141176114/34.
Testo completo
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Schüssler, Fabian [Verfasser]. "Measurement of the energy spectrum of ultra-high energy cosmic rays using hybrid data of the Pierre Auger Observatory / Fabian Schüssler". Karlsruhe : Forschungszentrum Karlsruhe, 2009. http://d-nb.info/995867089/34.
Testo completo
20
Fleischhack, Henrike [Verfasser], Gernot [Gutachter] Maier, Thomas [Gutachter] Lohse e Markus [Gutachter] Risse. "Measurement of the iron spectrum in cosmic rays with the VERITAS experiment / Henrike Fleischhack ; Gutachter: Gernot Maier, Thomas Lohse, Markus Risse". Berlin : Mathematisch-Naturwissenschaftliche Fakultät, 2017. http://d-nb.info/1125549734/34.
Testo completo
21
Hugo, Marcelo Rivera Bretel. "Measurement of the energy spectrum of cosmic rays above 3 x 10¹⁷ eV using the infill array of the Pierre Auger Observatory". Paris 7, 2013. http://www.theses.fr/2013PA077028.
Testo completoAbstract (sommario):
L'observatoire Pierre Auger, situé en Argentine, combine un réseau de surface, étendu sur 3000 km ^2 et composé de détecteurs Cherenkov, avec 4 télescopes de fluorescence pour mesurer des gerbes atmosphériques initiées par les rayons cosmiques d'ultra haute énergie. Cet observatoire "hybride" (en fonctionnement depuis 2004, et dont le déploiement a été achevé en 2008) est pleinement efficace pour des énergies de rayons cosmiques primaires supérieures à 10 ^18 eV, c'est-à-dire à partir de la cheville du spectre en énergie jusqu'aux plus hautes énergies. Après l'achèvement de l'observatoire principal, la collaboration Auger a débuté le déploiement de nouveaux instruments afin d'étendre la gamme d'énergie jusqu'à 0. 1EeV. Les extensions prévues comptent deux réseaux de surface resserés, dits "infill", d'espacement de 750m et 433m, avec des possibilités de détection de muons, et trois télescopes de fluorescence supplémentaires ayant un champ de vue d'élévation plus grande. Le réseau "infill" de 750m (couvrant environ 24km ^2) et les nouveaux télescopes sont aujourd'hui en fonctionnement. Leur but est la mesure des rayons cosmiques à partir d'en dessous du deuxième genou du spectre jusqu'à la cheville où les données recouvrent celles de l'observatoire principal. L'étude de l'évolution du spectre du deuxième genou à la cheville, alliée à la composition du rayon cosmique primaire, sont cruciales dans la compréhension de la transition de l'origine galactique à extragalactique des rayons cosmiques. Cette thèse s'appuie sur les données provenant du réseau "infill" de 750 m: l'objectif est la mesure du spectre en énergie des rayons cosmiques dans la région d'énergie au-dessus de 3x10 ^17 eV, où le réseau est pleinement efficace. Pour obtenir le spectre en énergie, plusieurs étapes sont nécessaires, à partir de la reconstruction des événements, en passant par la détermination exacte de l'exposition du réseau, jusqu'à la détermination de l'énergie du primaire. La thèse traite de ces aspects, avant d'atteindre le résultat final. Le premier chapitre donne une introduction générale de la physique des rayons cosmiques et des détecteurs associés. Il résume également les résultats expérimentaux au-dessus du première genou du spectre avec un accent particulier sur ceux obtenus au-dessus de 10 ^17 eV. Les deux chapitres suivants décrivent respectivement l'observatoire Pierre Auger et le réseau "infill". Dans le chapitre 2, après une description schématique des différentes composantes de l'observatoire, les principaux résultats obtenus par l'observatoire Auger sont résumés. Le chapitre 3 prépare le terrain pour les chapitres suivants. Il présente une description plus détaillée des caractéristiques du réseau "infill", en particulier la définition du trigger, la sélection et la reconstruction des événements. Dans le chapitre 4, la qualité de la reconstruction de la distribution latérale des gerbes observées est étudiée en détail. Ceci est particulièrement important pour le spectre en énergie, puisque le signal à une distance fixe de l'axe de la gerbe est utilisé comme estimateur de l'énergie de l'événement. Ce signal est estimé au moyen de la distribution latérale de la gerbe mesurée. Le chapitre 5 présente une comparaison entre la reconstruction d'événement du réseau "infill" et celle du réseau principal. En utilisant les gerbes détectées par les deux instruments, la géométrie et l'estimation de l'énergie obtenues sont comparées, montrant une bonne correspondance. Dans le chapitre 6 le seuil d'énergie du réseau, et donc l'ensemble des événements qui seront utilisés, est défini. Les méthodes pour obtenir l'exposition du réseau et les incertitudes systématiques associées sont discutées. Enfin, dans le chapitre 7, la technique pour obtenir l'énergie du primaire pour chaque gerbe détectée est présentée. Le spectre en énergie obtenu est discuté et le flux est montré compatible avec celui mesuré par d'autres instruments dans les régions d'énergie communesThe Pierre Auger Observatory, in Argentina, combines a 3000 $$\mathrm{km^2}$$ surface array of water Cherenkov detectors with fluorescence telescopes to measure extensive air showers initiated by ultra-high energy cosmic rays. This "hybrid" observatory (in operation since 2004, and completed in 2008) is fully efficient for cosmic rays energies above $$10^{18}$$ eV, that is, from just below the "ankle" of the energy spectrum up to the highest energies. After the completion of the main observatory, the Auger collaboration has started to deploy new instruments to extend the energy range down to about 0. 1 EeV. The planned extensions include two infill surface arrays with 750 and 433 m spacing, with muon detection capabilities, and three additional fluorescence telescopes with a more elevated field of view. The 750 m infill array (covering about 24 $$\mathrm{km^2}$$) and the new telescopes are now operational. Their aim is the measurement of cosmic rays from below the second knee of the spectrum up to the ankle, where data from the extensions overlap those from the main observatory. The study of the evolutior of the spectrum through the second knee and the ankle, together with the primary mass composition, are crucial to the understanding of the transition from a galactic cosmic ray origin to an extragalactic one. This thesis makes use of data from the 750 m infill array: the objective is the measurement of the cosmic ray energy spectrum in the energy region above $$3 \times 10^{17}$$ eV, where the array is fully efficient. To get to the energy spectrum, several steps are needed, from the reconstruction of events, through the precise determination of the exposure of the array, up to the determination of the primary energy. The thesis deals with these aspects, before reaching the final result. The first chapter gives a general introduction to cosmic ray physics and detectors. It also summarizes experimental results above the first knee of the spectrum with particular emphasis on those obtained above $$10^{17}$$ eV. The next two chapters describe the Pierre Auger Observatory and the infill array, respectively. In chapter 2, the main Auger results are summarized too, after a schematic description of th different components of the observatory. Chapter 3 sets the stage for the following chapters. It presents a more detailed description of the characteristics of the infill array, in particular the trigger definitions, event selection and reconstruction. In chapter 4 the performance of the reconstruction of the lateral distribution of observed showers is studied in detail. This is particularly important for the energy spectrum, since the signal at a fixed distance from the shower axis is used as the energy estimator of the event. This signal is estimated by means c the measured lateral distribution of the shower. Chapter 5 presents a comparison between the event reconstruction of the infill and main arrays. Using the set of showers detected by both instruments, the derived geometry and energy estimation are compared, showing a good agreement. In chapter 6, the energy threshold of the array, and hence the set of events to be used, is defined. The methods to obtain the exposure of the array are discussed, as well as related systematic uncertainties. Finally, in chapter 7, the technique to derive the primary energy for each detected shower is presented. The derived energy spectrum is discussed, and the flux is shown to be consistent with that measured by other instruments in the overlapping energy regions
22
Getley, Ian L. Department of Aviation Faculty of Science UNSW. "Cosmic and solar radiation monitoring of Australian commercial flight crew at high southern latitudes as measured and compared to predictive computer modelling". Awarded by:University of New South Wales, 2007. http://handle.unsw.edu.au/1959.4/40536.
Testo completoAbstract (sommario):
This study set out to examine the levels of galactic cosmic radiation exposure to Australian aircrew during routine flight operations, with particular attention to the high southern latitude flights between Australia and South Africa. Latitudes as high as 65?? South were flown to gain the data and are typical of the normal flight routes flown between Sydney and Johannesburg on a daily basis. In achieving this objective it became evident that suitable commercially available radiation monitoring equipment was not readily available and scientific radiation monitors were sourced from overseas research facilities to compliment my own FH4lB and Liulin monitors provided by UNSW. At the same time it became apparent that several predictive codes had been developed to attempt to model the radiation doses received by aircrew based on flight route, latitudes and altitudes. Further, it became apparent that these codes had not been subjected to verification at high southern latitudes and that they had not been validated for the effects of solar particle events. Initially measurements were required at the high latitudes followed by mid-latitude data to further balance the PCAIRE code to ensure reasonableness of results for both equatorial and high latitudes. Whilst undertaking this study new scientific monitors became available which provided an opportunity to observe comparative data and results. The Liulin, QDOS and a number of smaller personal dosimeters were subsequently obtained and evaluated. This appears to be the first time that such an extensive cross comparison of these monitors has been conducted over such a wide range of latitudes and altitudes. During the course of this study a fortuitous encounter with GLE 66 enabled several aspects of code validation to be examined, namely the inability of predictive codes to estimate the increased dose associated with a GLE or the effects of a Forbush decrease on the code results. Finally I review the known biological effects as discussed by numerous authors based on current epidemiological studies, with a view to high-lighting were the advent of future technology in aviation may project aircrew dose levels.
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Göttfert, Tobias. "Background suppression for a top quark mass measurement in the lepton+jets tt decay channel and alignment of the ATLAS silicon detectors with cosmic rays". kostenfrei, 2010. https://mediatum2.ub.tum.de/node?id=956486.
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Plum, Matthias [Verfasser], Thomas Akademischer Betreuer] Hebbeker e Christopher Henrik V. [Akademischer Betreuer] [Wiebusch. "Measurement of the chemical composition of ultra high energy cosmic rays with the HEAT telescopes of the Pierre Auger Observatory / Matthias Plum ; Thomas Hebbeker, Christopher Wiebusch". Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1156922151/34.
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Klepser, Stefan. "Reconstruction of extensive air showers and measurement of the cosmic ray energy spectrum in the range of 1 - 80 PeV at the South Pole". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2008. http://dx.doi.org/10.18452/15790.
Testo completoAbstract (sommario):
IceTop ist ein Detektorfeld fuer kosmische Strahlung, das momentan am Suedpol errichtet wird. Es ist Teil des IceCube-Observatoriums und wird nach Fertigstellung eine Flaeche von 1km^2 ueberspannen. Es zielt auf den Nachweis von Teilchenkaskaden ab, die von kosmischer Strahlung mit Energien im PeV-Bereich induziert werden. Die Dissertation beinhaltet die erste Analyse hochenergetischer kosmischer Strahlung mit IceTop. Zunaechst wird hierfuer die Lichtausbeute der Detektortanks untersucht. Dies ermoeglicht die Erstellung einer Erwartungswertverteilung der Schauersignale, und eines entsprechenden Likelihood-Rekonstruktionsalgorithmus. Die damit erreichten Aufloesungen werden untersucht und Effizienzen berechnet. Anschliessend wird das Ansprechverhaltenn von IceTop im Bezug auf die Energie genauer evaluiert. Aus den Ergebnissen werden Faltungsmatrizen fuer unterschiedliche Primaerteilchensorten extrahiert. Darauf basierend werden zwei Entfaltungsalgorithmen vorgestellt, und vier Faltungsmatrizen fuer verschiedene Kompositionsannahmen berechnet. Im August 2007 genommene Daten werden in drei Zenithwinkel-Abschnitte eingeteilt und separat mit den Kompositionsmodellen entfaltet. Die resultierenden Spektren decken einen Energiebereich von 1-80PeV ab. Mit der Forderung isotropen Flusses lassen sich Wahrscheinlichkeiten definieren, die sensitiv sind auf die Konsistenz der Kompositionsannahmen. Diese neue Methode ermoeglicht eine Untersuchung der Komposition ohne Zuhilfenahme weiterer Detektorkomponenten. Die Analyse zeigt eine klare Praeferenz der Modelle gemischter Komposition. Schliesslich wird das Spektrum mit der hoechsten relativen Wahrscheinlichkeit untersucht. Die gemessenen Parameter stimmen innerhalb der systematischen Fehler gut mit denen anderer Experimente ueberein. Die ermittelte Position des sogenannten Knies des Spektrums ist 3,1+-0,3(stat.)+-0,3(sys.)PeV, die Exponenten davor und danach sind -2,71+-0,07(stat.) und -3,110+-0,014(stat.)+-0,08(sys.).IceTop is a square-kilometer scale detector array for highly energetic cosmic radiation. It is a part of the IceCube Observatory that is presently being built at the geographic South Pole. It aims for the detection of huge particle cascades induced by PeV cosmic rays in the atmosphere. This thesis presents the first analysis of highly energetic cosmic ray data taken with IceTop. First, the light response of the IceTop tanks is parametrised as a function of energy and particle type. An expectation function for the distribution of shower signals in the detector plane is developed. Based on that, a likelihood reconstruction algorithm is developed and its resolution and performance is studied. The resulting energy response of the array is investigated to set up response matrices for different primary nuclei and inclinations. Two unfolding algorithms are implemented, and response matrices are modeled for four different composition assumptions. With each assumption, energy spectra are unfolded for three different bins in inclination, using a data sample taken in August 2007. The range of the spectrum is 1-80PeV. Finally, a new analysis method is developed that uses the fact that cosmic rays in the PeV range are expected to be isotropic. It is shown that this requirement can be used for a likelihood estimation that is sensitive to composition without using additional information from other detector components. The analysis shows a clear preference of the mixed composition models over pure proton or iron assumption. The spectrum with the highest likelihood shows good agreement with results from other experiments within the systematic uncertainties. The found position of the so-called knee feature is 3.1+-0.3(stat.)+-0.3(sys.)PeV, the power indices before and after that are -2.71+-0.07(stat.) and -3.110+-0.014(stat.)+-0.08 (sys.).
26
Porcelli, Alessio [Verfasser], e J. [Akademischer Betreuer] Blümer. "Measurement of the Depth of Shower Maximum in the Transition Region between Galactic and Extragalactic Cosmic Rays with the Pierre Auger Observatory / Alessio Porcelli. Betreuer: J. Blümer". Karlsruhe : KIT-Bibliothek, 2014. http://d-nb.info/1059157489/34.
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Kislat, Fabian [Verfasser], Hermann [Akademischer Betreuer] Kolanoski, Thomas K. [Akademischer Betreuer] Gaisser e Gernot [Akademischer Betreuer] Maier. "Measurement of the energy spectrum of cosmic rays with the 26 station configuration of the IceTop detector / Fabian Kislat. Gutachter: Hermann Kolanoski ; Thomas K. Gaisser ; Gernot Maier". Berlin : Humboldt Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2012. http://d-nb.info/1019165642/34.
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Heil, Melanie [Verfasser], e W. de [Akademischer Betreuer] Boer. "Measurement of the positron fraction in cosmic rays from 0.5-350 GeV with the AMS-02 detector on the International Space Station / Melanie Heil. Betreuer: W. de Boer". Karlsruhe : KIT-Bibliothek, 2013. http://d-nb.info/1037154355/34.
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Painter, William [Verfasser], e J. [Akademischer Betreuer] Blümer. "Development of a SiPM camera for detection and measurement of fluorescence emission from extensive air-showers generated by ultra high energy cosmic rays / William Painter ; Betreuer: J. Blümer". Karlsruhe : KIT-Bibliothek, 2019. http://d-nb.info/1197138757/34.
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Andreasen, Mie, Karsten H. Jensen, Marek Zreda, Darin Desilets, Heye Bogena e Majken C. Looms. "Modeling cosmic ray neutron field measurements". AMER GEOPHYSICAL UNION, 2016. http://hdl.handle.net/10150/621996.
Testo completoAbstract (sommario):
The cosmic ray neutron method was developed for intermediate-scale soil moisture detection, but may potentially be used for other hydrological applications. The neutron signal of different hydrogen pools is poorly understood and separating them is difficult based on neutron measurements alone. Including neutron transport modeling may accommodate this shortcoming. However, measured and modeled neutrons are not directly comparable. Neither the scale nor energy ranges are equivalent, and the exact neutron energy sensitivity of the detectors is unknown. Here a methodology to enable comparability of the measured and modeled neutrons is presented. The usual cosmic ray soil moisture detector measures moderated neutrons by means of a proportional counter surrounded by plastic, making it sensitive to epithermal neutrons. However, that configuration allows for some thermal neutrons to be measured. The thermal contribution can be removed by surrounding the plastic with a layer of cadmium, which absorbs neutrons with energies below 0.5 eV. Likewise, cadmium shielding of a bare detector allows for estimating the epithermal contribution. First, the cadmium difference method is used to determine the fraction of thermal and epithermal neutrons measured by the bare and plastic-shielded detectors, respectively. The cadmium difference method results in linear correction models for measurements by the two detectors, and has the greatest impact on the neutron intensity measured by the moderated detector at the ground surface. Next, conversion factors are obtained relating measured and modeled neutron intensities. Finally, the methodology is tested by modeling the neutron profiles at an agricultural field site and satisfactory agreement to measurements is found.
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Wu, Juan. "Measurements of Cosmic Ray Antiprotons with PAMELA". Licentiate thesis, KTH, Particle and Astroparticle Physics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12378.
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Zhou, Feng Ph D. Massachusetts Institute of Technology. "Cosmic ray lithium isotope measurement with AMS-01". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/63009.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 105-112).
The AMS-01 detector measured charged cosmic rays during 10 days on the Space Shuttle Discovery in 1998 and collected 108 events. By identifying 8349 Lithium and 22709 Carbon nuclei from the raw data, this thesis presents the measurement of cosmic ray Lithium to Carbon ratio of presently highest statistics and momentum resolutions in the rigidity range of 2 GV to 100 GV. The 7Li to 6Li ratio is measured to be 1.07±0.16 in the rigidity region achieved from 2.5 GV to 6.3 GV. The experimental results are used to provide constraints on cosmic ray propagation models and address the "Lithium Problems".
by Feng Zhou.
Ph.D.
33
Mocchiutti, Emiliano. "Atmospheric and Interstellar Cosmic Rays Measured With the CAPRICE98 Experiment". Doctoral thesis, KTH, Physics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3643.
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34
Bultena, Sandra Lyn. "Direction measurement capabilities of the LEDA cosmic ray detector". Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63930.
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Murthy, Kavita. "Energy measurement capabilities of the LEDA cosmic ray detector". Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64058.
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36
Cossavella, Fabiana. "Measurements of high energy cosmic rays above 10 PeV with KASCADE-Grande". Eggenstein-Leopoldshafen Forschungszentrum Karlsruhe GmbH, 2009. http://d-nb.info/999765329/34.
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Alsop, C. "A large detector for cosmic ray abundance and energy measurements". Thesis, University of Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384391.
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Cossavella, Fabiana [Verfasser]. "Measurements of high energy cosmic rays above 10 PeV with KASCADE-Grande / Fabiana Cossavella". Eggenstein-Leopoldshafen : Forschungszentrum Karlsruhe GmbH, 2009. http://d-nb.info/999765329/34.
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Lee, Ka-pik, e 李嘉碧. "Studies of gadolinium-loaded liquid scintillator used in the Aberdeen tunnel experiment in Hong Kong". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41508658.
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Camp, David L. "Using a two-scintillator paddle telescope for cosmic ray flux measurements". Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/phy_astr_theses/17.
Testo completoAbstract (sommario):
A two-scintillator paddle muon telescope with variable angular acceptance at the earth's surface was used to study correlations between flux distribution and barometric pressure. The detector was placed in 2 different locations around Georgia State University with varying paddle separations of 0, 7, and 14 inches. Correlation and anti-correlation analyses were conducted by using the muon count from the detector along with the barometric pressure, surface temperature, stratospheric temperature and solar activity. It was observed that there was a short and long-term variation relationship between cosmic ray counts and barometric pressure and also cosmic ray counts and temperature. No significant relationship was found between cosmic ray flux and solar activity. A new two-scintillator paddle telescope with larger detecting area was constructed in order to observe a stronger correlation between cosmic ray flux and pressure.
41
Rivera, Villarreyes Carlos Andres. "Cosmic-ray neutron sensing for soil moisture measurements in cropped fields". Phd thesis, Universität Potsdam, 2014. http://opus.kobv.de/ubp/volltexte/2014/6974/.
Testo completoAbstract (sommario):
This cumulative dissertation explored the use of the detection of natural background of fast neutrons, the so-called cosmic-ray neutron sensing (CRS) approach to measure field-scale soil moisture in cropped fields. Primary cosmic rays penetrate the top atmosphere and interact with atmospheric particles. Such interaction results on a cascade of high-energy neutrons, which continue traveling through the atmospheric column. Finally, neutrons penetrate the soil surface and a second cascade is produced with the so-called secondary cosmic-ray neutrons (fast neutrons). Partly, fast neutrons are absorbed by hydrogen (soil moisture). Remaining neutrons scatter back to the atmosphere, where its flux is inversely correlated to the soil moisture content, therefore allowing a non-invasive indirect measurement of soil moisture.
The CRS methodology is mainly evaluated based on a field study carried out on a farmland in Potsdam (Brandenburg, Germany) along three crop seasons with corn, sunflower and winter rye; a bare soil period; and two winter periods. Also, field monitoring was carried out in the Schaefertal catchment (Harz, Germany) for long-term testing of CRS against ancillary data.
In the first experimental site, the CRS method was calibrated and validated using different approaches of soil moisture measurements. In a period with corn, soil moisture measurement at the local scale was performed at near-surface only, and in subsequent periods (sunflower and winter rye) sensors were placed in three depths (5 cm, 20 cm and 40 cm). The direct transfer of CRS calibration parameters between two vegetation periods led to a large overestimation of soil moisture by the CRS. Part of this soil moisture overestimation was attributed to an underestimation of the CRS observation depth during the corn period ( 5-10 cm), which was later recalculated to values between 20-40 cm in other crop periods (sunflower and winter rye).
According to results from these monitoring periods with different crops, vegetation played an important role on the CRS measurements. Water contained also in crop biomass, above and below ground, produces important neutron moderation. This effect was accounted for by a simple model for neutron corrections due to vegetation. It followed crop development and reduced overall CRS soil moisture error for periods of sunflower and winter rye.
In Potsdam farmland also inversely-estimated soil hydraulic parameters were determined at the field scale, using CRS soil moisture from the sunflower period. A modelling framework coupling HYDRUS-1D and PEST was applied. Subsequently, field-scale soil hydraulic properties were compared against local scale soil properties (modelling and measurements). Successful results were obtained here, despite large difference in support volume. Simple modelling framework emphasizes future research directions with CRS soil moisture to parameterize field scale models.
In Schaefertal catchment, CRS measurements were verified using precipitation and evapotranspiration data. At the monthly resolution, CRS soil water storage was well correlated to these two weather variables. Also clearly, water balance could not be closed due to missing information from other compartments such as groundwater, catchment discharge, etc. In the catchment, the snow influence to natural neutrons was also evaluated. As also observed in Potsdam farmland, CRS signal was strongly influenced by snow fall and snow accumulation. A simple strategy to measure snow was presented for Schaefertal case.
Concluding remarks of this dissertation showed that (a) the cosmic-ray neutron sensing (CRS) has a strong potential to provide feasible measurement of mean soil moisture at the field scale in cropped fields; (b) CRS soil moisture is strongly influenced by other environmental water pools such as vegetation and snow, therefore these should be considered in analysis; (c) CRS water storage can be used for soil hydrology modelling for determination of soil hydraulic parameters; and (d) CRS approach has strong potential for long term monitoring of soil moisture and for addressing studies of water balance.In dieser kumulativen Dissertation wird die Detektion des natürlichen Hintergrunds von schnellen Neutronen, das sogenannte “Cosmic-Ray Neutron Sensing” (CRS), zur Messung von Bodenfeuchte auf der Feldskala in landwirtschaftlich genutzten Flächen untersucht. Die kosmische Primärstrahlung durchdringt die oberste Atmosphäre, und interagiert mit atmosphärischen Teilchen. Durch diese Wechselwirkungen entstehen Kaskaden hochenergetischer Teilchen die bis in die Erdoberfläche eindringen, wobei schnelle Neutronen entstehen. Teilweise werden diese durch Wasserstoff (Bodenfeuchte) absorbiert, teilweise zurück in die Atmosphäre gestreut. Dieser Neutronenfluss über dem Boden korreliert invers mit der Bodenfeuchte, was so eine non-invasive und indirekte Bodenfeuchteschätzung ermöglicht. Die CRS-Methode wird vor allem in einer Feldstudie auf einem Ackerland in Potsdam (Brandenburg, Deutschland), einschließlich dreier Phasen mit Anbau von Mais, Sonnenblume und Winterroggen getestet und beurteilt. Darüber hinaus wurde ein Feldmonitoring im Schäfertaleinzugsgebiet (Harz, Deutschland) durchgeführt, um das Potential von Langzeit-CRS-Messungen gegenüber herkömmlich erhobenen bodenhydraulischen Daten abzuschätzen. Im ersten Untersuchungsgebiet wurde die CRS-Methode kalibriert und mittels verschiedener Bodenfeuchtemessansätze validiert. In der Maisanbauphase wurden die Bodenfeuchte-Punktmessungen zunächst nur an der nahen Bodenoberfläche durchgeführt. In den folgendenen Anbauphasen (Sonnenblume und Winterroggen) wurden dann die Sensoren in drei unterschiedlichen Tiefen (5 cm, 20 cm und 40 cm) installiert. Die direkte Übertragung der CRS-Kalibrierparameter zwischen zwei Vegetationsperioden führte zu einer starken Überschätzung der CRS-Bodenfeuchte. Ein Teil der überschätzten Bodenfeuchte wurde der Unterschätzung der CRS-Beobachtungstiefe während der Maisperiode (5-10 cm) zugeschrieben, welche später basierend auf Werten zwischen 20-40 cm in anderen Anbauperioden (Sonnenblume und Winterroggen) neuberechnet wurde. Gemäß der Ergebnisse dieser Beobachtungsperioden mit verschiedenen Feldfrüchten, spielte die Vegetation eine wichtige Rolle für die CRS-Messungen, da das Wasser, das in der über- und unterirdischen Biomasse vorhanden ist, die Neutronen bedeutend abdämpft. Dieser Effekt, sowie der Einfluss des Getreidewachstums und des reduzierten Gesamt-CRS-Bodenfeuchte-Fehlers, wurden in ein einfaches Model zur vegetationsbedingten Neutronenkorrektur berücksichtigt. So wurde ein gekoppelter HYDRUS-1D- und PEST-Ansatz angewendet, um bodenhydraulische Parameter auf dem Feldmassstab während der Sonnenblumen-Phase invers abzuschätzen. Dann wurden die inversen Schätzungen der effektiven bodenhydraulischen Eigenschaften innerhalb des von CRS beobachteten Volumens durch die lokalen Bodeneigenschaften (Modellierung und Messungen) validiert. Abgesehen von Unterschieden auf Grund der Beobachtungstiefe und somit des Volumens, wurden hierbei erfolgreiche Ergebnisse erzielt. Dieser einfache Ansatz unterstreicht das zukünftige Forschungspotential, z.B. um mit Hilfe von Bodenfeuchten aus CRS-Messungen Modelle auf der Feldskala zu parametrisieren. Im Schäfertaleinzugsgebiet wurden die Langzeit-CRS-Messungen mit Nie-derschlags- und Evapotranspirations-Raten abgeglichen. Bei einer monatlichen Auflösung korrelierte die Änderung des CRS-Bodenwasserspeichers mit diesen beiden Wettervariablen. Die Wasserbilanz konnte jedoch auf Grund fehlender Informationen bezüglich Grundwasser, Abfluss des Einzugesgebiets, etc. nicht geschlossen werden. Darüber hinaus wurde, wie auch am Potsdamer Standort, festgestellt, dass das CRS-Signal stark von Schneefall und Schneeakkumulationen beeinflusst wird. Eine einfache Anwendung zur Schneemessung mittels CRS wurde für den Schäfertalfall vorgestellt. Abschließend zeigte sich, dass (a) „Cosmic-Ray Neutron Sensing“ (CRS) ein großes Potential hat, Messungen der mittleren Bodenfeuchte auf der Feldskala im Bereich landwirtschaftlich genutzter Flächen zu realisieren; (b) die CRS-Bodenfeuchte stark durch andere Wasserspeicher, wie Vegetation und Schnee beeinflusst wird, und dies im Rahmen von Analysen berücksichtigt werden sollte; (c) die CRS-Messungen über eine bodenhydraulische Modellierung zur Bestimmung von bodenhydraulischen Paramtern genutzt werden kann; und (d) der CRS-Ansatz ein großes Potential für Langzeit-Bodenfeuchte-Monitoring und für Wasserbilanzstudien hat.
42
Nehls, Steffen. "Calibrated measurements of the radio emission of cosmic ray air showers". Karlsruhe : Forschungszentrum Karlsruhe, 2008. http://d-nb.info/992107431/34.
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Grove, Jon Eric Stone Edward Stone Edward. "A balloon measurement of the isotopic composition of galactic cosmic ray iron /". Diss., Pasadena, Calif. : California Institute of Technology, 1989. http://resolver.caltech.edu/CaltechETD:etd-05312007-121425.
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Lordello, Vitor Diorio. "Cosmic ray 2H/1H flux ratio measurement with the AMS-02 experiment". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-30012018-163850/.
Testo completoAbstract (sommario):
The Alpha Magnetic Spectrometer (AMS-02) is a cosmic ray detector operating aboard the International Space Station (ISS) since May 2011. The identification of cosmic ray deuterium and hydrogen particles is the main goal of this work. Using the data collected by the AMS-02 experiment between May 2011 and May 2014 we provide the measurement of the 2H to the 1H ratio between 0.7 and 7 GeV/n. Cosmic rays are mainly composed of hydrogen nuclei. No significant amount of deuterium nuclei is expected to be released from galactic sources since they are destroyed rather than formed in thermonuclear reactions inside stars. As a consequence of their production history, they are part of a class of secondary stable nuclei that provide information on the propagation of cosmic rays in the galaxy. Despite their relevance for propagation studies, very few measurements of deuterium exist above 1 GeV/n, due to the poor isotopic separation capacity of previous experiments. For this reason, the deuterium to hydrogen flux ratio is a very important measurement to be carried out using the data collected by the AMS-02 experiment. The mass and the isotopic composition of cosmic-rays nuclei can be measured by the AMS-02 experiment using measurements of the momentum (provided by the tracker) and velocity of the particles (provided by the Time-of-Flight and the RICH). This analysis is one of the first to be focused on hydrogen isotopic composition with AMS-02 data, and our results are in fair agreement with a similar and independent analysis that has been carried out within the Collaboration.O Espectômetro Magnético Alpha (AMS-02) é um detetor de raios cósmicos operando na Estação Espacial Internacional (ISS) desde maio de 2011. O principal objetivo deste trabalho é a identificação de deutério e hidrogênio nos raios cósmicos. Usando dados coletados pelo experimento AMS-02 entre maio de 2011 e maio de 2014 foi medida a razão entre os fluxos de 2H e 1H entre 0.7 e 7 GeV/n. Raios cósmicos são compostos, principalmente, por núcleos de hidrogênio. Não é esperado que fontes galácticas de raios cósmicos liberem uma quantidade significativa de núcleos de deutério, já que eles são destruidos, em vez de formados, nas reações termonucleares no interior de estrelas. Assim, eles fazem parte de uma classe de partículas secundárias estáveis que fornecem informações acerca da propagação de raios cósmicos na galáxia. Apesar da relevância para o estudo da propagação de raios cósmicos, poucas medidas da sua quantidade acima de 1 GeV/n existem, devido à baixa capacidade de separação de isótopos de prévios experimentos. Por isso a razão entre os fluxos de deutério e hidrogênio é uma importante medida a ser feita com os dados do AMS-02. A massa, e portanto a composição isotópica dos raios cósmicos, pode ser medida pelo AMS-02 a partir das medições de momento (realizada pelo tracker) e velocidade (realizadas pelo ToF e RICH). Essa análise é uma das primeiras a focar na composição isotópica do hidrogênio com dados do AMS-02, e os resultados estão razoavelmente em acordo com análises independendes semelhantes realizadas na colaboração AMS.
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Mikuni, Vinicius Massami. "Measurement of cosmic ray electrons and positrons with the AMS-02 experiment". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-29092017-143310/.
Testo completoAbstract (sommario):
The Alpha Magnetic Spectrometer (AMS-02) is a high-energy particle physics detector operating on the International Space Station (ISS) since May 2011. Since its launch, the AMS-02 provided a large amount of data whose precision was never before achieved, opening a new path for the study of cosmic rays (CRs). The first published results of AMS-021-3 show tension with the current understanding of the cosmic ray theory, particularly at higher energies. These tensions are directly linked to many fundamental questions like the dark matter nature, the CR origin and their propagation through the galaxy. This work presents the measurement of the electron flux and the positron flux in primary cosmic rays, based on the data collected between May 2011 and November 2016, an extended data set with respect to the published AMS-02 results.3 The results extend the energy range explored up to 1 TeV for electrons and up to 700 GeV for positrons, being consistent with the published results when using the same data set. A discrepancy between the new measurement and the published flux is observed in the low energy region of the electron flux, while the positron flux is in good agreement. This can be explained by a charge dependent solar modulation effect. This hypothesis was investigated by studying the time evolution of the fluxes, focusing on the energy region below 40 GeV, where an electron and positron flux is computed over 74 time bins of 27 days width, corresponding to the suns rotation period as seen from the Earth. The time dependent analysis confirms hints of charge dependent solar modulation, that are also observed by other independent analysis that have been carried out in parallel within the collaboration.O Alpha Magnetic Spectrometer (AMS-02) é um experimento de física de partículas instalado na Estação Espacial Internacional (ISS) desde Maio de 2011. Desde seu lançamento, AMS-02 coleta uma quantidade de dados com tal precisão que até então nunca foram jamais vistos, abrindo o caminho para o estudo dos Raios Cósmicos (CRs). Os primeiros resultados publicados pelo AMS-021-3 apresentam tensões com o modelo atual da teoria de CRs, particularmente nas altas energias. Essas tensões são diretamente ligadas a diversas questões fundamentais como a natureza da Matéria Escura (DM), a origem dos CRs e suas propagações pela galáxia. Este trabalho apresenta a medição do fluxo de elétrons e pósitrons em CRs primários, baseando-se nos dados coletados entre Maio de 2011 e Novembro de 2016, período extendido com relação aos resultados públicados pelo AMS-02.3 Os resultados extendem o intervalo de energia explorado para 1 TeV para elétrons e 700 GeV ára pósitrons, consistentes com os resultados públicados usando o mesmo período. Discrepância entre a nova medição e o fluxo públicado é observada na região de baixas energias para o fluxo de elétrons, enquanto o fluxo de pósitrons continua em bom acordo. O resultado pode ser explicado por uma dependência na carga causada pela modulação solar. Tal hipótese é investigada estudando-se a evolução temporal dos fluxos, focando-se no intervao de energia abaixo de 40 GeV, onde um fluxo de elétrons e pósitrons é medido durante 74 intervalos temporais de 27 dias, correspondendo à rotação do sol vista da Terra. A análise dependente do tempo confirma a existência da dependência de carga da modulação solar, também observada por outras análises independentes que foram feitas dentro da colaboração.
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Hiller, Roman [Verfasser], e J. [Akademischer Betreuer] Blümer. "Radio measurements for determining the energy scale of cosmic rays / Roman Hiller. Betreuer: J. Blümer". Karlsruhe : KIT-Bibliothek, 2016. http://d-nb.info/1097380858/34.
Testo completo
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Perrett, J. C. "Measurements of scintillation and water-Cerenkov detector densities in extensive air showers produced by 10sup(16) - 5x10sup(19) eV cosmic rays". Thesis, University of Leeds, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355950.
Testo completo
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Wu, Juan. "Measurements of cosmic ray antiprotons with PAMELA and studies of propagation models". Doctoral thesis, KTH, Partikel- och astropartikelfysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-95331.
Testo completoAbstract (sommario):
Studying the acceleration and propagation mechanisms of Galactic cosmic rays can provide information regarding astrophysical sources, the properties of our Galaxy, and possible exotic sources such as dark matter. To understand cosmic ray acceleration and propagation mechanisms, accurate measurements of different cosmic ray elements over a wide energy range are needed. The PAMELA experiment is a satellite-borne apparatus which allows different cosmic ray species to be identified over background. Measurements of the cosmic ray antiproton flux and the antiproton-to-proton flux ratio from 1.5 GeV to 180 GeV are presented in this thesis, employing the data collected between June 2006 and December 2008. Compared to previous experiments, PAMELA extends the energy range of antiproton measurements and provides significantly higher statistics. During about 800 days of data collection, PAMELA identified approximately 1300 antiprotons including 61 above 31.7 GeV. A dramatic improvement of statistics is evident since only 2 events above 30 GeV are reported by previous experiments. The derived antiproton flux and antiproton-to-proton flux ratio are consistent with previous measurements and generally considered to be produced as secondary products when cosmic ray protons and helium nuclei interact with the interstellar medium. To constrain cosmic ray acceleration and propagation models, the antiproton data measured by PAMELA were further used together with the proton spectrum reported by PAMELA, as well as the B/C data provided by other experiments. Statistical tools were interfaced with the cosmic ray propagation package GALPROP to perform the constraining analyses. Different diffusion models were studied. It was shown in this work that only current PAMELA data, i.e. the antiproton-to-proton ratio and the proton flux, are not able to place strong constraints on propagation parameters. Diffusion models with a linear diffusion coefficient and modified diffusion models with a low energy dependence of the diffusion coefficient were studied in the $\chi^{2}$ study. Uncertainties on the parameters and the goodness of fit of each model were given. Some models are further studied using the Bayesian inference. Posterior means and errors of the parameters base on our prior knowledge on them were obtained in the Bayesian framework. This method also allowed us to understand the correlation between parameters and compare models. Since the B/C ratio used in this analysis is from experiments other than PAMELA, future PAMELA secondary-to-primary ratios (B/C, $^{2}$H/$^{4}$He and $^{3}$He/$^{4}$He) can be used to avoid the data sets inconsistencies between different experiments and to minimize uncertainties on the solar modulation parameters. More robust and tighter constraints are expected. The statistical techniques have been demonstrated useful to constrain models and can be extended to other observations, e.g. electrons, positrons, gamma rays etc. Using these channels, exotic contributions from, for example, dark matter will be further investigated in future.QC 20120523
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Nehls, Steffen [Verfasser]. "Calibrated measurements of the radio emission of cosmic ray air showers / Steffen Nehls". Karlsruhe : FZKA, 2008. http://d-nb.info/998341746/34.
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Nierstenhoefer, Nils [Verfasser]. "On the Origin and Propagation of Ultra-High Energy Cosmic Rays (Measurements & Prediction Techniques) / Nils Nierstenhoefer". Wuppertal : Universitätsbibliothek Wuppertal, 2011. http://d-nb.info/101622592X/34.
Testo completo