Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The IceCube Neutrino Telescope is designed to detect high energy neutrinos with a large array of photomultiplier tubes placed deep within the Antarctic ice. The way that light propagates through the ice needs to be modelled accurately to enable the paths of charged particles to be reconstructed from the distribution of their Cerenkov radiation. Light travelling through even the purest of ice will undergo scattering and absorption processes, however the ice in which IceCube is embedded has optical properties that vary significantly with depth which need to be accurately modelled. Currently, simulation of the muon background using the current ice model is unable to fully replicate experimental data. In this thesis we investigate a potential method of improving on the current generation of ice models. We introduce thin, highly absorbing layers into the current description of the detection medium and investigate the effect on the simulation of muon tracks in IceCube. We find that better agreement between simulation and data can be seen in the occupancy of optical modules, through the introduction of such absorptive layers into the existing ice layers.

Existierende Neutrinoteleskope sind für den Nachweis von Neutrinos aus astrophysikalischen Quellen mit Energien im TeV Bereich optimiert. Aufgrund der geringen Flüsse und Wirkungsquerschnitte wurden bislang keine extraterrestrischen hochenergetischen Neutrinos beobachtet. Erst die im Bau befindlichen kubikkilometer-großen Cherenkov-Neutrinodetektoren werden das notwendige Volumen haben, um diese nachzuweisen. Für Neutrinos aus Wechselwirkungen der kosmischen Strahlung im EeV-Bereich mit dem kosmischen Mikrowellenhintergrund wird dennoch nicht mehr als ein Ereignis im Jahr erwartet. Nachweisvolumen in der Größenordnung von 100 km^3 sind notwendig, um den Fluß dieser Neutrinos zu bestimmen und die vorhergesagten Wirkungsquerschnitte zu überprüfen. Alternative Meßtechniken sind erforderlich, um einen Detektor dieses Ausmaßes zu realisieren. Eine vielversprechende Idee ist die Erfassung akustischer Wellen aus den in der Neutrinowechselwirkung erzeugten hadronischen Kaskaden. Aufgrund der höheren Signalstärke und der großen Schalldämpfungslängen ist die Eisdecke des Südpols dem Wasser der Ozeane als Medium vorzuziehen. Zunächst sind jedoch geeignete Sensoren, eine Überprüfung der thermo-akustischen Schallerzeugung und Kenntnisse der akustischen Eigenschaften des Eises von Nöten. In einer theoretischen Ableitung konnte die Äquivalenz der Mechanismen der Erzeugung akustischer Wellen durch thermo-elastische Anregung in Flüßigkeiten und isotropen Festkörpern gezeigt werden. Einer Analyse des existierenden Wissensstandes folgte die Simulation eines kombinierten Cherenkov-Radiowellen-Ultraschall-Detektors. Für den Einsatz im Eis wurden spezielle akustische Sensoren entwickelt und zur Erfassung der Schallemission von intensiven Protonen- und Laserstrahlen eingesetzt. Darauf aufbauend wurde ein akustische Sender- und Empfänger-Aufbau entwickelt, mit dem Ziel, die Ultraschalleigenschaften des südpolaren Eises in-situ zu untersuchen. Die Ergebnisse dieser ersten Bemühungen werden in dieser Arbeit vorgestellt. / Current neutrino telescopes are designed to detect neutrinos with energies in the TeV range. Due to the low fluxes and small cross sections, no high energy neutrinos of extraterrestrial origin have been observed so far. Only the Cherenkov neutrino detectors on the km^3 scale that are currently under construction will have the necessary volume to observe these rare interactions. Yet, for neutrinos from interactions of the ultra-high energy cosmic at EeV energies rays with the ambient cosmic microwave background, event rates of only one per year are expected. To measure the flux and verify the predicted cross sections of these cosmogenic neutrinos, an observed volume of around 100 km^3 will be necessary, that will not be feasible with existing detection techniques. Alternative methods are required to build a detector on these scales. One promising idea is to record the acoustic waves generated in cascades following the neutrino interaction. Higher amplitudes of the sonic signal and the large absorption length of sound favour South Polar ice instead of sea water as a medium. For an estimate of the potential of such a detector, suitable acoustic sensors, a verification of the model of thermo-acoustic sound generation and a determination of the acoustic properties of the ice are necessary. In a theoretical derivation the mechanism of thermo-elastic excitation of acoustic waves was shown to be equivalent for isotropic solids and liquids. A detailed analysis of the existing knowledge and a simulation study of a hybrid optical-radio-acoustic detector have been performed. Ultrasonic sensors dedicated to in-ice application were developed and have been used to record acoustic signals from intense proton and laser beams. Based on this, the hitherto largest array of acoustic sensors and transmitters was devised and implemented, with the aim to study the ultrasonic properties of the South Polar ice in-situ. Results from all of these first efforts are presented.

Os centros de pesquisa não podem simplesmente ignorar que no desenvolvimento de suas atividades, também são geradas quantidade significativas de resíduos. Essa postura é contrária ao papel desempenhado por eles dentro da sociedade, pois devem desenvolver pesquisa com respeito ao meio ambiente. Assim, o presente trabalho teve como objetivo estabelecer um plano de gestão dos resíduos gerados na APTA Pólo Centro Sul. Para isso, levantamentos prévios envolvendo a caracterização dos resíduos ativos e passivos, bem como das fontes geradoras, contribuíram para nortear as ações adotadas, com destaque para a implantação de propostas de segregação, tratamento ou reaproveitamento, englobando resíduos químicos laboratoriais, fitossanitários e sólidos domiciliares. O inventário do passivo relacionado aos produtos fitossanitários resultou em uma lista com 104 ingredientes ativos, dentre os quais, 16 com proposta de banimento, restrições ao uso ou proibidos armazenados em condições inapropriadas. Além disso, 55% da quantidade total era representada por produtos vencidos. Esse inventário foi a base para a construção de um novo depósito para o armazenamento desses produtos. Com o inventário do ativo relacionado aos resíduos químicos laboratoriais, foi verificado que são gerados efluentes contendo metais como cromo e cobre, além de soluções ácidas ou alcalinas. A técnica de precipitação química empregada para a remoção dos metais conferiu aos tratamentos eficiências superiores a 99,9%, permitindo atender a resolução CONAMA 357/2005 a um baixo custo de tratamento. Em relação ao Programa de Coleta Seletiva, o mesmo obteve resultados satisfatórios. Sua implementação iniciou-se com a aplicação de um questionário estruturado voltado a toda comunidade da APTA-PCS e contou com um índice de participação de 91%. Em relação ao diagnóstico dos resíduos são produzidos, em média, 6,8 kg dia-1, representando uma produção per capita diária de 151,3 g. A maior fração de resíduos, em % por peso, está relacionada aos resíduos orgânicos. A organização de um evento voltado a Educação Ambiental contou com a presença de mais de 50 participantes, os quais avaliaram o encontro como ótimo (80%). Os indicadores utilizados para avaliar o Programa de Coleta Seletiva demonstraram que houve uma redução na geração total e per capita de resíduos de 42% e 57%, respectivamente. Além disso, a geração de papel foi reduzida em 57% e, a substituição de copos descartáveis por canecas duráveis recebeu adesão de todos da comunidade. Dentro do Programa de Gerenciamento de Resíduos Químicos (PGRQ), também foi implantado um sistema de obtenção de água desionizada, o qual apresentou capacidade de produção de aproximadamente 7.200 L de água com baixa condutividade (0,9 \'mü\'S cm-1). Os resultados alcançados na APTA-PCS são promissores e demonstram que o PGRQ proporcionou ganho ambiental imensurável. Por fim, destaca-se a importância do apoio permanente por parte da Diretoria da APTA-PCS para a manutenção e constante aprimoramento do PGRQ / The research centers simply cannot dissemble that in the development of their activities are also generated significant amounts of wastes. This attitude is contrary to the role played by them in society, as they must do research with respect to the environment. Thus, this study aimed to establish a plan for waste management generated in the APTA Center South Pole. Therefore, previous surveys involving the characterization of active and passive wastes, as well as their sources, contributed to guide the actions taken, mainly for the segregation, recycling or treatment proposals, comprising laboratory chemical waste, pesticides and solid wastes. The passive inventory related to pesticides resulted a list of 104 active ingredients, among which 16 with ban proposal, restrictions or banned, stored in inappropriate conditions. Moreover, 55% was represented by expired products. This inventory was the basis for planning a new warehouse for the storage of these products. In the active inventory related to laboratory chemical wastes was observed the generation of wastes containing metals such as chromium and copper, and acid or alkaline solutions. The chemical precipitation technique employed for removal of metals given to treatment efficiencies exceeding 99.9%, allowing meet the limits established by CONAMA Resolution n° 357/2005 at a low treatment cost. The results of the Waste Collection Program were also satisfactory. Its implementation began with the application of a structured questionnaire to the APTA Center South Pole community, which had a participation rate of 91%. The waste diagnosis showed that are produced 6.8 kg day-1 on average of solid wastes, representing a daily per capita production of 151.3 g. The largest waste fraction, in % by weight, is related to organic wastes. An Environmental Education event was attended by over 50 participants, who evaluated it as excellent (80%). The indicators used to evaluate the program demonstrated that there was a reduction in total waste generation of 42% and 57% per capita and, the replacement of one-way plastic drinking cups for mugs received adherence of all the community. Moreover, the paper generation and the consumption of disposable products were reduced by 57% and 100%, respectively. Within the Program, a system for producing deionized water was also developed, which had a production capacity of approximately 7200 L of water with excellent quality (0.9\'mü\'S cm-1). The achievements of the WMP are promising and demonstrate that it has provided immeasurable environmental gain. Finally, it stands out the importance of continuous support by APTA Center South Pole board for the maintenance and constant improvement of the WMP

Os centros de pesquisa não podem simplesmente ignorar que no desenvolvimento de suas atividades, também são geradas quantidade significativas de resíduos. Essa postura é contrária ao papel desempenhado por eles dentro da sociedade, pois devem desenvolver pesquisa com respeito ao meio ambiente. Assim, o presente trabalho teve como objetivo estabelecer um plano de gestão dos resíduos gerados na APTA Pólo Centro Sul. Para isso, levantamentos prévios envolvendo a caracterização dos resíduos ativos e passivos, bem como das fontes geradoras, contribuíram para nortear as ações adotadas, com destaque para a implantação de propostas de segregação, tratamento ou reaproveitamento, englobando resíduos químicos laboratoriais, fitossanitários e sólidos domiciliares. O inventário do passivo relacionado aos produtos fitossanitários resultou em uma lista com 104 ingredientes ativos, dentre os quais, 16 com proposta de banimento, restrições ao uso ou proibidos armazenados em condições inapropriadas. Além disso, 55% da quantidade total era representada por produtos vencidos. Esse inventário foi a base para a construção de um novo depósito para o armazenamento desses produtos. Com o inventário do ativo relacionado aos resíduos químicos laboratoriais, foi verificado que são gerados efluentes contendo metais como cromo e cobre, além de soluções ácidas ou alcalinas. A técnica de precipitação química empregada para a remoção dos metais conferiu aos tratamentos eficiências superiores a 99,9%, permitindo atender a resolução CONAMA 357/2005 a um baixo custo de tratamento. Em relação ao Programa de Coleta Seletiva, o mesmo obteve resultados satisfatórios. Sua implementação iniciou-se com a aplicação de um questionário estruturado voltado a toda comunidade da APTA-PCS e contou com um índice de participação de 91%. Em relação ao diagnóstico dos resíduos são produzidos, em média, 6,8 kg dia-1, representando uma produção per capita diária de 151,3 g. A maior fração de resíduos, em % por peso, está relacionada aos resíduos orgânicos. A organização de um evento voltado a Educação Ambiental contou com a presença de mais de 50 participantes, os quais avaliaram o encontro como ótimo (80%). Os indicadores utilizados para avaliar o Programa de Coleta Seletiva demonstraram que houve uma redução na geração total e per capita de resíduos de 42% e 57%, respectivamente. Além disso, a geração de papel foi reduzida em 57% e, a substituição de copos descartáveis por canecas duráveis recebeu adesão de todos da comunidade. Dentro do Programa de Gerenciamento de Resíduos Químicos (PGRQ), também foi implantado um sistema de obtenção de água desionizada, o qual apresentou capacidade de produção de aproximadamente 7.200 L de água com baixa condutividade (0,9 \'mü\'S cm-1). Os resultados alcançados na APTA-PCS são promissores e demonstram que o PGRQ proporcionou ganho ambiental imensurável. Por fim, destaca-se a importância do apoio permanente por parte da Diretoria da APTA-PCS para a manutenção e constante aprimoramento do PGRQ / The research centers simply cannot dissemble that in the development of their activities are also generated significant amounts of wastes. This attitude is contrary to the role played by them in society, as they must do research with respect to the environment. Thus, this study aimed to establish a plan for waste management generated in the APTA Center South Pole. Therefore, previous surveys involving the characterization of active and passive wastes, as well as their sources, contributed to guide the actions taken, mainly for the segregation, recycling or treatment proposals, comprising laboratory chemical waste, pesticides and solid wastes. The passive inventory related to pesticides resulted a list of 104 active ingredients, among which 16 with ban proposal, restrictions or banned, stored in inappropriate conditions. Moreover, 55% was represented by expired products. This inventory was the basis for planning a new warehouse for the storage of these products. In the active inventory related to laboratory chemical wastes was observed the generation of wastes containing metals such as chromium and copper, and acid or alkaline solutions. The chemical precipitation technique employed for removal of metals given to treatment efficiencies exceeding 99.9%, allowing meet the limits established by CONAMA Resolution n° 357/2005 at a low treatment cost. The results of the Waste Collection Program were also satisfactory. Its implementation began with the application of a structured questionnaire to the APTA Center South Pole community, which had a participation rate of 91%. The waste diagnosis showed that are produced 6.8 kg day-1 on average of solid wastes, representing a daily per capita production of 151.3 g. The largest waste fraction, in % by weight, is related to organic wastes. An Environmental Education event was attended by over 50 participants, who evaluated it as excellent (80%). The indicators used to evaluate the program demonstrated that there was a reduction in total waste generation of 42% and 57% per capita and, the replacement of one-way plastic drinking cups for mugs received adherence of all the community. Moreover, the paper generation and the consumption of disposable products were reduced by 57% and 100%, respectively. Within the Program, a system for producing deionized water was also developed, which had a production capacity of approximately 7200 L of water with excellent quality (0.9\'mü\'S cm-1). The achievements of the WMP are promising and demonstrate that it has provided immeasurable environmental gain. Finally, it stands out the importance of continuous support by APTA Center South Pole board for the maintenance and constant improvement of the WMP

This thesis presents new information about the global megaregolith of the Moon, using 2059 craters (5 to 50 km diameter) as natural probes. Iron (FeO) and titanium (TiO2) concentrations were obtained from crater ejecta blanket data over an area between 600 North to 600 South latitude derived from the 1994 Clementine mission. The average iron and titanium weight percentages for lunar crater ejecta were calculated using the US Geological Survey's ISIS software, and used to determine the variation with depth of iron (FeO) and titanium (TiO2) in the highlands, mare areas and the South Pole Aitken basin. In addition, megaregolith compositional Iron (FeO) and Titanium (TiO2) Maps and compositional Province Maps were generated, and studied in detail. The Lunar Megaregolith Iron Province Map divides the Highland areas into 2 distinct provinces of low-iron Highland I (0-3.7 FeO weight percentage) and low-medium level iron Highland II (3.8-6.4%), and the Mare and South Pole Aitken Basin each into 3 distinct provinces (6.5-9.7%, 9.8-13.6%, and 13.7-18.3%). Similarly, a Titanium Megaregolith Province Map divides the Moon globally into 5 provinces based on weight percentages of TiO2. A new finding is the Highland II Province of elevated iron concentration which surrounds basins. These elevated iron levels may be explained in terms of an "Intrusion Model". In this model, basin formation fractures the surrounding anorthositic bedrock, and the middle level anorthositic crust allows mafic (basaltic?) magma to intrude. This intrusion into the megaregolith is in the form of sills and dykes from deep mafic sources but generally does not intrude into the surface regolith. In some places however, the mafic (basaltic?) lava may have extruded onto the surface, such as near Crater 846 (15.6N 92.2W). The megaregolith, which consists of large volume breccia, would have voids and vacancies in this structure into which mafic or basaltic material could intrude. "Islands" of Highland I Province material surrounded by Highland II Province indicate this intrusion was non-uniform. Another possible explanation for the Highland II Province iron levels comes from the "Thrust Block" model, where deep mafic material has been broken into large blocks by the basin-forming events, and "thrusted" or uplifted to displace most of the overlying anorthosite bedrock, thereby mechanically mixing with the megaregolith to provide the additional iron input. However, this does entirely fit comfortably with the data in this study. A third explanation for the Highland II Province arises from the "Basin Impact Ejecta Model" such as the Imbrium Impact described by Haskin (1998). The Basin Impact Ejecta model describes the effect of basin impacts around 4.0 billion to 3.8 billion years ago in the Moon's history (Ryder, 1990; Taylor, 2001)). This model implies that basin material was ejected and deposited on a global or similar scale. However, the results of this study place severe limitations on the feasibility of the "Basin Impact Ejecta" model to explain any significant mafic input from such ejecta in forming the Highland II megaregolith material. These Province Maps provide a new dimension to the study of the Moon's crustal development and reveal a highly complex history, providing a basis for future study.

<p>The <em>IceCube telescope</em> is built within the ice at the geographical South Pole in the middle of the Antarctica continent. The purpose of the telescope is to detect muon neutrinos, the muon neutrino being an elementary particle with minuscule mass coming from space.</p><p>The detector consists of some 5000 DOMs registering photon hits (light). A muon neutrino traveling through the detector might give rise to a track of photons making up a straight line, and by analyzing the hit output of the DOMs, looking for tracks, neutrinos and their direction can be detected.</p><p>When processing the output, triggers are used. Triggers are calculation- efficient algorithms used to tell if the hits seem to make up a track - if that is the case, all hits are processed more carefully to find the direction and other properties of the track.</p><p>The Track Engine is an additional trigger, specialized to trigger on low- energy events (few track hits), which are particularly difficult to detect. Low-energy events are of special interest in the search for Dark Matter.</p><p>An algorithm for triggering on low-energy events has been suggested. Its main idea is to divide time in overlapping time windows, find all possible pairs of hits in each time window, calculate the spherical coordinates θ and ϕ of the position vectors of the hits of the pairs, histogram the angles, and look for peaks in the resulting 2d-histogram. Such peaks would indicate a straight line of hits, and, hence, a track.</p><p>It is not believed that a software implementation of the algorithm would be fast enough. The Master's Thesis project has had the aim of developing an FPGA implementation of the algorithm.</p><p>Such an FPGA implementation has been developed. Extensive tests on the design has yielded positive results showing that it is fully functional. The design can be synthesized to about 180 MHz, making it possible to handle an incoming hit rate of about 6 MHz, giving a margin of more than twice to the expected average hit rate of 2.6 MHz.</p>

The IceCube telescope is built within the ice at the geographical South Pole in the middle of the Antarctica continent. The purpose of the telescope is to detect muon neutrinos, the muon neutrino being an elementary particle with minuscule mass coming from space. The detector consists of some 5000 DOMs registering photon hits (light). A muon neutrino traveling through the detector might give rise to a track of photons making up a straight line, and by analyzing the hit output of the DOMs, looking for tracks, neutrinos and their direction can be detected. When processing the output, triggers are used. Triggers are calculation- efficient algorithms used to tell if the hits seem to make up a track - if that is the case, all hits are processed more carefully to find the direction and other properties of the track. The Track Engine is an additional trigger, specialized to trigger on low- energy events (few track hits), which are particularly difficult to detect. Low-energy events are of special interest in the search for Dark Matter. An algorithm for triggering on low-energy events has been suggested. Its main idea is to divide time in overlapping time windows, find all possible pairs of hits in each time window, calculate the spherical coordinates θ and ϕ of the position vectors of the hits of the pairs, histogram the angles, and look for peaks in the resulting 2d-histogram. Such peaks would indicate a straight line of hits, and, hence, a track. It is not believed that a software implementation of the algorithm would be fast enough. The Master's Thesis project has had the aim of developing an FPGA implementation of the algorithm. Such an FPGA implementation has been developed. Extensive tests on the design has yielded positive results showing that it is fully functional. The design can be synthesized to about 180 MHz, making it possible to handle an incoming hit rate of about 6 MHz, giving a margin of more than twice to the expected average hit rate of 2.6 MHz.

The IceCube neutrino observatory is located in the deep glacial ice below the South Pole. IceCube consists of over 5, 000 photomultiplier tubes regularly spaced throughout a cubic kilometre volume of ice. The photomultiplier tubes are receptive to the light produced by high energy neutrino interactions. As a means of evaluating our understanding of the physics of light propagation, a comparison was made between the data taken from artificial light sources and Monte Carlo simulations of these events. The evaluation was done by comparing the shape of the light arrival-time distributions. The three icemodels compared were the Additionally Heterogeneous Absorption (AHA), South Pole Ice - 1 (Spice) and South Pole Ice - Mie (Spice Mie). The artificial light sources used are LEDs, known as flashers, located within each of the detector modules. The data set used in this study was taken on string 63 with single- photoelectron settings (one LED). Various orientations of the flashing LED and relative position of the light source in the detector, were studied over 15 depths in instrumented ice. Through a χ2 comparison and distribution characteristics it was found that for the majority of cases, simulations which used the Spice Mie ice model matched the data best. There were, however, some isolated cases in which simulations using the Spice 1 or AHA ice models matched the flasher data best.

The IceCube Neutrino Telescope is designed to detect high energy neutrinos with a large array of photomultiplier tubes placed deep within the Antarctic ice. The way that light propagates through the ice needs to be modelled accurately to enable the paths of charged particles to be reconstructed from the distribution of their Cerenkov radiation. Light travelling through even the purest of ice will undergo scattering and absorption processes, however the ice in which IceCube is embedded has optical properties that vary significantly with depth which need to be accurately modelled. Currently, simulation of the muon background using the current ice model is unable to fully replicate experimental data. In this thesis we investigate a potential method of improving on the current generation of ice models. We introduce thin, highly absorbing layers into the current description of the detection medium and investigate the effect on the simulation of muon tracks in IceCube. We find that better agreement between simulation and data can be seen in the occupancy of optical modules, through the introduction of such absorptive layers into the existing ice layers.