No description available.

No description available.

This thesis describes several aspects of cosmic ray composition studies using the Utah Fly's Eye and High Resolution Fly's Eye (HiRes) detectors. The Fly's Eye detector utilises the atmospheric fluorescence technique to measure the development of cosmic ray cascades as they pass through the atmosphere. This is complementary to the surface array technique, as used by the Akeno experiment in Japan, which measures the electromagnetic and muon content of air showers at a single observation level. For some time it was thought that Fly's Eye and Akeno gave inconsistent composition results. In Chapter 4 I show that the inconsistency is due, for the most part, to a difference in the assumptions made about hadronic interactions. In Chapter 5 I present analysis of the composition between 10^17 and 10^18 eV using the prototype High Resolution Fly's Eye (HiRes) detector in coincidence with the Michigan Muon Array (MIA). The hybrid nature of these measurements gives us more information about cosmic ray showers than either technique on its own. The consistency or otherwise of the composition measured by the two detectors is discussed. Finally, in Chapter 6, I discuss a method of extracting the total proton-proton cross section from the cosmic ray data. This information is of interest because it is derived at centre of mass energies much higher (by at least an order of magnitude) than those currently accessible by collider experiments. I present a preliminary calculation of the cross section using the HiRes/MIA hybrid data set. / Thesis (Ph.D.)--Department of Physics and Mathematical Physics, 2001.

<p>The purpose with this examination is to build a measureequipment to AerotechTelub AB (AT), who will registrate fault in SRAM-memory in contact with cosmic radiation. The equipment will be created around developcard from Memec Design with FPGA from Xilinx. The logic in the FPGA will be implemented with the hardwaredescribed language VHDL. The SRAM-memory that will be tested is build in CMOS-teknologi. The memorycells will be loaded with a predecided bitpattern. Changes in the memorycells will be registrated together with the adress where the fault came up. </p><p>The equipment will be used of AT at the measuring they use to do in special laboratories that can give cosmic radiation.</p>

The purpose with this examination is to build a measureequipment to AerotechTelub AB (AT), who will registrate fault in SRAM-memory in contact with cosmic radiation. The equipment will be created around developcard from Memec Design with FPGA from Xilinx. The logic in the FPGA will be implemented with the hardwaredescribed language VHDL. The SRAM-memory that will be tested is build in CMOS-teknologi. The memorycells will be loaded with a predecided bitpattern. Changes in the memorycells will be registrated together with the adress where the fault came up. The equipment will be used of AT at the measuring they use to do in special laboratories that can give cosmic radiation.

This thesis describes several aspects of cosmic ray composition studies using the Utah Fly's Eye and High Resolution Fly's Eye (HiRes) detectors. The Fly's Eye detector utilises the atmospheric fluorescence technique to measure the development of cosmic ray cascades as they pass through the atmosphere. This is complementary to the surface array technique, as used by the Akeno experiment in Japan, which measures the electromagnetic and muon content of air showers at a single observation level. For some time it was thought that Fly's Eye and Akeno gave inconsistent composition results. In Chapter 4 I show that the inconsistency is due, for the most part, to a difference in the assumptions made about hadronic interactions. In Chapter 5 I present analysis of the composition between 10^17 and 10^18 eV using the prototype High Resolution Fly's Eye (HiRes) detector in coincidence with the Michigan Muon Array (MIA). The hybrid nature of these measurements gives us more information about cosmic ray showers than either technique on its own. The consistency or otherwise of the composition measured by the two detectors is discussed. Finally, in Chapter 6, I discuss a method of extracting the total proton-proton cross section from the cosmic ray data. This information is of interest because it is derived at centre of mass energies much higher (by at least an order of magnitude) than those currently accessible by collider experiments. I present a preliminary calculation of the cross section using the HiRes/MIA hybrid data set. / Thesis (Ph.D.)--Department of Physics and Mathematical Physics, 2001.

No description available.

Neste trabalho, cujo objetivo foi fornecer subsídios que permitam estabelecer um sistema de dosimetria para as tripulações de aeronaves que operam no território nacional, foi desenvolvida uma técnica para realizar medições do equivalente de dose ambiente em aeronaves. Foi testado um detector ativo, para uso embarcado em aeronaves, avaliando-se sua adequação a este tipo específico de medição, assim como sua suscetibilidade às interferências magnética e eletromagnética. O equipamento foi calibrado em campos metrologicamente rastreados e foi verificado em um campo especial do laboratório europeu CERN, que reproduz com grande proximidade o espectro de partículas existentes em altitudes de voo de aeronaves, sendo a seguir testado em diversos ensaios em voo, em uma aeronave da Força Aérea Brasileira. Os resultados foram avaliados e comparados com aqueles obtidos por diversos programas computacionais de estimativa de dose oriunda de radiação cósmica, com respeito à sua adequação para uso na região da América do Sul e foi selecionado o programa CARI-6 para avaliar as doses efetivas médias estimadas a que estão sujeitas as tripulações que operam nesta região. Foi efetuada uma avaliação estatística da distribuição de doses efetivas das tripulações dos voos que operam na região da América do Sul e Caribe e concluiu-se que grande parte destas tripulações estão sujeitas a doses efetivas anuais que ultrapassam o limite estabelecido para membros do público. Adicionalmente, foi proposto um dosímetro passivo preliminar, baseado em detectores termoluminescentes, e foram ainda estabelecidas colaborações internacionais com grupos de pesquisa do Reino Unido e da Itália, para a realização de medições conjuntas do equivalente de dose ambiente em aeronaves. / The objective of this work is the establishment of a dosimetric system for the aircrew in the domestic territory. A technique to perform measurements of ambient dose equivalent in aircrafts was developed. An active detector was evaluated for onboard aircraft use, testing its adequacy to this specific type of measurement as well as its susceptibility to the magnetic and electromagnetic interferences. The equipment was calibrated in standard radiation beams and in a special field of the European Laboratory CERN, that reproduces with great proximity the real spectrum in aircraft flight altitudes; it was also tested in several flights, in an Brazilian Air Force\'s aircraft. The results were evaluated and compared with those obtained from several computational programs for cosmic radiation estimatives, with respect to its adequacy for use in the South American region. The program CARI-6 was selected to evaluate the estimated averaged effective doses for the aircrew who operate in this region. A statistical distribution of aircrew effective doses in South America and Caribe was made, and the results show that a great part of this aircrew members are subjected to annual effective doses that exceed the dose limits for the members of the public. Additionally, a preliminary passive dosemeter, based in thermoluminescent detectors, was proposed; international collaborations with United Kingdom and Italy were established for joint measurements of the ambient equivalent doses in aircrafts.

No description available.

New measurements of the antiproton flux and the antiproton-to-proton flux ratio at the top of the atmosphere between 80 MeV and 2.0 GeV are presented. The measurement was conducted from July 2006 to March 2008 with the PAMELA satellite experiment. This is a period of minimum solar activity and negative solar polarity and the PAMELA measurement is the first observation of antiprotons during this particular solar state. The PAMELA instrument comprises a permanent magnet spectrometer, a scintillator based time-of-flight system, an electromagnetic calorimeter and an anticoincidence shield. These detectors can identify antiprotons from a background of cosmic-ray electrons and locally produced pions. The PAMELA instrument is mounted on the Resurs DK1 satellite that was launched from the Baikonur Cosmodrome on June the 15th into a semi-polar orbit with an inclination of 70o. During approximately 500 days of data collection 170 antiprotons were identified. The derived antiproton spectrum shows a steep increase up to 2 GeV as expected for pure secondary production of galactic antiprotons. The antiproton flux is over-estimated by most current models of secondary production compared to PAMELA results. There are no indications of the excess of antiprotons at low energy predicted by theories of primordial black hole evaporation. The antiproton-to-proton flux ratio is in agreement with drift models of solar modulation, which are also favoured by recent PAMELA measurements of the positron fraction. / QC 20100811