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Development of a biokinetic-dosimetric model for '2'1'0Pb and '2'1'0Po based on alpha spectroscopic measurements of '2'1'0Po in bone : methodological issues and biological implicationsSalmon, Philip Linley January 1998 (has links)
No description available.
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Development of a Transmission-type Ultra-thin ScCVD Diamond ∆E Detector for Alpha ParticlesCheng, Xingzhi January 2020 (has links)
We present an ultra-thin transmission-type radiation detector developed for counting microbeam alpha particles. The ∆E alpha detector is a single crystal chemical vapor deposited diamond (ScCVDD) and will be installed between the microbeam accelerator window and a biologic sample. The commercially available optical grade ScCVDD sample (3 mm × 3 mm × 50 µm) was etched down to a few µm thickness which allows alpha particles to penetrate, and then it was followed by the surface cleaning, electrical contact deposition and post-metallization annealing. SRIM code and MCNP6 were used for energy loss calculation of alpha particles in electrodes and diamond and pulse height spectra prediction. In order to evaluate the performance of the ultra-thin ScCVDD detector, a ∆E-E detectors system was setup using a calibration source, the ScCVD detector and a silicon surface barrier detector (SBD). The absolute and intrinsic totally efficiency were determined as 0.3 % and 16 % respectively. Alpha and gamma peaks were observed while the peak resolution is not quite promised. The transmission ability of the ScCVDD detector was verified by applying coincidence operation with 0.22 µs time window. The thickness of the ultra-thin diamond sample was reassessed to be 8.315±0.690 µm from ∆E-E spectrometery. / Thesis / Master of Science (MSc)
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X-Ray Emission Analysis Using Radioisotopic Alpha-Particle ExcitationRobertson, Robert 09 1900 (has links)
<p> The combined capabilities of alpha-particle emitting isotopic excitation sources and modern semiconductor detectors are investigated with a view to extending the light-element range of radioisotope-based X-ray emission analysis.</p> <p> The construction and performance of a windowless low-energy X-ray spectrometer designed around a lithium-drifted
silicon detector and a 210Po source are discussed. It is shown that under the conditions used low-energy X-ray emission and detection are greatly favoured.</p> <p> Measurements of relative cross-sections for the production of X-rays by ~5.2 MeV alpha-particles in elements
from oxygen to iron are reported. The results for elements of Z>16 are in good agreement with those predicted from the scaling of equal velocity proton values but show large positive
deviations for elements of Z<16.</p> <p> Investigative applications of the spectrometer to
quantitative analyses of blast-furnace slags, iron ores and silicate rocks for oxygen, silicon, sulpher, calcium and iron are described.</p> <p> The future prospects of radioisotopic alpha-particle X-ray excitation methods are surveyed.</p> / Thesis / Doctor of Philosophy (PhD)
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Analysis and Calibration of the MER-A APXS Alpha Particle Backscatter SpectraVanBommel, Scott 28 March 2013 (has links)
The Alpha Particle X-ray Spectrometer (APXS) on the Mars Exploration Rovers possesses the ability to detect carbon and oxygen within martian samples via Rutherford backscattering principles. Several consecutive measurements of the martian atmosphere by Spirit, paralleled by Monte Carlo simulations, provided an energy calibration to mitigate the absence of an alpha-mode calibration pre-flight. Data from a pre-flight thermal acceptance test agreed with this energy calibration, confirming the presence of an unexpected offset. Correcting a bug in the APXS firmware resulted in a temperature-independent energy scale. A model was developed and applied to all atmospheric data illustrating a dip in atmospheric peak areas, potentially arising from a week-long weather event on Mars. An early expansion of this model to solid samples has not yet been able to detect any hydrated minerals or carbonates. Preliminary investigations into determining martian atmospheric pressure and potential elemental layering within samples shows promise.
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Radon exhalation of building materialsWentzel, Farrel Sidney January 2018 (has links)
>Magister Scientiae - MSc / Public concern about all radiation and radon exhalation from building
materials has been highlighted recently. The purpose of this study is
to address this public concern and to investigate the contribution of
building materials to indoor radon levels. As in soil and rocks, radon
gas is formed inside the building materials by decay of the parent
nuclide 226Ra. It is not possible to determine the radon exhalation rate
simply from the activity concentration of 226Ra, instead one must
measure radon exhalation rates directly from the surface of the
material. 222Rn has been identified as an important factor that could
result in a health hazard by studies all around the world.
The exhalation experiments were done at the UWC physics
department, in the Nuclear Physics Lab. A RAD7 radon detector was
used to measure the radon concentration in an air tight chamber that
contained various building material samples. The RAD7 records the
number of alpha particles with energy of 6.11 MeV which results from
the decay of 218Po, the daughter of 222Rn. The RAD7 detector converts
counts into Becquerel’s per cubic metre (Bq/m3). The building
materials tested were the raw materials used in construction such as
two different types of building sand, building stones, coarse
aggregate, floor and roof tiles, various granites from across the world
that were sourced locally and uranium bearing sandstone originating
from a Beaufort-West prospecting site. Stones from this site were
used as filler material in the construction of two farm houses. Most
building materials were found to have a very low rate of radon
exhalation. The only materials that had any significant radon
exhalation were 2 granite samples with a maximum exhalation rate of
1.5 Bq.m-2.h-1 and the uranium bearing sandstone. It is safe to say that
the overwhelming majority of building materials tested are safe to use
but some granites may require further study. The uranium bearing
sandstone is a definite radiation protection issue and should not be
used in any construction.
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Energetic ion losses in high-beta rippled tokamaks / リップルトカマクにおける高エネルギー粒子損失に関する研究Bunno, Michinao 24 March 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(エネルギー科学) / 甲第18383号 / エネ博第295号 / 新制||エネ||61(附属図書館) / 31241 / 京都大学大学院エネルギー科学研究科エネルギー基礎科学専攻 / (主査)教授 中村 祐司, 教授 岸本 泰明, 教授 前川 孝 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM
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Fabrication, characterization and simulation of 4H-SiC Schottky diode alpha particle detectors for pyroprocessing actinide monitoringGarcia, Timothy Richard 21 May 2014 (has links)
No description available.
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Vztah obsahu helia ve slunečním větru k procesům na Slunci / Relationship of helium abundance in the solar wind to solar activityCagaš, Petr January 2015 (has links)
Rapid changes in relative helium abundance in solar wind are often attributed to the flux tube crossings - thus between solar wind streams coming from different parts of the solar corona. Recent studies however show, that the changes in relative helium abundance are not always correlated with changes in other parameters and therefore the relative helium abundance could be changed even during the propagation of solar wind inside a flux tube. The topic of this thesis is an analysis of rapid changes of solar wind parameters and their mutual connection. Using a multipoint (we use data from the SPEKTR-R, WIND and the THEMIS spacecraft) case study of interplanetary shocks, we show that a possible explanation of those changes could be a magnetosonic instability excited by the differential flow between helium and proton populations.
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Design and Development of Peptidomimetic Ligands for Targeting Radiopharmaceuticals, Imaging Probes, and Immunotherapeutics in Oncologic DiseaseDoligalski, Michael Lawrence 21 October 2016 (has links)
Cancer is a leading cause of morbidity and mortality in the developed world. While much has been learned about these diseases in the last few decades, one of the main barriers to widespread advancement is the heterogeneity of cancer biology. A growing body of evidence supports the idea that certain protein receptors are overexpressed on the surface of tumor cells as compared to normal tissues. These extracellular biomarkers provide a unique opportunity to selectively target the tumor with both imaging and therapeutic modalities. The research in this dissertation focuses on targeting proteins on the tumor cell surface with peptidomimetic ligands.
Following a description of various extracellular receptors, chapter one discusses targeting ligands designed to specifically and selectively bind these receptors. It reviews recent literature on targeted alpha-particle therapy and ends with an explanation of the advantages of peptide ligands. Three distinct approaches to imaging and therapeutic modalities are then discussed in subsequent chapters. First, a peptide ligand was designed to target radionuclides to malignant melanoma cells in an effort to develop companion radiotherapeutics and diagnostic imaging agents. The second research project describes the synthesis of a novel antagonist peptide ligand with conjugated near infrared dye, and its utility for real-time intraoperative guidance during pancreatic adenocarcinoma resection. Finally, the last chapter describes how the relatively new field of immunomodulatory effectors may be enhanced by their derivatization with peptide targeting ligands.
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Comparison of the measured biodistribution of 212Pb-radiolabeled monoclonal antibodies (Trastuzumab) in mice with 232Th and progeny in human reticuloendothelial tissue measured using alpha particle track autoradiographic microdosimetry from ThorotrastSchneider, Nathaniel R. January 2019 (has links)
No description available.
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