Matching Items (7)

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Implementation of a Prototype Aerogel RICH detector for Testing the Performance of Aerogels

Description

Our group has constructed a ring-imaging Cherenkov (RICH) detector with the goal of testing the performance of aerogel tiles in charged particle detectors. In previous work, tiles produced by Aspen

Our group has constructed a ring-imaging Cherenkov (RICH) detector with the goal of testing the performance of aerogel tiles in charged particle detectors. In previous work, tiles produced by Aspen Aerogels were tested as radiators in Cherenkov threshold counters and compared to commercial-grade samples. As an extension of this work we built a counter of the RICH type, which is used in practice to extract more particle identification information than threshold counters, and we have studied the images resulting from various aerogel samples.
The detector was designed for use in table-top experiments in which our particle source would be cosmic rays. Due to the vast energy range of cosmic rays, the window in which we can discriminate velocities is relatively small. Since the particles we do detect generally have β≈1, the relativistic limit β→1 motivates imaging by the Focusing Aerogel RICH (FARICH) technique, in which photons from multiple tiles are focused together at a detection plane.
Our detection plane is an array of flat-panel, multi-anode photomultiplier tubes (PMTs). Readout consists of multiplexing the anode outputs, recording the digitized signal, and converting this into a matrix of integrated charge values. The charge distribution in that matrix should directly imply the particle's speed; however, in practice, final recorded images are the influenced by many intermediate processes, so we have attempted to make meaningful measurements by averaging over numerous events.
For a given configuration and data collection, we produce the spatial distribution of observed signals relative to the cosmic ray's point of impact. These distributions have the expected form of a ring and their characteristics compare favorably with the predictions of geometric optics. Our confidence in the images is increased by verifying that changes to the configuration are reflected by the changes in the rings. We find that FARICH improves the sharpness of our ring images, but tiles must be used individually for actual aerogel analysis. So far we have shown that the Aspen tiles behave as one would expect for the purposes of RICH. Their images do resemble those produced by commercial-grade tiles, but we do not have tiles sufficiently similar for side-by-side comparison. A method of quantifying tile performance has proven difficult and is the only remaining task for our group.

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  • 2014-05

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Cryptojacking Detection: A Classification and Comparison of Malicious Cryptocurrency Mining Detection Systems

Description

Cryptojacking is a process in which a program utilizes a user’s CPU to mine cryptocurrencies unknown to the user. Since cryptojacking is a relatively new problem and its impact is

Cryptojacking is a process in which a program utilizes a user’s CPU to mine cryptocurrencies unknown to the user. Since cryptojacking is a relatively new problem and its impact is still limited, very little has been done to combat it. Multiple studies have been conducted where a cryptojacking detection system is implemented, but none of these systems have truly solved the problem. This thesis surveys existing studies and provides a classification and evaluation of each detection system with the aim of determining their pros and cons. The result of the evaluation indicates that it might be possible to bypass detection of existing systems by modifying the cryptojacking code. In addition to this classification, I developed an automatic code instrumentation program that replaces specific instructions with functionally similar sequences as a way to show how easy it is to implement simple obfuscation to bypass detection by existing systems.

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  • 2021-05

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Investigation of Star Formation: Instrumentation and Methodology

Description

A thorough exploration of star formation necessitates observation across the electromagnetic spectrum. In particular, observations in the submillimeter and ultra-violet allow one to observe very early stage star formation and

A thorough exploration of star formation necessitates observation across the electromagnetic spectrum. In particular, observations in the submillimeter and ultra-violet allow one to observe very early stage star formation and to trace the evolution from molecular cloud collapse to stellar ignition. Submillimeter observations are essential for piercing the heart of heavily obscured stellar nurseries to observe star formation in its infancy. Ultra-violet observations allow one to observe stars just after they emerge from their surrounding environment, allowing higher energy radiation to escape. To make detailed observations of early stage star formation in both spectral regimes requires state-of-the-art detector technology and instrumentation. In this dissertation, I discuss the calibration and feasibility of detectors developed by Lawrence Berkeley National Laboratory and specially processed at the Jet Propulsion Laboratory to increase their quantum efficiency at far-ultraviolet wavelengths. A cursory treatment of the delta-doping process is presented, followed by a thorough discussion of calibration procedures developed at JPL and in the Laboratory for Astronomical and Space Instrumentation at ASU. Subsequent discussion turns to a novel design for a Modular Imager Cell forming one possible basis for construction of future large focal plane arrays. I then discuss the design, fabrication, and calibration of a sounding rocket imaging system developed using the MIC and these specially processed detectors. Finally, I discuss one scientific application of sub-mm observations. I used data from the Heinrich Hertz Sub-millimeter Telescope and the Sub-Millimeter Array (SMA) to observe sub-millimeter transitions and continuum emission towards AFGL 2591. I tested the use of vibrationally excited HCN emission to probe the protostellar accretion disk structure. I measured vibrationally excited HCN line ratios in order to elucidate the appropriate excitation mechanism. I find collisional excitation to be dominant, showing the emission originates in extremely dense (n&sim10;11 cm-3), warm (T&sim1000; K) gas. Furthermore, from the line profile of the v=(0, 22d, 0) transition, I find evidence for a possible accretion disk.

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Date Created
  • 2012

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Instrument design and radiation pattern testing for terahertz astronomical instruments

Description

The Milky Way galaxy is a powerful dynamic system that is highly efficient at recycling material. Stars are born out of intergalactic gas and dust, fuse light elements into heavier

The Milky Way galaxy is a powerful dynamic system that is highly efficient at recycling material. Stars are born out of intergalactic gas and dust, fuse light elements into heavier elements in their cores, then upon stellar death spread material throughout the galaxy, either by diffusion of planetary nebula or by explosive events for high mass stars, and that gas must cool and condense to form stellar nurseries. Though the stellar lifecycle has been studied in detail, relatively little is known about the processes by which hot, diffuse gas ejected by dying stars cools and conglomerates in the interstellar medium (ISM). Much of this mystery arises because only recently have instruments with sufficient spatial and spectral resolution, sensitivity, and bandwidth become available in the terahertz (THz) frequency spectrum where these clouds peak in either thermal or line emission. In this dissertation, I will demonstrate technology advancement of instruments in this frequency regime with new characterization techniques, machining strategies, and scientific models of the spectral behavior of gas species targeted by these instruments.

I begin this work with a description of radiation pattern measurements and their use in astronomical instrument characterization. I will introduce a novel technique to measure complex (phase-sensitive) field patterns using direct detectors. I successfully demonstrate the technique with a single pixel microwave inductance detectors (MKID) experiment. I expand that work by measuring the APEX MKID (A-MKID) focal plane array of 880 pixel detectors centered at 350 GHz. In both chapters I discuss the development of an analysis pipeline to take advantage of all information provided by complex field mapping. I then discuss the design, simulation, fabrication processes, and characterization of a circular-to-rectangular waveguide transformer module integrated into a circularly symmetric feedhorn block. I conclude with a summary of this work and how to advance these technologies for future ISM studies.

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Date Created
  • 2018

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MEMS harsh environment sensors for earth and space exploration

Description

Harsh environments have conditions that make collecting scientific data difficult with existing commercial-off-the-shelf technology. Micro Electro Mechanical Systems (MEMS) technology is ideally suited for harsh environment characterization and operation due

Harsh environments have conditions that make collecting scientific data difficult with existing commercial-off-the-shelf technology. Micro Electro Mechanical Systems (MEMS) technology is ideally suited for harsh environment characterization and operation due to the wide range of materials available and an incredible array of different sensing techniques while providing small device size, low power consumption, and robustness. There were two main objectives of the research conducted. The first objective was to design, fabricate, and test novel sensors that measure the amount of exposure to ionizing radiation for a wide range of applications including characterization of harsh environments. Two types of MEMS ionizing radiation dosimeters were developed. The first sensor was a passive radiation-sensitive capacitor-antenna design. The antenna's emitted frequency of peak-intensity changed as exposure time to radiation increased. The second sensor was a film bulk acoustic-wave resonator, whose resonant frequency decreased with increasing ionizing radiation exposure time. The second objective was to develop MEMS sensor systems that could be deployed to gather scientific data and to use that data to address the following research question: do temperature and/or conductivity predict the appearance of photosynthetic organisms in hot springs. To this end, temperature and electrical conductivity sensor arrays were designed and fabricated based on mature MEMS technology. Electronic circuits and the software interface to the electronics were developed for field data collection. The sensor arrays utilized in the hot springs yielded results that support the hypothesis that temperature plays a key role in determining where the photosynthetic organisms occur. Additionally, a cold-film fluidic flow sensor was developed, which is suitable for near-boiling temperature measurement. Future research should focus on (1) developing a MEMS pH sensor array with integrated temperature, conductivity, and flow sensors to provide multi-dimensional data for scientific study and (2) finding solutions to biofouling and self-calibration, which affects sensor performance over long-term deployment.

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Created

Date Created
  • 2013

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Planetary Geological Science and Aerospace Systems Engineering Applications of Thermal Infrared Remote Sensing for Earth, Mars, and the Outer Bodies

Description

Many planetary science missions study thermophysical properties of surfaces using infrared spectrometers and infrared cameras. Thermal inertia is a frequently derived thermophysical property that quantifies the ability for heat to

Many planetary science missions study thermophysical properties of surfaces using infrared spectrometers and infrared cameras. Thermal inertia is a frequently derived thermophysical property that quantifies the ability for heat to exchange through planetary surfaces.

To conceptualize thermal inertia, the diffusion equation analogies are extended using a general effusivity term: the square root of a product of conductivity and capacity terms. A hypothetical thermal inductance was investigated for diurnal planetary heating. The hyperbolic heat diffusion equation was solved to derive an augmented thermal inertia. The hypothetical thermal inductance was modeled with negligible effect on Mars.

Extending spectral performance of infrared cameras was desired for colder bodies in the outer solar system where peak infrared emission is at longer wavelengths. The far-infrared response of an infrared microbolometer array with a retrofitted diamond window was determined using an OSIRIS-REx—OTES interferometer. An instrument response function of the diamond interferometer-microbolometer system shows extended peak performance from 15 µm out to 20 µm and 40% performance to at least 30 µm. The results are folded into E-THEMIS for the NASA flagship mission: Europa Clipper.

Infrared camera systems are desired for the expanding smallsat community that can inherit risk and relax performance requirements. The Thermal-camera for Exploration, Science, and Imaging Spacecraft (THESIS) was developed for the Prox-1 microsat mission. THESIS, incorporating 2001 Mars Odyssey—THEMIS experience, consists of an infrared camera, a visible camera, and an instrument computer. THESIS was planned to provide images for demonstrating autonomous proximity operations between two spacecraft, verifying deployment of the Planetary Society’s LightSail-B, and conducting remote sensing of Earth. Prox-1—THESIS was selected as the finalist for the competed University Nanosatellite Program-7 and was awarded a launch on the maiden commercial SpaceX Falcon Heavy. THESIS captures 8-12 µm IR images with 100 mm optics and RGB color images with 25 mm optics. The instrument computer was capable of instrument commanding, automatic data processing, image storage, and telemetry recording. The completed THESIS has a mass of 2.04 kg, a combined volume of 3U, and uses 7W of power. THESIS was designed, fabricated, integrated, and tested in ASU’s 100K clean lab.

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Created

Date Created
  • 2018

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Utilization of thermoplastic mounting studs for simple performance testing on hot mix asphalt

Description

The objective of the research is to test the use of 3D printed thermoplastic to produce fixtures which affix instrumentation to asphalt concrete samples used for Simple Performance Testing (SPT).

The objective of the research is to test the use of 3D printed thermoplastic to produce fixtures which affix instrumentation to asphalt concrete samples used for Simple Performance Testing (SPT). The testing is done as part of materials characterization to obtain properties that will help in future pavement designs. Currently, these fixtures (mounting studs) are made of expensive brass and cumbersome to clean with or without chemicals.

Three types of thermoplastics were utilized to assess the effect of temperature and applied stress on the performance of the 3D printed studs. Asphalt concrete samples fitted with thermoplastic studs were tested according to AASHTO & ASTM standards. The thermoplastics tested are: Polylactic acid (PLA), the most common 3D printing material; Acrylonitrile Butadiene Styrene (ABS), a typical 3D printing material which is less rigid than PLA and has a higher melting temperature; Polycarbonate (PC), a strong, high temperature 3D printing material.

A high traffic volume Marshal mix design from the City of Phoenix was obtained and adapted to a Superpave mix design methodology. The mix design is dense-graded with nominal maximum aggregate size of ¾” inch and a PG 70-10 binder. Samples were fabricated and the following tests were performed: Dynamic Modulus |E*| conducted at five temperatures and six frequencies; Flow Number conducted at a high temperature of 50°C, and axial cyclic fatigue test at a moderate temperature of 18°C.

The results from SPT for each 3D printed material were compared to results using brass mounting studs. Validation or rejection of the concept was determined from statistical analysis on the mean and variance of collected SPT test data.

The concept of using 3D printed thermoplastic for mounting stud fabrication is a promising option; however, the concept should be verified with more extensive research using a variety of asphalt mixes and operators to ensure no bias in the repeatability and reproducibility of test results. The Polycarbonate (PC) had a stronger layer bonding than ABS and PLA while printing. It was recommended for follow up studies.

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Date Created
  • 2018