Matching Items (17)

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Mechanical Design for TolTEC Optics

Description

The following paper discusses the validation of the TolTEC optical design along with a progress report regarding the design of the optical mounting system. Solidworks and Zemax were used in

The following paper discusses the validation of the TolTEC optical design along with a progress report regarding the design of the optical mounting system. Solidworks and Zemax were used in conjunction to model the proposed optics designs. The final optical design was selected through extensive CAD modeling and testing within the Large Millimeter Telescope receiver room. The TolTEC optics can be divided into two arrays, one comprised of the warm mirrors and the second, cryogenically-operated cold mirrors. To ensure structural stability and optical performance, the mechanical design of these systems places a heavy emphasis on rigidity. This is done using a variety of design techniques that restrict motion along the necessary degrees of freedom and maximize moment of inertia while minimizing weight. Work will resume on this project in the Fall 2017 semester.

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Created

Date Created
  • 2017-05

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Optics Plate Assembly for Balloon-borne Large Aperture Submillimeter Telescope (BLAST)

Description

Balloon-borne telescopes are an economic alternative to scientists seeking to study light compared to other ground- and space-based alternatives, such as the Keck Observatory and the Hubble Space Telescope. One

Balloon-borne telescopes are an economic alternative to scientists seeking to study light compared to other ground- and space-based alternatives, such as the Keck Observatory and the Hubble Space Telescope. One such balloon-borne telescope is the Balloon-borne Large Aperture Submillimeter Telescope, or simply BLAST. Arizona State University was tasked with assembling one of the primary optics plates for the telescope's next mission. This plate, detailed in the following paragraphs, is designed to detect and capture submillimeter wavelength light. This will help scientists understand the formation and early life of stars. Due to its highly sensitive nature detecting light, the optics plate had to be carefully assembled following a strict assembly and testing procedure. Initially, error tolerances for the mirrors and plate were developed using a computer model, later to be compared to measured values. The engineering decisions made throughout the process pertained to every aspect of the plate, from ensuring the compliance of the engineering drawings to the polishing of the mirrors for testing. The assembly procedure itself was verified at the conclusion using a coordinate measuring machine (CMM) to analyze whether or not the plate was within defined error tolerances mentioned above. This data was further visualized within the document to show that the assembly procedure of the BLAST optics plate was successful. The largest error margins seen were approximately one order of magnitude lower than their tolerated limits, reflecting good engineering judgement and care applied to the manufacturing process. The plate has since been shipped offsite to continue testing and the assembly team is confident it will perform well within expected parameters.

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Created

Date Created
  • 2016-05

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Investigation and Testing of the Performance and Durability of Ultra Small Diameter Micro-machining Tools.

Description

The world of micro-tools and micro-machining is still being explored, and new manufacturing processes and tools are being developed by researchers and industry leaders alike. Many of the performance metrics

The world of micro-tools and micro-machining is still being explored, and new manufacturing processes and tools are being developed by researchers and industry leaders alike. Many of the performance metrics for ultra-small machining tools (like end mills) are still underdefined or are currently being determined. The objective of this investigation was to determine the performance and durability of the 15 micron (um) diameter micro tool manufactured by the company Performance Micro Tool (PMT). The performance of the tool was measured by the surface roughness that resulted from the micro end mill's tool path. The durability of the tool was measured by the overall linear distance cut by the end mill before complete tool failure. In total, two micro-tools were tested, and the performance and durability results were surprising and significant. The tools surpassed the initial expectations of immediate failure upon contact with the base model. The expectation of failure stemmed from the less than ideal testing conditions for the tools -- a milling machine not capable of ideal cutting parameters and imperfections in the base model manufacturing. In terms of durability, both tools survived the entire defined tool path; over 5,000 times the tool diameter, a comparable metric for industry macro tools. The performance of the end mills was spectacular, both toolpaths had average surface roughness values below 0.05um, which is lower than the industry standard for some of the highest cut quality. Ultimately, the consistent results from both tools encourages a deeper investigation into these micro-tools. The fact that both tools exceeded expectations means that an investigation of many more tools is worth the financial and time investment. A further investigation of a large number of micro-tools could yield a standardized metric for performance and durability for the 15um tools.

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Created

Date Created
  • 2016-05

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An Automated Test System for Terahertz Receiver Characterization

Description

An automated test system was developed to characterize detectors for the Kilopixel Array Pathfinder Project (KAPPa). KAPPa is an astronomy instrument that detects light at terahertz wavelengths using a 16-pixel

An automated test system was developed to characterize detectors for the Kilopixel Array Pathfinder Project (KAPPa). KAPPa is an astronomy instrument that detects light at terahertz wavelengths using a 16-pixel heterodyne focal plane array. Although primarily designed for the KAPPa receiver, the test system can be used with other instruments to automate tests that might be tedious and time-consuming by hand. Mechanical components of the test setup include an adjustable structure of aluminum t-slot framing that supports a rotating chopper. Driven by a stepper motor, the chopper alternates between blackbodies at room temperature and 77 K. The cold load consists of absorbing material submerged in liquid nitrogen in an open Styrofoam cooler. Scripts written in Matlab and Python control the mechanical system, interface with receiver components, and process data. To calculate the equivalent noise temperature of a receiver, the y-factor method is used. Test system operation was verified by sweeping the local oscillator frequency and power level for two room temperature Schottky diode receivers from Virginia Diodes, Inc. The test system was then integrated with the KAPPa receiver, providing a low cost, simple, adaptable means to measure noise with minimal user intervention.

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Created

Date Created
  • 2014-05

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Searching for Stellar Outflow in the R Coronae Australis Region

Description

Using data from the Arizona Radio Observatory Submillimeter Telescope, we have studied the active, star-forming region of the R Coronae Australis molecular cloud in 12CO (2-1), 13CO (2-1), and HCO+

Using data from the Arizona Radio Observatory Submillimeter Telescope, we have studied the active, star-forming region of the R Coronae Australis molecular cloud in 12CO (2-1), 13CO (2-1), and HCO+ (3-2). We baselined and mapped the data using CLASS. It was then used to create integrated intensity, outflow, and centroid velocity maps in IDL. These clearly showed the main large outflow, and then we identified a few other possible outflows.

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Created

Date Created
  • 2014-05

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Frequency–Modulated Continuous–Wave Millimeter–Band Radar for Volcanic Ash Detection

Description

The use of conventional weather radar in vulcanology leads to two problems: the radars often use wavelengths which are too long to detect the fine ash particles, and they cannot

The use of conventional weather radar in vulcanology leads to two problems: the radars often use wavelengths which are too long to detect the fine ash particles, and they cannot be field–adjusted to fit the wide variety of eruptions. Thus, to better study these geologic processes, a new radar must be developed that is easily reconfigurable to allow for flexibility and can operate at sufficiently short wavelengths.

This thesis investigates how to design a radar using a field–programmable gate array board to generate the radar signal, and process the returned signal to determine the distance and concentration of objects (in this case, ash). The purpose of using such a board lies in its reconfigurability—a design can (relatively easily) be adjusted, recompiled, and reuploaded to the hardware with none of the cost or time overhead required of a standard weather radar.

The design operates on the principle of frequency–modulated continuous–waves, in which the output signal frequency changes as a function of time. The difference in transmit and echo frequencies determines the distance of an object, while the magnitude of a particular difference frequency corresponds to concentration. Thus, by viewing a spectrum of frequency differences, one is able to see both the concentration and distances of ash from the radar.

The transmit signal data was created in MATLAB®, while the radar was designed with MATLAB® Simulink® using hardware IP blocks and implemented on the ROACH2 signal processing hardware, which utilizes a Xilinx® Virtex®–6 chip. The output is read from a computer linked to the hardware through Ethernet, using a Python™ script. Testing revealed minor flaws due to the usage of lower–grade components in the prototype. However, the functionality of the proposed radar design was proven, making this approach to radar a promising path for modern vulcanology.

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Agent

Created

Date Created
  • 2019-05

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Frequency–Modulated Continuous–Wave Millimeter–Band Radar for Volcanic Ash Detection

Description

The use of conventional weather radar in vulcanology leads to two problems: the radars often use wavelengths which are too long to detect the fine ash particles, and they cannot

The use of conventional weather radar in vulcanology leads to two problems: the radars often use wavelengths which are too long to detect the fine ash particles, and they cannot be field–adjusted to fit the wide variety of eruptions. Thus, to better study these geologic processes, a new radar must be developed that is easily reconfigurable to allow for flexibility and can operate at sufficiently short wavelengths.

This thesis investigates how to design a radar using a field–programmable gate array board to generate the radar signal, and process the returned signal to determine the distance and concentration of objects (in this case, ash). The purpose of using such a board lies in its reconfigurability—a design can (relatively easily) be adjusted, recompiled, and reuploaded to the hardware with none of the cost or time overhead required of a standard weather radar.

The design operates on the principle of frequency–modulated continuous–waves, in which the output signal frequency changes as a function of time. The difference in transmit and echo frequencies determines the distance of an object, while the magnitude of a particular difference frequency corresponds to concentration. Thus, by viewing a spectrum of frequency differences, one is able to see both the concentration and distances of ash from the radar.

The transmit signal data was created in MATLAB®, while the radar was designed with MATLAB® Simulink® using hardware IP blocks and implemented on the ROACH2 signal processing hardware, which utilizes a Xilinx® Virtex®–6 chip. The output is read from a computer linked to the hardware through Ethernet, using a Python™ script. Testing revealed minor flaws due to the usage of lower–grade components in the prototype. However, the functionality of the proposed radar design was proven, making this approach to radar a promising path for modern vulcanology.

Contributors

Agent

Created

Date Created
  • 2019-05

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Thermal and Electrical Characterization of the High Gain Warm IF Amplifier for the GUSTO Radio Astronomy Instrument

Description

The work presented herein will present the methodology and results for characterizing the thermal and electrical characteristics of the high gain warm IF amplifiers being developed by Arizona State University

The work presented herein will present the methodology and results for characterizing the thermal and electrical characteristics of the high gain warm IF amplifiers being developed by Arizona State University (ASU) for the GUSTO radio astronomy instrument. Thermal analysis will be performed in the form of Thermal Desktop simulations, hand calculations, and lab measurements. The electrical characteristics of the LNA design are then examined by collecting S-parameter measurements of the entire GUSTO band across a temperature range of -40°C to +70°C. Ultimately, the work performed justifies that ASU’s design of the GUSTO electronics is capable of meeting all technical requirements necessary to achieve mission success.

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Created

Date Created
  • 2019-05

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Possible counterparts of IceCube high energy neutrinos

Description

The IceCube Neutrino Observatory has provided the first map of the high energy (~0.01 – 1 PeV) sky in neutrinos. Since neutrinos propagate undeflected, their arrival direction is an important

The IceCube Neutrino Observatory has provided the first map of the high energy (~0.01 – 1 PeV) sky in neutrinos. Since neutrinos propagate undeflected, their arrival direction is an important identifier for sources of high energy particle acceleration. Reconstructed arrival directions are consistent with an extragalactic origin, with possibly a galactic component, of the neutrino flux. We present a statistical analysis of positional coincidences of the IceCube neutrinos with known astrophysical objects from several catalogs. For the brightest gamma-ray emitting blazars and for Seyfert galaxies, the numbers of coincidences is consistent with the random, or “null”, distribution. Instead, when considering starburst galaxies with the highest flux in gamma-rays and infrared radiation, up to n = 8 coincidences are found, representing an excess over the ~4 predicted for the null distribution. The probability that this excess is realized in the null case, the p-value, is p = 0.042. This value falls to p = 0.003 for a set of gamma-ray detected starburst galaxies and superbubbles in the galactic neighborhood. Therefore, it is possible that these might account for a subset of IceCube neutrinos. The physical plausibility of such correlation is discussed briefly.

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Created

Date Created
  • 2015

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Single photon interferometry and quantum astrophysics

Description

This thesis contains an overview, as well as the history of optical interferometers. A new approach to interferometric measurements of stars is proposed and explored. Modern updates to the classic

This thesis contains an overview, as well as the history of optical interferometers. A new approach to interferometric measurements of stars is proposed and explored. Modern updates to the classic techniques are described along with some theoretical derivations showing why the method of single photon counting shows significant promise relative to the currently used amplitude interferometry.

Description of a modular intensity interferometer system using commercially available single-photon detectors is given. Calculations on the sensitivity and \emph{uv}-plane coverage using these modules mounted on existing telescopes on Kitt Peak, Arizona is presented.

Determining fundamental stellar properties is essential for testing models of stellar evolution as well as for deriving physical properties of transiting exoplanets. The proposed method shows great promise in measuring the angular size of stars. Simulations indicate that it is possible to measure stellar diameters of bright stars with AB magnitude <6 with a precision of >5% in a single night of observation.

Additionally, a description is given of a custom time-to-digital converter designed to time tag individual photons from multiple single-photon detectors with high count rate, continuous data logging, and low systematics. The instrument utilizes a tapped-delay line approach on an FPGA chip which allows for sub-clock resolution of <100 ps. The TDC is implemented on a Re-configurable Open Architecture Computing Hardware Revision 2 (ROACH2) board which allows for continuous data streaming and time tagging of up to 20 million events per second. The functioning prototype is currently set-up to work with up to ten independent channels. Laboratory characterization of the system, including RF, pick up and mitigation, as well as measurement of in-lab photon correlations from an incoherent light source (artificial star), are presented. Additional improvements to the TDC will also be discussed, such as improving the data transfer rate by a factor of 10 via an SDP+ Mezzanine card and PCIe 2SFP+ 10 Gb card, as well as scaling to 64 independent channels.

Furthermore, a modified nulling interferometer with image inversion is proposed, for direct imaging of exoplanets below the canonical Rayleigh resolution limit. Image inversion interferometry relies on splitting incoming radiation from a source, either spatially rotating or reflecting the electric field from one arm of the interferometer before recombining the signals and detecting the resulting images in the two output ports with an array of high-speed single-photon detectors. Sources of incoming radiation that have cylindrical symmetry and are centered on the rotation axis will cancel in one of the output ports and add in the other output port. The ability to suppress light from a host star, as well as the ability to resolve past the Rayleigh limit, enables sensitive detection of exoplanets from a stable environment without the need for a coronagraph. The expected number of photons and the corresponding variance in the measurement for different initial contrast ratios are shown, with some first-order theoretical instrumental errors.

Lastly, preliminary results from a sizeable photometric survey are presented. This survey is used to derive bolometric flux alongside from angular size measurements and the effective stellar temperatures.

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Created

Date Created
  • 2018