227 research outputs found
Results from POLARBEAR and plans for the Simons Array
No full textHalverson, Nils. (2015). Results from POLARBEAR and plans for the Simons Array. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/169736
Halverson
No full textVideorecording of a modern dance graduate thesis concert presented March 12 and 13, 1981 on the University of Utah campus. The program consisted of four dance pieces, and the first, Spellfeud, was choreographed by the author. The other dances were title Distances, Monologue for a tortoise and Entwined weavings
Hybrid metamaterial lenslet arrays for millimeter and submillimeter imaging
No full textWe are developing broadband metamaterial planar lenslet arrays for millimeter and submillimeter imaging using stacked silicon wafers patterned with subwavelength copper squares, deep reactive ion etched (DRIE) holes, or a hybrid combination of the two. Beam-forming is accomplished through spatial variation in refractive index within each pixel created by these subwavelength features, a gradient-index (GRIN) design. However, the optical properties of both the metal mesh and DRIE metamaterials exhibit dependence on polarization orientation and wavelength, posing challenges for lens design. We combine metal mesh and DRIE GRIN sections to leverage the contrasting polarization- and frequency-dependent properties of the two material types. Here we present measurements of our most recent prototype metamaterial GRIN lens on sinuous antenna-coupled TES detectors from 88 to 225 GHz. We also present design studies extending to higher frequencies and optimizing for different pixel pitches
'Escape...The Orange Way' Rajneesh Newsletter
No full textAn article by Dean C. Halverson titled, 'Escape...The Orange Way,' from the SCP Newsletter of February-March 1982. This newsletter was issued by the 'Spiritual Counterfeits Project,' a Christian group connected to Campus Crusade for Christ that was dedicated to exposing religious frauds. The author provides a skeptical take on the teachings, standards and beliefs within the Rajneeshpuram commune. It describes the purpose of the self-sufficient city and how one can become a disciple to Bhagwan Shree Rajneesh. The text further explains the Rajneesh Foundation's intention to expand the city of Rajneeshpuram. The article was intended to warn others about the dangers of Rajneesh beliefs. This item was a part of the papers of Bob Oliver, Governor Atiyeh's legal counsel
Yern and Inger Grimland Family
No full textLarge family group, posing on front lawn and porch, honoring the Golden Wedding Anniversary of Inger and Yern Grimland. Those indentified are Tellef Grimland, Marren Grimland, Clara Swenson Grimland, J K Grimland, Annie Olson Grimland, Ole Solberg, Kerste Grimland Solberg, Nils Grimalnd, Mary Johnson Grimland, Gunsten Grimland, Sphie Brown Grimland, Yern Grimalnd, Inger Halverson Grimland, Mrs Thornson, Rev Thornson, Inger's sisters (in white) back of Yern, far right Hilma and Oscar J Re
Cosmological Constraints from a Measurement of the Polarization Power Spectra of the Cosmic Microwave Background with the SPTpol Experiment
No full textSPTpol is a polarization-sensitive receiver installed on the South Pole Telescope in its third season of mapping Cosmic Microwave Background (CMB) temperature and polarization anisotropies. The receiver contains 588 (180) dual polarization pixels at 150 (95) GHz comprising a total of 1536 transition edge sensor bolometers. In its first year, SPTpol mapped 100 deg2 to a depth of ~ 8 and 10 µK-arcmin at 150 GHz in temperature and polarization, respectively. With this deep field map, the SPTpol collaboration produced the first statistically significant detection (7.7 σ) of gravitational lensing B-mode polarization. Additionally, the SPTpol experiment just completed its first of three years mapping 500 deg2 to a depth of ~ 12 and 15 µK-arcmin in temperature and polarization at 150 GHz. High signal-to-noise measurements of the polarization power spectra from the survey will further constrain cosmological parameters and extensions to the λCDM cosmological model. Measurements of large-scale polarization anisotropies will also place tighter constraints on the existence of primordial B-mode polarization generated by gravitational waves from the epoch of inflation.
In this work we discuss the development of the SPTpol receiver and, in particular, the seven 150 GHz detector modules at the heart of the focal plane. We describe the observational strategies used during the first two seasons of SPTpol measurements as well as the reduction of detector timestreams into maps and CMB polarization power spectra. To extract constraints on cosmological parameters from the SPTpol power spectra we have written a new Bayesian likelihood module for the CosmoMC Markov Chain Monte Carlo package, which we also describe. Finally, we present cosmological constraints from the first year of SPTpol observations. Pre-existing constraints on λCDM parameters improve by a few percent with the inclusion of these data. While this is a modest step forward in our understanding of the early universe, the completed SPTpol dataset will have the power to tightly constrain the sum of neutrino masses and help determine the source of recently detected large-scale B-mode polarization.</p
Microwave Kinetic Inductance Detector Camera Development for Millimeter-Wave Astrophysics
No full textThis thesis describes my contribution to the design, assembly and testing required for a camera using antenna-coupled Microwave Kinetic Inductance Detectors (MKIDs). MKIDs are super-conducting resonators in which the resonance frequency and quality factor are sensitive measures of Cooper pairs broken by incident radiation. The MKID camera, called the Multicolor Submillimeter Inductance Camera (MUSIC), is built to detect and characterize the physics of dusty submillimeter galaxies, the primary component of the far-infrared background discovered by the COBE satellite. The camera will have 576 pixels sensitive to 4 colors simultaneously in the range of 150-360 GHz. With these bands, combined with shorter wavelength data from instruments on the Spitzer and Herschel far-infrared satellites, we can find the integrated flux from high-redshift dusty galaxies and identify galaxies likely to be at extremely high redshift. We have achieved first light using a demonstration instrument ("DemoCam"), testing two colors, centered at 240 GHz and 350 GHz, in 2007, and demonstrated three-color operation in 2010.
In the thesis is discussed the design, testing and optimization of DemoCam, in particular its function in testing several iterations of arrays of antenna-coupled MKID resonators. The arrays tested are 4×4 arrays of two-color antenna pixels, and newer 6×6 arrays of three-color antenna pixels, the latter with a "dark" or uncoupled resonator for each antenna. This testing has been used to explore the physics of the detectors, test which properties maximize the detector signal-to-noise ratio, and to inform the MKID camera's optical design. The goal of this testing is find how to improve sensitivity to minimize Noise Equivalent Power in the presence of large background loads, as in ground-based sub/millimeter astronomy. The DemoCam is shown to reach interesting levels of sensitivity on the sky in three colors (230, 290 and 350 GHz), and to have effective calibration mechanisms, with the readout system used for the final camera
Microwave Kinetic Inductance Detector Camera Development for Millimeter-Wave Astrophysics
No full textThis thesis describes my contribution to the design, assembly and testing required for a camera using antenna-coupled Microwave Kinetic Inductance Detectors (MKIDs). MKIDs are super-conducting resonators in which the resonance frequency and quality factor are sensitive measures of Cooper pairs broken by incident radiation. The MKID camera, called the Multicolor Submillimeter Inductance Camera (MUSIC), is built to detect and characterize the physics of dusty submillimeter galaxies, the primary component of the far-infrared background discovered by the COBE satellite. The camera will have 576 pixels sensitive to 4 colors simultaneously in the range of 150-360 GHz. With these bands, combined with shorter wavelength data from instruments on the Spitzer and Herschel far-infrared satellites, we can find the integrated flux from high-redshift dusty galaxies and identify galaxies likely to be at extremely high redshift. We have achieved first light using a demonstration instrument ("DemoCam"), testing two colors, centered at 240 GHz and 350 GHz, in 2007, and demonstrated three-color operation in 2010.
In the thesis is discussed the design, testing and optimization of DemoCam, in particular its function in testing several iterations of arrays of antenna-coupled MKID resonators. The arrays tested are 4×4 arrays of two-color antenna pixels, and newer 6×6 arrays of three-color antenna pixels, the latter with a "dark" or uncoupled resonator for each antenna. This testing has been used to explore the physics of the detectors, test which properties maximize the detector signal-to-noise ratio, and to inform the MKID camera's optical design. The goal of this testing is find how to improve sensitivity to minimize Noise Equivalent Power in the presence of large background loads, as in ground-based sub/millimeter astronomy. The DemoCam is shown to reach interesting levels of sensitivity on the sky in three colors (230, 290 and 350 GHz), and to have effective calibration mechanisms, with the readout system used for the final camera
Cosmological Constraints from a Measurement of the Polarization Power Spectra of the Cosmic Microwave Background with the SPTpol Experiment
No full textSPTpol is a polarization-sensitive receiver installed on the South Pole Telescope in its third season of mapping Cosmic Microwave Background (CMB) temperature and polarization anisotropies. The receiver contains 588 (180) dual polarization pixels at 150 (95) GHz comprising a total of 1536 transition edge sensor bolometers. In its first year, SPTpol mapped 100 deg2 to a depth of ~ 8 and 10 µK-arcmin at 150 GHz in temperature and polarization, respectively. With this deep field map, the SPTpol collaboration produced the first statistically significant detection (7.7 σ) of gravitational lensing B-mode polarization. Additionally, the SPTpol experiment just completed its first of three years mapping 500 deg2 to a depth of ~ 12 and 15 µK-arcmin in temperature and polarization at 150 GHz. High signal-to-noise measurements of the polarization power spectra from the survey will further constrain cosmological parameters and extensions to the λCDM cosmological model. Measurements of large-scale polarization anisotropies will also place tighter constraints on the existence of primordial B-mode polarization generated by gravitational waves from the epoch of inflation.
In this work we discuss the development of the SPTpol receiver and, in particular, the seven 150 GHz detector modules at the heart of the focal plane. We describe the observational strategies used during the first two seasons of SPTpol measurements as well as the reduction of detector timestreams into maps and CMB polarization power spectra. To extract constraints on cosmological parameters from the SPTpol power spectra we have written a new Bayesian likelihood module for the CosmoMC Markov Chain Monte Carlo package, which we also describe. Finally, we present cosmological constraints from the first year of SPTpol observations. Pre-existing constraints on λCDM parameters improve by a few percent with the inclusion of these data. While this is a modest step forward in our understanding of the early universe, the completed SPTpol dataset will have the power to tightly constrain the sum of neutrino masses and help determine the source of recently detected large-scale B-mode polarization.</p
Increasing the Detail and Sensitivity of Far-Infrared/Submillimeter Observations In Astrophysics: Kinetic Inductance Detector Development and Molecular Gas Dynamics In Galaxy Merger NGC 6240
No full textTo push the boundaries of astrophysics we need to be able to look at the universe in increasing detail. This thesis work advances this goal in two ways: with a technology development project and by using existing technology to investigate an archetypal merging galaxy in extreme detail.
Technology development: Far-infrared observations are ultimately limited by the background radiation emitted by our galaxy and solar system. Large far-infrared observatories that are limited by this background will be critical for understanding galactic and star formation histories over time. To enable this goal, arrays of far-infrared detectors with high enough sensitivities to be astrophysical background limited need to be developed. Working with a team from the Jet Propulsion Laboratory and the National Institute for Standards and Technology, I have investigated two methods for increasing the sensitivities of kinetic inductance detectors (KIDs) in the far-infrared. First, we have fabricated low-volume aluminum and aluminum/titanium nitride bilayer devices to decrease active detector metal volume thereby increasing responsivity. To optimize future iterations on these designs, I have also measured signal lifetimes as a function of aluminum thickness. Second, we investigated phonon recycling devices (simulations and fabrications) that trap phonons generated by recombining Cooper pairs in the active area to elongate quasi-particle recombination time, thereby boosting responsivity.
Observational component: Galactic mergers are immensely complex, often resulting in tidal tails, extremely turbulent gas, active galactic nuclei (AGN), superwinds, and bursts in star formation to only name a few impacts. Using the Atacama Large Millimeter Array (ALMA), I observe the molecular gas in the well-studied galaxy merger NGC 6240 in more detail than ever before.We analyze high-resolution observations of CO J = 3 − 2 and 6 − 5 of the central few kpc of NGC 6240 taken with ALMA. Using these CO line observations, we model the kinematics of the molecular gas located between the nuclei of the progenitor galaxies. Our models suggest this gas is a tidal bridge linking the two nuclei that could fall onto the nuclei prior to second pass and feed future starbursts. We also observe high velocity gas (> 300 km/s) that could be accelerated by either gravitational forces from the merger or an AGN outflow. These findings shed light onto small-scale processes that can affect galaxy evolution and the corresponding star formation, with the tidal bridge depositing molecular gas onto the nuclei while other energetic forces accelerate molecular gas further out of the nuclear region.</p
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