Download or read book Detectors for the Atacama Cosmology Telescope written by Tobias Andrew Marriage and published by . This book was released on 2006 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Atacama Cosmology Telescope (ACT) will make measurements of the brightness temperature anisotropy in the Cosmic Microwave Background (CMB) on degree to arcminute angular scales. The ACT observing site is located 5200 m near the top of Cerro Toco in the Atacama Desert of northern Chile. This thesis presents research on the detectors which capture the image of the CMB formed at ACT's focal plane. In the first chapter, the primary brightness temperature fluctuations in the Cosmic Microwave Background are reviewed. In Chapter 2, a calculation shows how the CMB brightness is translated by ACT to an input power to the detectors. Chapter 3 describes the ACT detectors in detail and presents the response and sensitivity of the detectors to the input power computed in Chapter 2. Chapter 4 describes the detector fabrication at NASA Goddard Space Flight Center. Chapter 5 summarizes experiments which characterize the ACT detector performance.
Download or read book Detector Development and Polarization Analyses for the Atacama Cosmology Telescope written by Brian James Koopman and published by . This book was released on 2018 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: We are currently in an era of precision cosmology. Study of the Cosmic Microwave Background (CMB) has been central to our understanding of the universe ever since its discovery in 1965. Recent results from the Planck satellite have provided the best constraints on the 6-parameter $\Lambda\mathrm{CDM}$ model, the "standard model'' of cosmology. In order to improve these constraints we must further the development of the technologies used to measure the CMB as well as our understanding of their associated systematics. The Atacama Cosmology Telescope Polarimeter (ACTPol) and its successor instrument, known as Advanced ACTPol (AdvACT), are polarization sensitive upgrades to the Atacama Cosmology Telescope (ACT). ACT is an off-axis Gregorian telescope with a 6m primary reflector and a 2m secondary reflector. The ACTPol and AdvACT instruments utilize kilo-pixel scale arrays of superconducting transition edge sensor (TES) bolometers to measure the CMB anisotropies at frequencies ranging from 27-220 GHz. The increased spectral coverage of AdvACT will enable a wide range of CMB science, such as improving constraints on dark energy, the sum of the neutrino masses, and the existence of primordial gravitational waves. Precise polarization calibration can also enable improved constraints on cosmic polarization rotation. In this thesis we present an overview of the AdvACT instrument before detailing the development of the AdvACT TES device geometries, which are tuned specifically for each of AdvACT's five frequency bands (27, 39, 90, 150, and 220 GHz). Each detector couples to a single linear polarization. The angle of this coupling projected onto the sky is a critical calibration step in making maps of the CMB polarization. Any offset in this calibration angle can introduce a spurious B-mode polarization signal, resulting in non-zero EB and TB cross-correlation power spectra. ACTPol uses a unique optical modeling based approach to this calibration. We present this procedure, as well as a method for directly measuring the relative angles of the detectors by use of a rapidly rotating polarizer. We also present maps of the polarized source Tau A, from the first three seasons of ACTPol at 90 and 150 GHz and discuss how these maps are affected by the polarization calibration. Finally, we discuss the telescope control, computer systems, and remote observations team which keep the telescope running, and briefly conclude with a summary that motivates improving calibration techniques for future CMB experiments.
Download or read book Exploring the Universe with the Atacama Cosmology Telescope written by Marius Lungu and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past twenty-five years, observations of the Cosmic Microwave Background (CMB) temperature fluctuations have served as an important tool for answering some of the most fundamental questions of modern cosmology: how did the universe begin, what is it made of, and how did it evolve? More recently, measurements of the faint polarization signatures of the CMB have offered a complementary means of probing these questions, helping to shed light on the mysteries of cosmic inflation, relic neutrinos, and the nature of dark energy. A second-generation receiver for the Atacama Cosmology Telescope (ACT), the Atacama Cosmology Telescope Polarimeter (ACTPol), was designed and built to take advantage of both these cosmic signals by measuring the CMB to high precision in both temperature and polarization. The receiver features three independent sets of cryogenically cooled optics coupled to transition-edge sensor (TES) based polarimeter arrays via monolithic silicon feedhorn stacks. The three detector arrays, two operating at 149 GHz and one operating at both 97 and 149 GHz, contain over 1000 detectors each and are continuously cooled to a temperature near 100 mK by a custom-designed dilution refrigerator insert. Using ACT's six meter diameter primary mirror and diffraction limited optics, ACTPol is able to make high-fidelity measurements of the CMB at small angular scales (l ~ 9000), providing an excellent complement to Planck. The design and operation of the instrument are discussed in detail, and results from the first two years of observations are presented. The data are broadly consistent with /\CDM and help improve constraints on model extensions when combined with temperature measurements from Planck.
Download or read book Development of Technologies for the Atacama Cosmology Telescope and Next Generation Cosmic Microwave Background Instruments written by Jonathan Ward and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A primary goal of modern cosmology is to obtain cosmological information and parameters from high-sensitivity measurements of the temperature and polarization of the Cosmic Microwave Background (CMB) radiation. These measurements will allow cosmologists to probe the many predictions made by the inflationary model of the Universe. To continue expanding the limits of CMB science, experimentalists need to develop novel technologies that will continue to improve our ability to observe the microwave sky. Paired with state of the art data analysis techniques, our understanding of the Universe will continue to grow now and for decades to come.The Atacama Cosmology Telescope (ACT) is a 6-meter diameter telescope located in the Andes Mountains of Northern Chile. Deployment of the Advanced ACTPol (AdvACT) receiver has vastly improved the capabilities of ACT. Next-generation detector arrays operating at 20, 40, 90, 150, and 240 GHz will provide the frequency coverage and detector count necessary to improve measurements of a wide range of cosmological parameters. Continuously rotating half-wave plates (HWPs) modulate the incoming polarized signal, resulting in a drastic suppression of the atmospheric 1/f noise that contaminates the ACT data at large angular scales. Finally, hardware and software upgrades to previous-generation ACTPol infrastructure have further improved the AdvACT instrument on the fronts of cryogenic performance, housekeeping data acquisition, assembly procedure, and site reliability. The design and deployment of AdvACT instrumentation is discussed in detail from Chapters 2-4, highlighting the key design changes and improvements over the ACTPol experiment. In addition to the instrumentation advances discussed above, data analysis and numerical modeling techniques provide the framework needed to extract the most information from the data gathered by the AdvACT experiment. Key efforts focused towards processing HWP data allows ACT to probe the inflationary gravitational wave signal that may lie in the low-frequency regime of the ACT data. Furthermore, simulations help predict the effects of various systematics on the raw data give a better understanding of what calibration strategies are needed to mitigate systematic effects. The software developed to accomplish these tasks is discussed in Chapters 5-6, along with the results obtained from the data when the code is implemented in the analysis pipeline. The technologies, instrumentation, and analysis techniques outlined in this paper and employed by the AdvACT experiment will continue to push ACT to the forefront of experimental cosmology research while also providing a template for future experimental efforts.
Download or read book Probing the Cosmic Microwave Background Radiation Using Large Superconducting Detector Arrays written by Yaqiong Li and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The discovery and measurements of the Cosmic Microwave Background (CMB) radiation have laid the foundation of the current cosmological model, in which the universe is primarily composed of dark energy and dark matter. Higher-precision measurements of the CMB temperature and polarization anisotropies, enabled by installation of larger numbers of superconducting detectors, will unveil more information about the universe.This thesis will present my work in the Advanced Atacama Cosmology Telescope Polarimeter (AdvACT) and the Simons Observatory (SO). Both the AdvACT and SO are located at ~5200m altitude on Cerro Toco in the Atacama Desert in Chile. The AdvACT is the second and final instrument upgrade of the Atacama Cosmology Telescope (ACT), and is one of the most sensitive ground-based instruments for measuring the CMB anisotropies at small angular scales. The total number of detectors that the SO plans to deploy is one magnitude higher than the AdvACT. The major content of this thesis is related to the development, design, integration and test of the multichroic detector arrays of these two instruments.
Download or read book Astrophysical Techniques written by C.R. Kitchin and published by CRC Press. This book was released on 2020-07-27 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: Long used in undergraduate and introductory graduate courses, Astrophysical Techniques, Seventh Edition provides an accessible yet comprehensive account of the innovate instruments, detectors, and techniques employed in astronomy and astrophysics. Emphasizing the underlying unity of all astronomical observations, this popular textbook provides a coherent state-of-the-art account of the instruments and techniques used in current astronomy and astrophysics. Fully updated throughout, this seventh edition builds upon the sixth edition, covering improved techniques and cutting-edge methods in the field, as well as other exciting new developments in gravitational waves, dark matter and energy, the use of photonics, and astronomy education and outreach, in addition to further detailed discussions on the latest scientific instruments and individual detectors. The book is written in a very accessible manner, and most of the mathematics is accessible to those who have attended a mathematics course in their final years at school. Nevertheless, the treatment of the topics in general is at a sufficiently high level to be of use to those professionals seeking technical information in areas of astronomy with which they might not be completely familiar. Key Features: Details the instrumentation and theory of astronomical observations, including radio waves, gamma rays, cosmic rays, neutrinos, gravitational waves and dark matter and energy and more Presents the background theory and operating practice of state-of-the-art detectors and instruments Fully updated to contain the latest technology and research developments
Download or read book Optimizing Future CMB Observatories and Measuring Galaxy Cluster Motions with the Atacama Cosmology Telescope written by Patricio Andres Gallardo Matamala and published by . This book was released on 2019 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cosmic Microwave Background (CMB) experiments are a great tool to probe the universe's history and content. In the recent decade, great progress in large format detector array technologies has allowed increased sensitivity and sky coverage, which has enabled very precise measurements. The next generation of CMB experiments will offer larger focal planes, which will allow measurements with exquisite precision. In this thesis, the following studies are presented: The development of a silicon meta-material deep reactive ion etched anti-reflection coating for use in sub-millimeter wavelengths. Characterization of the aliased detector noise performance of the Atacama Cosmology Telescope (ACT), a current polarization sensitive six-meter telescope that observes the CMB at arcminute resolution. Optical models developed to describe the pickup and sidelobes characteristics of the ACT. These models are currently being used to optimize the design of the Simons Observatory, a next generation six-meter telescope with increased sensitivity. Studies of the motions of clusters of galaxies via the pairwise kinetic Sunyaev-Zeldovich effect (the frequency-distortion of the cold CMB light due to the interaction with the hot inter-cluster ionized gas), with data from ACT.
Download or read book Characterization of Transition Edge Sensors for the Millimeter Bolometer Array Camera on the Atacama Cosmology Telescope written by Yue Zhao and published by . This book was released on 2010 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cryogenic Optics and Detectors for Next generation Microwave Cosmology and Astrophysics Observatories written by Nicholas Flood Cothard and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Millimeter and sub-millimeter observatories provide a unique and powerful window into the origins, content, and evolution of the universe. In our current era of precision cosmology, measurements of the cosmic microwave background (CMB) yield constraints on frontier physics such as dark energy, the sum of the neutrino masses, and models of inflation. Measurements of the CMB also reveal the astrophysics of galaxy clusters and can then be used to glean information about the early universe. The early universe can also be studied with millimeter-wave observations of redshifted spectral line emissions from early star-forming galaxies during the Epoch of Reionization (EoR). A relatively new method, called spectral line intensity mapping (LIM), can be used to tomographically map the EoR. LIM observations of the EoR will reveal properties of the reionization sources and how reionization impacted the evolution of the intergalactic medium (IGM) into the large-scale structure we see today. In order to improve CMB observations and enable new LIM measurements, microwave observatories require high-throughput cryogenic optics and interferometry, and ultra-sensitive superconducting detectors. This dissertation presents developments of these technologies for three projects : the Atacama Cosmology Telescope (ACT), the CCAT-prime Observatory, and the Simons Observatory (SO). We begin with a presentation of in-situ warm spillover beam measurements of the Advanced ACT receiver, which have been used to improve the optical designs of future telescopes. We then discuss the design, models, and fabrication development of metamaterial-based, silicon-substrate, Fabry-Perot interferometers for CCAT-prime's [CII] LIM instrument. We then describe the characterization of prototype superconducting transition edge sensors (TES) for Simons Observatory including, critical temperature, saturation power, time constant, and complex impedance measurements. The dissertation concludes with a brief discussion of the cosmology and astrophysics science goals that these technologies will enable when they are deployed on microwave telescopes in the coming years.
Download or read book Observational Astronomy written by Edmund C. Sutton and published by Cambridge University Press. This book was released on 2011-10-13 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astronomy is fundamentally an observational science and as such it is important for astronomers and astrophysicists to understand how their data are collected and analyzed. This book is a comprehensive review of current observational techniques and instruments. Featuring instruments such as Spitzer, Herschel, Fermi, ALMA, Super-Kamiokande, SNO, IceCube, the Auger Observatory, LIGO and LISA, the book discusses the capabilities and limitations of different types of instruments. It explores the sources and types of noise and provides statistical tools necessary for interpreting observational data. Due to the increasingly important role of statistical analysis, the techniques of Bayesian analysis are discussed, along with sampling techniques and model comparison. With topics ranging from fundamental subjects such as optics, photometry and spectroscopy, to neutrinos, cosmic rays and gravitational waves, this book is essential for graduate students in astronomy and physics. Electronic and colour versions of selected figures are available online at www. cambridge.org/9781107010468.
Download or read book Single Photon Generation and Detection written by Karl K. Berggren and published by Elsevier Inc. Chapters. This book was released on 2013-11-29 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: Superconducting materials provide a unique opportunity for single-photon detectors. The combination of the strong non-linearity present in the superconducting-metal transition and in Josephson junctions; the unique electrical property of zero resistance; the fast relaxation processes present in many superconducting materials; and the easily engineered optical absorptance of metals results in a system that can be adapted to many photo-detection requirements. As a result of these material features, a variety of detector families have emerged in recent years based on superconducting nanowires, tunnel junctions, weak thermal links, and kinetic-inductive resonators. The detectors variously provide high speed single-photon detection; high-sensitivity in the infrared, optical, UV, or even x-ray wavelengths; and high efficiency. The resulting applications include quantum and classical high-data-rate communication, biological imaging, LIDAR, and VLSI circuit evaluation among others.
Download or read book New Horizons for Observational Cosmology written by A. Cooray and published by IOS Press. This book was released on 2015-01-06 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our understanding of the universe has been revolutionized by observations of the cosmic microwave background, the large-scale structure of the universe, and distant supernovae. These studies have shown that we are living in a strange universe: 96% of the present day energy density of the universe is dominated by so-called dark matter and dark energy. But we still do not know what dark matter and dark energy actually are. This book presents lectures from the 186th Course in the Enrico Fermi International School of Physics entitled New Horizons for Observational Cosmology, held in Varenna, Italy, in July 2013. Topics covered at this school included: cosmic microwave background anisotropies; galaxy clustering; weak lensing; dark energy; dark matter; inflation; modified gravity; neutrino physics; reionization; galaxy formation; and first stars. The anticipated release of Planck data at the end of 2014 will provide a more complete view of temperature anisotropy of the cosmic microwave background, and the reporting of other important results is also expected soon. These new data will undoubtedly address fundamental questions about the universe. This book prepares the ground for future work which may answer some of these exciting questions.
Download or read book Radiative Processes in Astrophysics written by George B. Rybicki and published by John Wiley & Sons. This book was released on 2008-09-26 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radiative Processes in Astrophysics: This clear, straightforward, and fundamental introduction is designed to present-from a physicist's point of view-radiation processes and their applications to astrophysical phenomena and space science. It covers such topics as radiative transfer theory, relativistic covariance and kinematics, bremsstrahlung radiation, synchrotron radiation, Compton scattering, some plasma effects, and radiative transitions in atoms. Discussion begins with first principles, physically motivating and deriving all results rather than merely presenting finished formulae. However, a reasonably good physics background (introductory quantum mechanics, intermediate electromagnetic theory, special relativity, and some statistical mechanics) is required. Much of this prerequisite material is provided by brief reviews, making the book a self-contained reference for workers in the field as well as the ideal text for senior or first-year graduate students of astronomy, astrophysics, and related physics courses. Radiative Processes in Astrophysics also contains about 75 problems, with solutions, illustrating applications of the material and methods for calculating results. This important and integral section emphasizes physical intuition by presenting important results that are used throughout the main text; it is here that most of the practical astrophysical applications become apparent.
Download or read book Single Photon Generation and Detection written by and published by Academic Press. This book was released on 2013-11-29 with total page 593 pages. Available in PDF, EPUB and Kindle. Book excerpt: Single-photon generation and detection is at the forefront of modern optical physics research. This book is intended to provide a comprehensive overview of the current status of single-photon techniques and research methods in the spectral region from the visible to the infrared. The use of single photons, produced on demand with well-defined quantum properties, offers an unprecedented set of capabilities that are central to the new area of quantum information and are of revolutionary importance in areas that range from the traditional, such as high sensitivity detection for astronomy, remote sensing, and medical diagnostics, to the exotic, such as secretive surveillance and very long communication links for data transmission on interplanetary missions. The goal of this volume is to provide researchers with a comprehensive overview of the technology and techniques that are available to enable them to better design an experimental plan for its intended purpose. The book will be broken into chapters focused specifically on the development and capabilities of the available detectors and sources to allow a comparative understanding to be developed by the reader along with and idea of how the field is progressing and what can be expected in the near future. Along with this technology, we will include chapters devoted to the applications of this technology, which is in fact much of the driver for its development. This is set to become the go-to reference for this field. - Covers all the basic aspects needed to perform single-photon experiments and serves as the first reference to any newcomer who would like to produce an experimental design that incorporates the latest techniques - Provides a comprehensive overview of the current status of single-photon techniques and research methods in the spectral region from the visible to the infrared, thus giving broad background that should enable newcomers to the field to make rapid progress in gaining proficiency - Written by leading experts in the field, among which, the leading Editor is recognized as having laid down the roadmap, thus providing the reader with an authenticated and reliable source
Download or read book Development of Coherent Detector Technologies for Sub Millimetre Wave Astronomy Observations written by Boon Kok Tan and published by Springer. This book was released on 2015-09-15 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: The thesis describes the development of receiver technologies for sub-millimetre astronomy instruments, focusing on high performance coherent cryogenic detectors operating close to the superconductor gap frequency. The mixer chip which comprises the SIS devices, fed by a unilateral finline and matching planar circuits was fabricated on 15 micron silicon substrate using the recently developed Silicon-On-Insulator (SOI) technology. This offered broadband IF and RF performance, with fully integrated on-chip planar circuits resulting in an easily reproducible mixer chip and a simple mixer block. An important consequence of this design is that it can be extended to the supra-THz region and making the fabrication of multi-pixel heterodyne arrays feasible. The extension of the operation of major telescopes such as ALMA, APEX and the GLT from single pixel to large format arrays is the subject of extensive research at present time since it will allow fast mapping combined with high resolution of the submillimetre sky. The technology described in this thesis makes a major contribution to this effort.
Download or read book Cosmological Probes of Light Relics written by Benjamin Wallisch and published by Springer Nature. This book was released on 2019-11-20 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: The wealth of recent cosmic microwave background and large-scale structure data has transformed the field of cosmology. These observations have not only become precise enough to answer questions about the universe on the largest scales, but also to address puzzles in the microscopic description of Nature. This thesis investigates new ways of probing the early universe, the properties of neutrinos and the possible existence of other light particles. In particular, based on detailed theoretical insights and novel analyses, new evidence for the cosmic neutrino background is found in the distribution of galaxies and in cosmic microwave background data. This tests the Standard Model of particle physics and the universe back to a time when it was about one second old. Furthermore, it is demonstrated that future observations will be capable of probing physics beyond the Standard Model since they can achieve a particular target which would either allow the detection of any light particles that have ever been in thermal equilibrium or imply strong bounds on their properties.
Download or read book Cryogenic Particle Detection written by Hans-Christian Stahl and published by Springer Science & Business Media. This book was released on 2005-06-22 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of cryogenic devices for particle detection has reached a stage at which many interesting applications are conceivable and already have been demonstrated. The book provides a comprehensive review of the field of cryogenic particle detection. It introduces the different detection techniques and gives an overview of the important areas in which these detectors are successfully applied.
