Author: Darin Shawn KinionPublisher:
ISBN:
Category :
Languages : en
Pages : 378
Book Description
First Results from a Multiple-microwave-cavity Search for Dark-matter Axions
Microwave Cavities for Axion Dark Matter Detectors
Author: Ian SternPublisher: Dissertation Discovery Company
ISBN: 9780530000046
Category :
Languages : en
Pages : 202
Book Description
Dissertation Discovery Company and University of Florida are dedicated to making scholarly works more discoverable and accessible throughout the world. This dissertation, "Microwave Cavities for Axion Dark Matter Detectors" by Ian Phillip Stern, was obtained from University of Florida and is being sold with permission from the author. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. Abstract: Nearly all astrophysical and cosmological data point convincingly to a large component of cold dark matter (CDM) in the Universe. The axion particle, first theorized as a solution to the strong charge-conjugate/parity problem of quantum chromodynamics, has been established as a prominent CDM candidate. Cosmic observation and particle physics experiments have bracketed the unknown mass of such CDM axions between approximately microelectronvolts and millielectronvolts. The Axion Dark Matter eXperiment (ADMX) is a direct-detection CDM axion search which has set limits at the KSVZ coupling of the axion to two photons for axion masses between 1.9 and 3.7 microelectronvolts. But most of the viable search-space of axions has yet to be probed. It is now evident that the current cavity design for ADMX does not provide for successful scanning above 4 microelectronvolts ( 1 gigahertz), and new microwave cavity technologies need to be developed to enable searching for CDM axions of greater mass. A broad study into factors that affect high-frequency microwave cavity was conducted in an effort to expand the capabilities of current haloscope detectors. The study evaluated the effects of symmetry breaking on axion search potential and assessed state-of-the-art cavity technologies relevant to haloscope detectors. Periodic arrays of tuning rods or vanes were evaluated for increasing the search range of haloscopes, and a prototype haloscope cavity and an in-situ mode identification technique were developed and tested. The study revealed several significant findings. The cause for frequency gaps in search modes at mode crossing is mode mixing, which occurs due to longitudinal symmetry breaking. Symmetry breaking also results in increased mode crowding, which hinders mode identification and tracking, and further increases mode mixing. Arrays of tuning rods or vanes produce tunable modes, but result in increased sensitivity to symmetry breaking, requiring advanced mode identification techniques and additional studies.
Second-generation Dark-matter Axion Search
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 12
Book Description
This research project is a collaboration with the axion search experiment at Lawrence Livermore National Laboratory. The axion is a particle that affects two important issues in particle physics and astrophysics: the origin of CP symmetry in the strong interactions, and the composition of the dark-matter of the universe. First predicted in 1978, present laboratory, astrophysical, and cosmological constraints suggest axions have a mass in the 1 [mu]eV-1 meV range. Axions are especially significant as dark matter if their mass is in the range 1-10 [mu]eV. These dark matter axions may be detected by their coupling to photons through the E - B interaction in a tunable high-Q microwave cavity permeated by a strong external magnetic field. The present experiment is the first cavity experiment with the sensitivity to possibly observe cosmic axions. It has recently begun taking data and will operate for the next several years. The University of Florida plans to contribute to the operation of this detector and to the design and prototyping of cavities for the experiment.
A SQUID-based RF Cavity Search for Dark Matter Axions
Author: Michael T. HotzPublisher:
ISBN:
Category : Axions
Languages : en
Pages : 165
Book Description
The axion is a hypothetical elementary particle resulting from a solution to the "Strong-CP" problem. This serious problem in the standard model of particle physics is manifested as a 1010 discrepancy between the measured upper limit and the calculated value of the neutron's electric dipole moment. Furthermore, a light (~ [mu] eV) axion is an ideal dark matter candidate: axions would have been copiously produced during the Big Bang and would be the primary component of the dark matter in the universe. The resolution of the Strong-CP problem and the discovery of the composition of dark matter are two of the most pressing problems in physics. The observation of a light, dark-matter axion would resolve both of these problems. The Axion Dark Matter eXperiment (ADMX) is the most sensitive search for dark-matter axions. Axions in our Milky Way Galaxy may scatter off a magnetic field and convert into microwave photons. ADMX consists of a tunable high-Q RF cavity within the bore of a large, 8.5 Tesla superconducting solenoidal magnet. When the cavity's resonant frequency matches the axion's total energy, the probability of axion-to-photon conversion is enhanced. The cavity's narrow bandwidth requires ADMX to slowly scan possible axion masses. A receiver amplifies, mixes, and digitizes the power developed in the cavity from possible axion-to-photon conversions. This is the most sensitive spectral receiver of microwave radiation in the world. The resulting data is scrutinized for an axion signal above the thermal background. ADMX first operated from 1995-2005 and produced exclusion limits on the energy of dark-matter axions from 1.9 [mu] eV to 3.3 [mu] eV. In order to improve on these limits and continue the search for plausible dark-matter axions, the system was considerably upgraded from 2005 until 2008. In the upgrade, the key technical advance was the use of a dc Superconducting QUantum Interference Device (SQUID) as a microwave amplifier. The SQUID amplifier's noise level is near the allowed minimum from quantum mechanics, allowing ADMX to reduce its thermal noise background by up to 100x. However, SQUIDs are extremely sensitive to magnetic fields, such as those within in ADMX. Integrating a SQUID amplifier into ADMX presented a serious technical challenge. Commissioning the SQUID amplifier was a major focus of my thesis work. This work demonstrates the successful use of a SQUID amplifier in ADMX during operations from 2008-2010. Compared to other dark-matter candidates, the axion's mass and the axion's coupling strength to normal matter and radiation are rather tightly constrained. This allows for the near-definitive elimination or detection of dark-matter axions. A successful detection in ADMX would immediately lead to a determination of the axion's spectral line shape. This shape encodes the history of the Milky Way's formation and is therefore of high scientific importance. The imperfectly-constrained Milky Way dark-matter halo, however, produces remnant uncertainties of the axion signal in both its spectral line-shape and its total intensity, complicating the ADMX search. This work investigates proposed features of dark-matter halo models which enhance ADMX's sensitivity. From these models, this work presents the corresponding exclusion limits for both the local axion density and axion-to-photon coupling strength for axions with mass in the 3.36 [mu] eV to 3.69 [mu] eV region.
Application of Bead-Perturbation Field Mapping to the Microwave Cavity Search for Dark Matter Axions
Author: Jaben Robert RootMicrowave Cavities and Detectors for Axion Research
Author: Gianpaolo CarosiPublisher: Springer Nature
ISBN: 3030437612
Category : Science
Languages : en
Pages : 173
Book Description
The nature of dark matter remains one of the preeminent mysteries in physics and cosmology. It appears to require the existence of new particles whose interactions with ordinary matter are extraordinarily feeble. One well-motivated candidate is the axion, an extraordinarily light neutral particle that may possibly be detected by looking for their conversion to detectable microwaves in the presence of a strong magnetic field. This has led to a number of experimental searches that are beginning to probe plausible axion model space and may reveal the axion in the near future. These proceedings discuss the challenges of designing and operating tunable resonant cavities and detectors at ultralow temperatures. The topics discussed here have potential application far beyond the field of dark matter detection and may be applied to resonant cavities for accelerators as well as designing superconducting detectors for quantum information and computing applications. This work is intended for graduate students and researchers interested in learning the unique requirements for designing and operating microwave cavities and detectors for direct axion searches and to introduce several proposed experimental concepts that are still in the prototype stage.
Axions
Author: Markus KusterPublisher: Springer
ISBN: 3540735186
Category : Science
Languages : en
Pages : 248
Book Description
Axions are peculiar hypothetical particles that could both solve the CP problem of quantum chromodynamics and at the same time account for the dark matter of the universe. Based on a series of lectures by world experts in this field held at CERN (Geneva), this volume provides a pedagogical introduction to the theory, cosmology and astrophysics of these fascinating particles and gives an up-to-date account of the status and prospect of ongoing and planned experimental searches.
Large-scale Search for Dark-matter Axions
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 6
Book Description
Early results from a large-scale search for dark matter axions are presented. In this experiment, axions constituting our dark-matter halo may be resonantly converted to monochromatic microwave photons in a high-Q microwave cavity permeated by a strong magnetic field. Sensitivity at the level of one important axion model (KSVZ) has been demonstrated.
Status of the Large-scale Dark-matter Axion Search
Author: A Piezoelectrically Tuned RF-cavity Search for Dark Matter Axions
Author: Christian BoutanPublisher:
ISBN:
Category : Axions
Languages : en
Pages : 155
Book Description
The Axion is a well motivated hypothetical elementary particle that must exist in nature if the strong CP problem of QCD is explained by the spontaneous breaking of a Peccei-Quinn symmetry. Not only would the discovery of the axion solve deep issues in QCD, an axion with a mass of [mu]eV - meV could account for most or all of the missing mass in our galaxy and finally reveal the composition of dark matter. The Axion Dark Matter experiment (ADMX) seeks to resolve these two critical problems in physics by looking for the resonant conversion of dark-matter axions to microwave photons in a strong magnetic field. Utilizing state of the art electronics and dilution refrigerator cryogenics, ADMX is the world's leading haloscope search for axions - able to discover or rule out even the most pessimistically coupled QCD axions. With multi-TM0N0 functionality and with the commissioning of the new high-frequency Sidecar experiment, ADMX is also sensitive to a wide range of plausible axion masses. Here I motivate axions as ideal dark matter candidates, review techniques for detecting them and give a detailed description of the ADMX experiment. I discuss my contributions to the construction of the ADMX dual-channel receiver, which is the most sensitive microwave receiver on earth. I discuss the data acquisition, data taking and real-time analysis software. The primary focus of this work, however, is the ADMX Sidecar experiment which is a miniature axion haloscope that fits inside of the ADMX insert and has the capability of searching for axion masses between 16[mu]eV - 24[mu]eV on the TM010 and 26.4 - 30[mu]eV on the TM020 mode. I discuss analysis of the Sidecar data and exclude axion-to-two-photon coupling g[alpha] [gamma] [gamma]