A Proposed Search for Dark-matter Axions in the 0. 6--16. Mu. EV Range PDF Download
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Author: Publisher: ISBN: Category : Languages : en Pages : 13
Book Description
A proposed experiment is described to search for dark-matter axions in the mass range 0.6--16 [mu]eV. The method is based on the Primakoff conversion of axions into monochromatic microwave photons inside a tunable microwave cavity in a large volume high field magnet, as described by Sikivie. This proposal capitalizes on the availability of two Axicell magnets from the decommissioned MFTF-B fusion machine at LLNL. Assuming a local dark-matter density in axions of [rho] = 0.3 GeV/cm3, the axion would be found or ruled out at the 97% c.l. in the above mass range in 48 months. 13 refs., 6 figs., 2 tabs.
Author: Publisher: ISBN: Category : Languages : en Pages : 13
Book Description
A proposed experiment is described to search for dark-matter axions in the mass range 0.6--16 [mu]eV. The method is based on the Primakoff conversion of axions into monochromatic microwave photons inside a tunable microwave cavity in a large volume high field magnet, as described by Sikivie. This proposal capitalizes on the availability of two Axicell magnets from the decommissioned MFTF-B fusion machine at LLNL. Assuming a local dark-matter density in axions of [rho] = 0.3 GeV/cm3, the axion would be found or ruled out at the 97% c.l. in the above mass range in 48 months. 13 refs., 6 figs., 2 tabs.
Author: Christian Boutan Publisher: 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]
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
Here, we show that dark matter axions cause an oscillating electric current to flow along magnetic field lines. The oscillating current induced in a strong magnetic field B→ 0 produces a small magnetic field B→ a. We propose to amplify and detect B→ a using a cooled LC circuit and a very sensitive magnetometer. This appears to be a suitable approach to searching for axion dark matter in the 10-7 to 10-9 eV mass range.
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.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
We describe the status of a sensitive search for halo axions with masses in the [mu]eV range. A tunable large-volume and low-loss microwave cavity is operated at low temperature in a strong magnetic field. Resonant Primakoff conversion of axions into photons takes place when the cavity frequency is matched to the axion mass. No positive signal has been found so far, and we are able to exclude hadronic axions as the dominant halo component over a significant axion mass range. Future plans for a detector upgrade are outlined.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
If axions constitute the dark matter of our galactic halo they can be detected by their conversion into monochromatic microwave photons in a high-Q microwave cavity permeated by a strong magnetic field. A large-scale experiment is under construction at LLNL to search for halo axions in the mass range 1.3 - 13[mu]eV, where axions may constitute closure density of the universe. The search builds upon two pilot efforts at BNL and the University of Florida in the late 1980's, and represents a large improvement in power sensitivity ([approximately]50) both due to the increase in magnetic volume (B[sup 2]V= 14 T[sup 2]m[sup 3]), and anticipated total noise temperature (T[sub n][approximately]3K). This search will also mark the first use of multiple power-combined cavities to extend the mass range accessible by this technique. Data will be analyzed in two parallel streams. In the first, the resolution of the power spectrum will be sufficient to resolve the expected width of the overall axion line, [approximately][bigcirc] (1kHz). In the second, the resolution will be[bigcirc](O.01-1 Hz) to look for extremely narrow substructure reflecting the primordial phase-space of the axions during infall. This experiment will be the first to have the required sensitivity to detect axions, for plausible axion models.
Author: Nick Chong Du Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
The axion is a hypothetical elementary particle that came out of a solution to the Strong-CP problem in Quantum Chromodynamics (QCD). The properties of the axion also make it a highly compelling candidate for dark matter. Axion haloscopes are instruments that search for axion dark matter in the local Milky Way halo by searching for the conversion of an axion into photons via the inverse Primakoff effect. The Axion Dark Matter eXperiment (ADMX) is by far the most sensitive axion haloscope, being the first to exclude benchmark models for the QCD axion and continuing to take data at high sensitivity. This thesis reports on a run by ADMX which excluded dark matter axions in the galactic halo over the mass range 2.81--3.31[mu]eV. This unprecedented sensitivity in this mass range is achieved by deploying an ultra low-noise Josephson parametric amplifier as the first-stage signal amplifier.
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Author: Christian Boutan
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Author: Nick Chong Du