|
ADMX Axion Parameter Space Exclusion 2021
The Axion Dark Matter Experiment (ADMX, also written as ''Axion Dark Matter eXperiment'' in the project's documentation) is an experiment that uses a resonant microwave cavity within a large superconducting magnet to search for cold dark matter axions in the local galactic dark matter halo. Unusual for a dark matter detector, it is not located deep underground. Sited at the Center for Experimental Nuclear Physics and Astrophysics (CENPA) at the University of Washington, ADMX is a large collaborative effort with researchers from universities and laboratories around the world. Background The axion is a hypothetical elementary particle originally postulated to solve the strong CP problem. The axion is also an extremely attractive dark matter candidate. The axion is the puzzle piece allowing these two mysteries to fit naturally into our understanding of the universe. Strong CP problem The axion was originally postulated to exist as part of the solution to the "strong CP problem". T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microwave Cavity
A microwave cavity or radio frequency cavity (RF cavity) is a special type of resonator, consisting of a closed (or largely closed) metal structure that confines electromagnetic fields in the microwave or radio frequency, RF region of the spectrum. The structure is either hollow or filled with dielectric material. The microwaves bounce back and forth between the walls of the cavity. At the cavity's resonant frequency, resonant frequencies they reinforce to form standing waves in the cavity. Therefore, the cavity functions similarly to an organ pipe or sound box in a musical instrument, oscillating preferentially at a series of frequencies, its resonant frequencies. Thus it can act as a bandpass filter, allowing microwaves of a particular frequency to pass while blocking microwaves at nearby frequencies. A microwave cavity acts similarly to a resonant circuit with extremely low loss at its frequency of operation, resulting in quality factors (Q factors) up to the order of 106, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Florida
The University of Florida (Florida or UF) is a public university, public land-grant university, land-grant research university in Gainesville, Florida, United States. It is a senior member of the State University System of Florida and a preeminent university in the state. The university traces its origins to 1853 and has operated continuously on its Gainesville campus since September 1906. After the Florida state legislature's creation of performance standards in 2013, the Florida Board of Governors designated the University of Florida as a "preeminent university". The University of Florida is one of three members of the Association of American Universities in Florida and is Carnegie Classification of Institutions of Higher Education, classified among "R1: Doctoral Universities – Very high research spending and doctorate production". The university is Higher education accreditation in the United States, accredited by the Southern Association of Colleges and Schools (SACS). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yale University
Yale University is a Private university, private Ivy League research university in New Haven, Connecticut, United States. Founded in 1701, Yale is the List of Colonial Colleges, third-oldest institution of higher education in the United States, and one of the nine colonial colleges chartered before the American Revolution. Yale was established as the Collegiate School in 1701 by Congregationalism in the United States, Congregationalist clergy of the Connecticut Colony. Originally restricted to instructing ministers in theology and sacred languages, the school's curriculum expanded, incorporating humanities and sciences by the time of the American Revolution. In the 19th century, the college expanded into graduate and professional instruction, awarding the first Doctor of Philosophy, PhD in the United States in 1861 and organizing as a university in 1887. Yale's faculty and student populations grew rapidly after 1890 due to the expansion of the physical campus and its scientif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noise Temperature
In electronics, noise temperature is one way of expressing the level of available noise power introduced by a component or source. The power spectral density of the noise is expressed in terms of the temperature (in kelvins) that would produce that level of Johnson–Nyquist noise, thus: :\frac = k_\text T where: * P_\text is the noise power (in W, watts) * B is the total bandwidth (Hz, hertz) over which that noise power is measured * k_\text is the Boltzmann constant (, joules per kelvin) * T is the noise temperature (K, kelvin) Thus the noise temperature is proportional to the power spectral density of the noise, P_\text/ B. That is the power that would be absorbed from the component or source by a matched load. Noise temperature is generally a function of frequency, unlike that of an ideal resistor which is simply equal to the actual temperature of the resistor at all frequencies. Noise voltage and current A noisy component may be modelled as a noiseless component i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HFET
A high-electron-mobility transistor (HEMT or HEM FET), also known as heterostructure FET (HFET) or modulation-doped FET (MODFET), is a field-effect transistor incorporating a junction between two materials with different band gaps (i.e. a heterojunction) as the channel instead of a doped region (as is generally the case for a MOSFET). A commonly used material combination is GaAs with AlGaAs, though there is wide variation, dependent on the application of the device. Devices incorporating more indium generally show better high-frequency performance, while in recent years, gallium nitride HEMTs have attracted attention due to their high-power performance. Like other FETs, HEMTs can be used in integrated circuits as digital on-off switches. FETs can also be used as amplifiers for large amounts of current using a small voltage as a control signal. Both of these uses are made possible by the FET’s unique current–voltage characteristics. HEMT transistors are able to operate at hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ADMX Magnet Installation
The Axion Dark Matter Experiment (ADMX, also written as ''Axion Dark Matter eXperiment'' in the project's documentation) is an experiment that uses a resonant microwave cavity within a large superconducting magnet to search for cold dark matter axions in the local galactic dark matter halo. Unusual for a dark matter detector, it is not located deep underground. Sited at the Center for Experimental Nuclear Physics and Astrophysics (CENPA) at the University of Washington, ADMX is a large collaborative effort with researchers from universities and laboratories around the world. Background The axion is a hypothetical elementary particle originally postulated to solve the strong CP problem. The axion is also an extremely attractive dark matter candidate. The axion is the puzzle piece allowing these two mysteries to fit naturally into our understanding of the universe. Strong CP problem The axion was originally postulated to exist as part of the solution to the "strong CP problem". T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SQUID
A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also called ''squid'' despite not strictly fitting these criteria). Like all other cephalopods, squid have a distinct head, Symmetry (biology)#Bilateral symmetry, bilateral symmetry, and a mantle (mollusc), mantle. They are mainly soft-bodied, like octopuses, but have a small internal skeleton in the form of a rod-like gladius (cephalopod), gladius or pen, made of chitin. Squid diverged from other cephalopods during the Jurassic and occupy a similar Ecological niche, role to teleost fish as open-water predators of similar size and behaviour. They play an important role in the open-water food web. The two long tentacles are used to grab prey and the eight arms to hold and control it. The beak then cuts the food into suitable size chunks for swal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactic Halo
A galactic halo is an extended, roughly spherical component of a galaxy which extends beyond the main, visible component. Several distinct components of a galaxy comprise its halo: * the stellar halo * the galactic corona (hot gas, i.e. a plasma) * the dark matter halo The distinction between the halo and the main body of the galaxy is clearest in spiral galaxies, where the spherical shape of the halo contrasts with the flat disc. In an elliptical galaxy, there is no sharp transition between the other components of the galaxy and the halo. A halo can be studied by observing its effect on the passage of light from distant bright objects like quasars that are in line of sight beyond the galaxy in question. Components of the galactic halo Stellar halo The stellar halo is a nearly spherical population of field stars and globular clusters. It surrounds most disk galaxies as well as some elliptical galaxies of type cD. A low amount (about one percent) of a galaxy's stellar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milky Way
The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galaxy, which are so far away that they cannot be individually distinguished by the naked eye. The Milky Way is a barred spiral galaxy with a Galaxy#Isophotal diameter, D25 isophotal diameter estimated at , but only about 1,000 light-years thick at the spiral arms (more at the bulge). Recent simulations suggest that a dark matter area, also containing some visible stars, may extend up to a diameter of almost 2 million light-years (613 kpc). The Milky Way has several List of Milky Way's satellite galaxies, satellite galaxies and is part of the Local Group of galaxies, forming part of the Virgo Supercluster which is itself a component of the Laniakea Supercluster. It is estimated to contain 100–400 billion stars and at least that number of pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tesla (unit)
The tesla (symbol: T) is the unit of magnetic flux density (also called magnetic B-field strength) in the International System of Units (SI). One tesla is equal to one weber per square metre. The unit was announced during the General Conference on Weights and Measures in 1960 and is named in honour of Serbian-American electrical and mechanical engineer Nikola Tesla, upon the proposal of the Slovenian electrical engineer France Avčin. Definition A particle, carrying a charge of one coulomb (C), and moving perpendicularly through a magnetic field of one tesla, at a speed of one metre per second (m/s), experiences a force with magnitude one newton (N), according to the Lorentz force law. That is, \mathrm. As an SI derived unit, the tesla can also be expressed in terms of other units. For example, a magnetic flux of 1 weber (Wb) through a surface of one square meter is equal to a magnetic flux density of 1 tesla.''The International System of Units (SI), 8th edition' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BBC Two
BBC Two is a British free-to-air Public service broadcasting in the United Kingdom, public broadcast television channel owned and operated by the BBC. It is the corporation's second flagship channel, and it covers a wide range of subject matter, incorporating genres such as comedy, drama and documentaries. BBC Two has a remit "to broadcast highbrow, programmes of depth and substance" in contrast to the more mainstream and popular BBC One. Like the BBC's other domestic TV and radio channels, it is funded by the television licence, and is therefore free of commercial advertising. It is a comparatively well-funded Public broadcasting, public-service channel, regularly attaining a much higher audience share than most public-service channels worldwide. Originally styled BBC2, it was the third British television station to be launched (starting on 21 April 1964), and from 1 July 1967, Europe's first television channel to broadcast regularly in colour. It was envisaged as a home for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horizon (British TV Series)
''Horizon'' is an ongoing and long-running British documentary film, documentary television series on BBC Two that covers science and philosophy. History The programme was first broadcast on 2 May 1964 with "The World of Buckminster Fuller", which explored the theories and structures of inventor Buckminster Fuller, Richard Buckminster Fuller and included the ''Horizon'' mission statement: "The aim of ''Horizon'' is to provide a platform from which some of the world's greatest scientists and philosophers can communicate their curiosity, observations and reflections, and infuse into our common knowledge their changing views of the universe". ''Horizon'' continues to be broadcast on BBC Two, and in 2009 added a series of films based on the rich ''Horizon'' archive, called ''Horizon Guides'', on BBC Four. In December 2016, it was announced that ''Horizon'' would no longer be made exclusively by the BBC's in-house production division, BBC Studios, and the BBC invited independent produ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
