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The Gamma-ray Transients Monitor
Gamma-ray Transients Monitor (GTM) is the first Space telescope, space astronomical telescope of Taiwan. It is a secondary payload on board Formosat-8B (FS-8B), which is a Remote sensing satellites, remote-sensing satellite developed by Taiwan Space Agency, TASA. The goal of GTM is to track Gamma-ray burst, Gamma Ray Bursts (GRBs) and other bright gamma-ray transients with energies ranging from 50 keV to 2 MeV. GTM is made up of two identical modules on opposite sides of the FS-8B. Each module has four sensor units facing different directions, covering half of the sky. The two modules will then cover the entire sky, including the direction obscured by the Earth. The sensor units consist of a Gadolinium gallium garnet, Gadolinium Aluminum Gallium Garnet (GAGG) (a semiconductor) scintillator array (50 mm x 50 mm x 8 mm) that is readout by Silicon photomultiplier, SiPM with 16 pixel channels. GTM is expected to detect approximately 50 GRBs per year. It is expected to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watt
The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work (physics), energy transfer. The watt is named in honor of James Watt (1736–1819), an 18th-century Scottish people, Scottish inventor, mechanical engineer, and chemist who improved the Newcomen engine with his own Watt steam engine, steam engine in 1776, which became fundamental for the Industrial Revolution. Overview When an object's velocity is held constant at one meter per second against a constant opposing force of one Newton (unit), newton, the rate at which Work (physics), work is done is one watt. \mathrm. In terms of electromagnetism, one watt is the rate at which electrical work is performed when a current of one ampere (A) flows across an electrical potential difference of one volt (V), meaning the watt is equivalent to the vo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon Photomultiplier
In solid-state electronics, silicon photomultipliers (SiPMs) are single-photon-sensitive devices based on pixels of single-photon avalanche diodes (SPADs) implemented on common silicon substrate. The dimension of each single avalanche diode can vary from 10 to 100 micrometres, with a typical density of up to 1,000 pixels/mm2. Every avalanche diode in a SiPM operates in Geiger mode and is coupled with the others by a metal or polysilicon quenching resistor. Although the device works in digital/switching mode, most SiPMs are analog devices because the microcells are read in parallel, making it possible to generate signals with a dynamic range from a single photon to 1000 photons for a device with just a square-millimeter area. More advanced readout schemes are used for lidar applications. The supply voltage () depends on the APD technology used and typically varies between 20 V and 100 V, thus being from 15 to 75 times lower than the voltage required for traditional photomultiplie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma-ray Telescopes
A gamma ray, also known as gamma radiation (symbol ), is a penetrating form of electromagnetic radiation arising from high energy interactions like the radioactive decay of atomic nuclei or astronomical events like solar flares. It consists of the shortest wavelength electromagnetic waves, typically shorter than those of X-rays. With frequencies above 30 exahertz () and wavelengths less than 10 picometers (), gamma ray photons have the highest photon energy of any form of electromagnetic radiation. Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900 while studying radiation emitted by radium. In 1903, Ernest Rutherford named this radiation ''gamma rays'' based on their relatively strong penetration of matter; in 1900, he had already named two less penetrating types of decay radiation (discovered by Henri Becquerel) alpha rays and beta rays in ascending order of penetrating power. Gamma rays from radioactive decay are in the energy r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Telescopes Orbiting Earth
Space is a three-dimensional continuum containing positions and directions. In classical physics, physical space is often conceived in three linear dimensions. Modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum known as ''spacetime''. The concept of space is considered to be of fundamental importance to an understanding of the physical universe. However, disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework. In the 19th and 20th centuries mathematicians began to examine geometries that are non-Euclidean, in which space is conceived as '' curved'', rather than '' flat'', as in the Euclidean space. According to Albert Einstein's theory of general relativity, space around gravitational fields deviates from Euclidean space. Experimental tests of general relativity have confirmed that non-Euclidean geometries provide a better model ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redshift
In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and energy, is known as a #Blueshift, blueshift. The terms derive from the colours red and blue which form the extremes of the Visible spectrum, visible light spectrum. Three forms of redshift occur in astronomy and cosmology: Doppler effect, Doppler redshifts due to the relative motions of radiation sources, gravitational redshift as radiation escapes from gravitational potentials, and cosmological redshifts of all light sources proportional to their distances from Earth, a fact known as Hubble's law that implies the expansion of the universe, universe is expanding. All redshifts can be understood under the umbrella of Frame of reference, frame transformation laws. Gravitational waves, which also travel at Speed of light, the speed of light, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Ia Supernova
A Type Ia supernova (read: "type one-A") is a type of supernova that occurs in binary systems (two stars orbiting one another) in which one of the stars is a white dwarf. The other star can be anything from a giant star to an even smaller white dwarf. Physically, carbon–oxygen white dwarfs with a low rate of rotation are limited to below 1.44 solar masses (). Beyond this "Chandrasekhar limit, critical mass", they reignite and in some cases trigger a supernova explosion; this critical mass is often referred to as the Chandrasekhar mass, but is marginally different from the absolute Chandrasekhar limit, where electron degeneracy pressure is unable to prevent catastrophic collapse. If a white dwarf gradually accretes mass from a binary companion, or merges with a second white dwarf, the general hypothesis is that a white dwarf's core will reach the ignition temperature for Carbon burning process, carbon fusion as it approaches the Chandrasekhar mass. Within a few seconds of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmic Distance Ladder
The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects. A ''direct'' distance measurement of an astronomical object is possible only for those objects that are "close enough" (within about a thousand parsecs or 3e16 km) to Earth. The techniques for determining distances to more distant objects are all based on various measured correlations between methods that work at close distances and methods that work at larger distances. Several methods rely on a ''standard candle'', which is an astronomical object that has a known luminosity. The ladder analogy arises because no single technique can measure distances at all ranges encountered in astronomy. Instead, one method can be used to measure nearby distances, a second can be used to measure nearby to intermediate distances, and so on. Each rung of the ladder provides information that can be used to determine the distan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Academia Sinica
Academia Sinica (AS, ; zh, t=中央研究院) is the national academy of the Taiwan, Republic of China. It is headquartered in Nangang District, Taipei, Nangang, Taipei. Founded in Nanjing, the academy supports research activities in mathematics, Physical Sciences, physical sciences, Life Sciences, life sciences, humanities and social sciences. As an educational institute, it provides PhD training and scholarship through its English-language Taiwan International Graduate Program in biology, agriculture, chemistry, physics, informatics, and Earth and Environmental Sciences, earth and environmental sciences. The current president since 2016 is James C. Liao, an expert in metabolic engineering, systems biology and synthetic biology. History Academia Sinica, which means "Chinese Academy", was founded in 1928 in Nanjing, then capital of the Republic of China (1912–1949), Republic of China, with its first meeting held in Shanghai. By December 1948, all fourteen institutes of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Tsing Hua University
National Tsing Hua University (NTHU) is a public research university in Hsinchu, Taiwan. It was first founded in Beijing. After the Chinese Civil War, president Mei Yiqi and other academics relocated with the retreating Nationalist government to Taiwan, where they reestablished National Tsing Hua University in 1956. The university remains independent and distinct from Tsinghua University in Beijing. The university is part of a leading research and innovation cluster in Taiwan, along with nearby National Yang Ming Chiao Tung University, National Space Organization, National Health Research Institutes, Industrial Technology Research Institute, National Synchrotron Radiation Research Center, National Center for High-Performance Computing, Taiwan Semiconductor Research Institute, and Industrial Technology Research Institute. The research cluster and its neighboring Hsinchu Science Park together play a key role in the global semiconductor industry. There are 12 colleges or sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scintillator
A scintillator ( ) is a material that exhibits scintillation, the property of luminescence, when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate (i.e. re-emit the absorbed energy in the form of light). Sometimes, the excited state is metastable, so the relaxation back down from the excited state to lower states is delayed (necessitating anywhere from a few nanoseconds to hours depending on the material). The process then corresponds to one of two phenomena: delayed fluorescence or phosphorescence. The correspondence depends on the type of transition and hence the wavelength of the emitted optical photon. Principle of operation A scintillation detector or scintillation counter is obtained when a scintillator is coupled to an electronic light sensor such as a photomultiplier tube (PMT), photodiode, or silicon photomultiplier. PMTs absorb the light emitted by the scintillator and re-emit it in the form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semiconductor
A semiconductor is a material with electrical conductivity between that of a conductor and an insulator. Its conductivity can be modified by adding impurities (" doping") to its crystal structure. When two regions with different doping levels are present in the same crystal, they form a semiconductor junction. The behavior of charge carriers, which include electrons, ions, and electron holes, at these junctions is the basis of diodes, transistors, and most modern electronics. Some examples of semiconductors are silicon, germanium, gallium arsenide, and elements near the so-called " metalloid staircase" on the periodic table. After silicon, gallium arsenide is the second-most common semiconductor and is used in laser diodes, solar cells, microwave-frequency integrated circuits, and others. Silicon is a critical element for fabricating most electronic circuits. Semiconductor devices can display a range of different useful properties, such as passing current more easil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
