Telescope Array Project: Difference between revisions

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Revision as of 18:57, 24 July 2014

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The '''Telescope Array project''' is an international collaboration involving research and educational institutions in Japan, The United States, Russia, South Korea, and Belgium.<ref name=Tokuno>{{cite journal|last=Tokuno|first=H.|coauthorsauthor2=et al |title=New air fluorescence detectors employed in the Telescope Array experiment|journal=Nuclear Instruments and Methods in Physics Research A|date=21 February 2012|volume=676|pages=54–65|doi=10.1016/j.nima.2012.02.044|arxiv = 1201.0002 |bibcode = 2012NIMPA.676...54T }}</ref> The experiment is designed to observe air showers induced by [[ultra-high-energy cosmic ray]] using a combination of ground array and air-fluorescence techniques. It is located in the high desert in [[Millard County, Utah|Millard County]], [[Utah]] (USA) at about {{convert|1400|m|ft|sp=us}} above sea level.

==Overview==

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==Surface detector==

[[Image:SurfaceDetection.svg|right|200px|A Scintillator Surface Detector from Telescope Array]]

The surface detectors that make up the ground array are activated when ionizing particles from an extensive air shower pass through them. When these particles pass through the plastic scintillator within the detector, it induces photo electrons which are then gathered by wavelength-shifting fibers and sent to a photomultiplier tube. The electronic components within the detectors then filter the results, giving the detectors comparable accuracy to the AGASA experiment.<ref name=Kawai2008>{{cite journal|last=Kawai|first=H|coauthorsauthor2=et al |title=Telescope Array Experiment|journal=Nuclear Physics B (Proceedings Supplements)|year=2008|pages=220–226|doi=10.1016/j.nuclphysbps.2007.11.002|bibcode = 2008NuPhS.175..221K }}</ref>

The surface detectors are evenly distributed across a 762&nbsp;km² grid array with 1.2&nbsp;km between each unit. Each surface detector has an assembled weight of 250&nbsp;kg and consists of a power supply, two layers of scintillation detectors and electronics. Power is generated by a 120W solar panel and stored in a sealed lead-acid battery. The system has the capacity to operate for one week in complete darkness. Each scintillation detector layer is made of extruded plastic scintillator that is 1.2&nbsp;cm thick and has an area of 3m². The photo multiplier tube is connected to the scintillator via 96 wavelength-shifting fibers.

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==TARA==

The Telescope Array RADAR (TARA) Project is an effort to overcome some of the problems inherent to current cosmic ray detection techniques. Due to sun, moon and weather, fluorescence telescopes are usually limited to a ten percent duty cycle. Ground arrays can run during the day, but require a large amount of land, making it necessary to build them in remote locations. The goal of the TARA Project is to develop a [[bistatic radar]] detection system that is able to maintain a 24 hour duty cycle at a fraction of the cost of conventional detection systems.<ref name=AbouBakrOthman2011>{{cite journal|last=Abou Bakr Othman|first=M.|coauthorsauthor2=et al |title=Radar Detection of UHECR Air Showers at the Telescope Array|journal=32nd International Cosmic Ray Conference, Beijing 2011|year=2011}}</ref>

In September 2012, the [[W. M. Keck Foundation]] awarded researchers at the University of Utah a $1 million grant to develop a bistatic radar detection system. This system will be built alongside the existing Telescope Array and will use analog television transmitters and digital receivers to observe the range, direction and strength of cosmic rays in order to trace them back to their point of origin.<ref name=EON2012>{{cite news|title=University of Utah Awarded $1 Million by Keck Foundation to Study Cosmic Rays|url=http://eon.businesswire.com/news/eon/20120925005365/en/University-Utah-Awarded-1-Million-Keck-Foundation|accessdate=2 July 2013|newspaper=EON: Enhanced Online News|date=September 25, 2012}}</ref> Once completed, this new facility will be known as the W.M. Keck Radar Observatory<ref name=EON2012 /><ref name=Lee2012>{{cite news|last=Lee|first=Jasen|title=$1M grant awarded to U. to study cosmic particles|url=http://www.ksl.com/?nid=148&sid=22296297|accessdate=2 July 2013|newspaper=KSL|date=September 25, 2012}}</ref>