Telescope Array Project: Difference between revisions

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{{short description|Research project to observe air showers}}

[[Image:Taplogo.png|right|200px|Telescope Array Project logo]]

{{Use American English|date=July 2025}}

The '''Telescope Array project''' is an international collaboration involving research and educational institutions in Japan, Taiwan, China, Russia, South Korea, and the United States. The experiment is designed to observe [[ultra-high-energy cosmic ray]] air showers 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.

{{Infobox telescope|___location=[[Millard County, Utah]], US}}

The '''Telescope Array project''' is an international collaboration involving research and educational institutions in Japan, Taiwan,The ChinaUnited States, Russia, South Korea, and Belgium.<ref name=Tokuno>{{cite journal|last=Tokuno|first=H.|display-authors=etal |title=New air fluorescence detectors employed in the UnitedTelescope StatesArray 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 |s2cid=9896454}}</ref> The experiment is designed to observe air showers induced by [[ultra-high-energy cosmic ray]] air showers 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)United States, at about {{convert|1400|m|ft|sp=us}} above sea level.

==Overview==

[[File:TelescopeArray.svg|thumb|left|An illustration of Telescope Array. Three fluorescence telescopes observe the ultraviolet light given off by an air shower, while an array of surface detectors register the particles as they strike the ground.]]

The TATelescope Array observatory is a hybrid detector system consisting of both an array of 507 scintillation surface detectors (SD) which measure the distribution of charged particles at the Earth's surface, and three fluorescence stations which observe the night sky above the SD array.<ref name="AbuZayyad2012">T. AbuZayyad et al., "[http://www.telescopearray.org/media/TA_papers/1-s2.0-S0168900212005931-main.pdf The surface detector array of the Telescope Array experiment]" Nuclear Instruments and Methods in Physics Research Section A: (2012) vol. 689</ref> Each fluorescence station is also accompanied by a LIDAR system for atmospheric monitoring.<ref name="chikawaICRC">M. Chikawa et al., Proceedings of 29th [[International Cosmic Ray Conference|ICRC]] (2005) 137</ref> The SD array is much like that of the [[AGASA]] group, but covers an area that is nine times larger. The hybrid setup of the Telescope Array project allows for simultaneous observation of both the longitudinal development and the lateral distribution of the air showers. When a cosmic ray passes through the Earth's atmosphere and triggers an [[Air shower (physics)|air shower]], the fluorescence telescopes measure the scintillation light generated as the shower passes through the gas of the atmosphere, while the array of scintillator surface detectors samples the footprint of the shower when it reaches the Earth's surface.

At the center of the ground array is the Central Laser Facility which is used for atmospheric monitoring and calibrations.

==CosmicSurface Ray Centerdetector==

[[File:SurfaceDetection.svg|thumb|A Scintillator Surface Detector from Telescope Array]]

The Lon and Mary Watson Millard County Cosmic Ray Center was dedicated on March 20, 2006.<ref>Draper, Dean (March 22, 2006). "Cosmic ray center dedicated". Millard County Chronicle Progress</ref> The center is located in Delta - the seat of Millard County. The building serves as a headquarters and data processing center for the TA Project.

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 scintillation photons to be emitted which are then gathered by 96 wavelength-shifting fibers and sent to photomultiplier tubes. 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|display-authors=etal |title=Telescope Array Experiment|journal=Nuclear Physics B: Proceedings Supplements|volume=175-176|date=2008|pages=220–226|doi=10.1016/j.nuclphysbps.2007.11.002|bibcode = 2008NuPhS.175..221K |s2cid=53604164}}</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.

==Surface detector==

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.

==FD station, telescope, and camera==

[[Image:BRM-FD-open.jpg|thumb|200px|right|a view of the Black Rock Mesa FD site with the doors open]]

{{GeoGroup}}

The Telescope Array has three fluorescence detector (FD) telescope stations. As in the previous Fly's Eye and [[High Resolution Fly's Eye Cosmic Ray Detector|High Resolution Fly's Eye]] (HiRes) experiments, these detectors work by measuring the air fluorescence light emitted by an [[Air shower (physics)|extensive air shower]]. Each FD telescope consists of a primary mirror (made up of 18&nbsp;smaller hexagonal mirror segments) and a camera. The cameras are made up of 256&nbsp;[[photomultiplier tube]]s (PMTs) which are sensitive to the [[ultraviolet]] light generated by a cosmic ray air shower.<ref name=Tokuno/>

The Telescope Array has three fluorescence detector stations. The stations are located on a triangle about 35&nbsp;km apart from one another. Each station has 12-14 telescopes viewing the range from 3 to 33 degrees in elevation. The three sites are named ''Black Rock Mesa'' (BRM), ''Long Ridge'' (LR), and ''Middle Drum'' (MD).<ref>http://www.telescopearray.org/index.php/research/clear-sky-clocks</ref>

The Telescope Array has three fluorescence detector stations. The stations are locatedpositioned on a triangle about 35&nbsp;km apart from one another with the Central Laser Facility close to the triangle's center. Each stationof hasthe 12-14three stations has 12–14&nbsp;telescopes viewing the range from 3°–33°&nbsp;[[elevation to 33 degrees in angle|elevation]]. The three sites are named ''Black Rock Mesa'' (BRM), ''Long Ridge'' (LR), and ''Middle Drum'' (MD).<ref>http://www.telescopearray.org/index.php/research/clear-sky-clocks</ref>

Each telescope has a fluorescence light camera made up of 256 PMTs.

{{cite web

|title=Clear sky clocks

*[ |url=http://www.telescopearray.org/ Telescope Array Project]index.php/research/clear-sky-clocks

}}

</ref>

By combining the data from the three sites, it is possible to determine the primary energy, the arrival direction, and the maximum point of longitudinal development for an air shower.<ref name=Tokuno/>

:{| class="wikitable"

|+Stations

|-

| Black Rock Mesa
|| {{Coord|39|11|18|N|112|42|42|W|format=dms|display=inline|name=Black Rock Mesa|type:landmark_region:US-UT}}
|| <ref name="Blackrock">
{{cite web

|author =Danko, A. Danko

|url =http://cleardarksky.com/c/TcpAr4UTkey.html?1

|title =Telescope Array Black Rock Mesa FD

|author =A. Danko

|publisher =Telescope Array Project

|url =http://cleardarksky.com/c/TcpAr4UTkey.html?1

|accessdate access-date=2012-12-25

}}</ref>

|-

| Long Ridge

|Long Ridge||{{Coord|39|12|28|N|113|07|17|W|format=dms|display=inline|name=Long Ridge|type:landmark_region:US-UT}}||<ref name="Longridge">{{cite web

|url =http://cleardarksky.com/c/TcpAr3UTkey.html?1

| <ref name="Longridge">

|title =Telescope Array Long Ridge FD

{{cite web

|author =Danko, A. Danko

|title =Telescope Array Long Ridge FD

|publisher =Telescope Array Project

|url =http://cleardarksky.com/c/TcpAr3UTkey.html?1

|author =A. Danko

|accessdate access-date=2012-12-25

}}</ref>

|-

| Middle Drum

|Middle Drum||{{Coord|39|28|22|N|112|59|37|W|format=dms|display=inline|name=Middle Drum|type:landmark_region:US-UT}}||<ref name="Middledrum">{{cite web

|url =http://cleardarksky.com/c/TcpAr2UTkey.html?1

| <ref name="Middledrum">

|title =Telescope Array Middle Drum FD

{{cite web

|author =Danko, A. Danko

|title =Telescope Array Middle Drum FD

|publisher =Telescope Array Project

|url =http://cleardarksky.com/c/TcpAr2UTkey.html?1

|author =A. Danko

|accessdate access-date=2012-12-25

}}</ref>

|-

| Central Laser Facility
|| {{Coord|39|17|49|N|112|54|31|W|format=dms|display=inline|name=Central Laser Facility|type:landmark_region:US-UT}}
|| <ref name="Centrallaser">
{{cite web

|author =Danko, A. Danko

|url =http://cleardarksky.com/c/TcpAryObUTkey.html?1

|title =Telescope Array Central Laser Facility

|publisher =Telescope Array Project

|url =http://cleardarksky.com/c/TcpAryObUTkey.html?1

|author =A. Danko

|accessdate access-date=2012-12-25

}}</ref>

|}

==Cosmic Ray Center==

The Lon and Mary Watson Millard County Cosmic Ray Center was dedicated on March 20, 2006.<ref>Draper, Dean (March 22, 2006). "Cosmic ray center dedicated". Millard County Chronicle Progress</ref> The center is located inat Delta648 -West theMain seatStreet ofin Millard CountyDelta. The building serves as a headquarters and data processing center for the TATelescope Array Project.

In October 2011, a new visitor center was opened at the Cosmic Ray Center. It features displays about the history of cosmic ray research in Utah and about the Telescope Array, which is spread across the desert west of Delta. The center also includes a display about the nearby [[Topaz War Relocation Center|Topaz internment camp]], where U.S. citizens of Japanese descent were imprisoned during World War II.

==TALE==

TALE is the Telescope Array Low Energy extension. It is designed to observe cosmic rays with energies between 3×10¹⁶eV and 10¹⁹eV. TALE hasadds two10 fluorescencenew sites,telescopes oneto ofthe whichMiddle isDrum locatedobservatory aboutsite 5&nbsp;km(24 awaytotal telescopes) extending the vertical field of view so that it extends from 3 to 59 degrees in elevation. This allows the Blackstation Rockto Mesasee FDthe site,shower anddevelopment including shower maximum for lower energy events. another whichThis is aboutcritical 5&nbsp;kmwhen awaytrying fromto determine the Longchemical Ridgecomposition FDof sitethe incident cosmic ray particle.<ref name="tawebsite"Martens2007>www{{cite journal|last=Martens|first=Kai|title=The Telescope Array and its Low Energy Extension|journal=Nuclear Physics B: Proceedings Supplements|date=2007|volume=165|pages=33–36|doi=10.telescopearray.org1016/researchj.htmlnuclphysbps.2006.11.006|bibcode = 2007NuPhS.165...33M }}</ref>

The TALE project also has ana graded infill array of scintillator groundstations spaced 400m and 600m apart. It then connects to the main Telescope Array scintillator array stationswhere spacedthe aboutscintillator 500mdetectors are 1200m apart. These stations measure charged particle densities (the shower footprint) at the Earth's surface for lower energy events approaching 3x10¹⁶eV

The TALE tower is a tower of fluorescence telescopes looking from near zenith to near horizon. These telescopes have 3m diameter mirrors to push the energy threshold of observable events as low as possible.

==TARA==

The TALE project also has an infill array of scintillator ground array stations spaced about 500m apart. These stations measure charged particle densities (the shower footprint) at the Earth's surface for lower energy events approaching 3x10¹⁶eV

The Telescope Array RADAR (TARA) Project is an effort to overcome some of the problems inherent to existing 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.|display-authors=etal |title=Radar Detection of UHECR Air Showers at the Telescope Array|journal=32nd International Cosmic Ray Conference, Beijing 2011|date=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}}{{Dead link|date=August 2025 |bot=InternetArchiveBot |fix-attempted=yes }}</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>

==See also==

* [[Amaterasu particle]]

==References==

{{reflist|225em}}

{{University of Utah}}

==External links==

*[http://www.telescopearray.org/ Telescope Array Project]

[[Category:High energy particle telescopes]]

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[[Category:Stellar phenomena]]

[[Category:Astronomical observatories in Utah]]

[[Category:University of Utah]]

[[Category:Buildings and structures in Millard County, Utah]]

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