| 1. |
- Acharya, B. S., et al.
(författare)
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Introducing the CTA concept
- 2013
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Ingår i: Astroparticle physics. - : Elsevier BV. - 0927-6505 .- 1873-2852. ; 43, s. 3-18
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project. (C) 2013 Elsevier B.V. All rights reserved.
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| 2. |
- Actis, M., et al.
(författare)
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Design concepts for the Cherenkov Telescope Array CTA : an advanced facility for ground-based high-energy gamma-ray astronomy
- 2011
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Ingår i: Experimental astronomy. - : Springer. - 0922-6435 .- 1572-9508. ; 32:3, s. 193-316
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Tidskriftsartikel (refereegranskat)abstract
- Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.
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| 3. |
- Acero, F., et al.
(författare)
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Prospects for Cherenkov Telescope Array Observations of the Young Supernova Remnant RX J1713.7-3946
- 2017
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Ingår i: Astrophysical Journal. - : Institute of Physics Publishing (IOPP). - 0004-637X .- 1538-4357. ; 840:2
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Tidskriftsartikel (refereegranskat)abstract
- We perform simulations for future Cherenkov Telescope Array (CTA) observations of RX J1713.7-3946, a young supernova remnant (SNR) and one of the brightest sources ever discovered in very high energy (VHE) gamma rays. Special attention is paid to exploring possible spatial (anti) correlations of gamma rays with emission at other wavelengths, in particular X-rays and CO/H I emission. We present a series of simulated images of RX J1713.7-3946 for CTA based on a set of observationally motivated models for the gamma-ray emission. In these models, VHE gamma rays produced by high-energy electrons are assumed to trace the nonthermal X-ray emission observed by XMM-Newton, whereas those originating from relativistic protons delineate the local gas distributions. The local atomic and molecular gas distributions are deduced by the NANTEN team from CO and H I observations. Our primary goal is to show how one can distinguish the emission mechanism(s) of the gamma rays (i.e., hadronic versus leptonic, or a mixture of the two) through information provided by their spatial distribution, spectra, and time variation. This work is the first attempt to quantitatively evaluate the capabilities of CTA to achieve various proposed scientific goals by observing this important cosmic particle accelerator.
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| 4. |
- Miyake, F., et al.
(författare)
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A Single-Year Cosmic Ray Event at 5410 BCE Registered in 14C of Tree Rings
- 2021
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Ingår i: Geophysical Research Letters. - 0094-8276. ; 48:11
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Tidskriftsartikel (refereegranskat)abstract
- The annual 14C data in tree rings is an outstanding proxy for uncovering extreme solar energetic particle (SEP) events in the past. Signatures of extreme SEP events have been reported in 774/775 CE, 992/993 CE, and ∼660 BCE. Here, we report another rapid increase of 14C concentration in tree rings from California, Switzerland, and Finland around 5410 BCE. These 14C data series show a significant increase of ∼6‰ in 5411–5410 BCE. The signature of 14C variation is very similar to the confirmed three SEP events and points to an extreme short-term flux of cosmic ray radiation into the atmosphere. The rapid 14C increase in 5411/5410 BCE rings occurred during a period of high solar activity and 60 years after a grand 14C excursion during 5481–5471 BCE. The similarity of our 14C data to previous events suggests that the origin of the 5410 BCE event is an extreme SEP event.
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| 5. |
- Periale, L., et al.
(författare)
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Successful operation of hole-type gaseous detectors at cryogenic temperatures
- 2004
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Ingår i: 2004 IEEE Nuclear Science Symposium Conference Record. - 0780387007 ; , s. 1147-1151
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Konferensbidrag (refereegranskat)abstract
- We have demonstrated that hole-type gaseous detectors, GEMs and capillary plates, can operate up to 77 K. For example, a single capillary plate can operate at gains of above 103 in the entire temperature interval between 300 until 77 K. The same capillary plate combined with Csi photocathodes could operate perfectly well at gains (depending on gas mixtures) of 100-1000. Obtained results may open new fields of applications for capillary plates as detectors of UV light and charge particles at cryogenic temperatures: noble liquid TPCs, WIMP detectors or LXe scintillating calorimeters and cryogenic PETs.
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| 6. |
- Periale, L., et al.
(författare)
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The successful operation of hole-type gaseous detectors at cryogenic temperatures
- 2005
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Ingår i: IEEE Transactions on Nuclear Science. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9499 .- 1558-1578. ; 52:4, s. 927-931
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Tidskriftsartikel (refereegranskat)abstract
- We have demonstrated that hole-type gaseous detectors, gas electron multipliers and capillary plates (CPs) can operate at temperatures down to 77 K. For example, a single CP can operate at gains above 10(3) in the entire temperature interval between 77 and 300 K. The same CP combined with CsI photocathodes operates perfectly well at gains of 100-1000, depending on the gas mixture. The obtained results open new fields of applications for CPs as detectors of ultraviolet light and charged particles at cryogenic temperatures: liquid noble gas time-projection chambers, detectors for weakly interacting massive particles or liquid Xe scintillating calorimeters, and cryogenic positron-emission tomography.
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| 7. |
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| 8. |
- Iacobaeus, C., et al.
(författare)
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A high position resolution X-ray detector : An Edge on illuminated capillary plate combined with a gas amplification structure
- 2006
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Ingår i: IEEE Transactions on Nuclear Science. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9499 .- 1558-1578. ; 53:2, s. 554-561
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Tidskriftsartikel (refereegranskat)abstract
- We have developed and successfully tested a prototype of a new high position resolution hybrid X-ray detector. It contains a thin-wall lead glass capillary plate converter of X-rays combined with a microgap parallel-plate avalanche chamber operating in various gas mixtures at 1 atm. The operation of these converters was studied in a wide range of X-ray energies (from 6 to 60 keV) at incident angles varying from 0-90 degrees. The detection efficiency, depending on the geometry, photon's energy, incident angle and the mode of operation was between 5-30% in single step mode and up to 50% in a multi-layered combination. Depending on the capillary's geometry, the position resolution achieved was between 50-250 mu m in digital form and was practically independent of the photon's energy or gas mixture. The usual lead glass capillary plates operated without noticeable charging up effects at counting rates of 50 Hz/mm(2) and hydrogen treated capillaries-up to 10(5) Hz/mm(2). The developed detector has several important potential advantages over the exciting X-ray detectors and may open new possibilities for medical imaging, for example in mammography, portal imaging, radiography (including security devices), as well as many other applications.
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| 9. |
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| 10. |
- Iacobaeus, C., et al.
(författare)
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An X-ray scanner based on an "edge on" illuminated capillary plate combined with a gas amplification structure
- 2004
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Ingår i: 2004 IEEE Nuclear Science Symposium Conference Record. ; , s. 489-492
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Konferensbidrag (refereegranskat)abstract
- We have developed and successfully tested a prototype of a new type of high position resolution X-ray scanner. It contains a thin wall lead glass capillary plate converter of X-rays combined with a microgap parallel-plate avalanche chamber operating in various gas mixtures at 1 atm. The operation of these converters was studied in a wide range of X-ray energies (from 6 to 60 keV) at incident angles varying from 0-90°. The detection efficiency, depending on the geometry, photon's energy, incident angle and the mode of operation, was between 5-30% in a single step mode and up to 50% in a multi-layered combination. Depending on the capillary's geometry, the position resolution achieved was between 50-250 μm in digital form and was practically independent of the photon's energy or gas mixture. The usual lead glass capillary plates operated without noticeable charging up effects at counting rates of 50 Hz/mm2, and hydrogen treated capillaries up to 10 5 Hz/mm2. Finally, a prototype of the X-ray scanner based on an "edge-on" illumination capillary plate was built and tested. The developed detector open new possibilities for medical imaging, for example in mammography, portal imaging, radiography (including security devices), crystallography and many other applications.
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