Design of the quartermaster solar furnace

Davies, J. M.; Cotton, E.

doi:10.1016/0038-092x(57)90116-0

Cited by 167 publications

(111 citation statements)

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“…Using several small sensors in one channel has the advantage that the application of solid cones is possible in terms of weight and transmission and costs for photo sensors can be kept low due to their at least two times higher compression ratio. The Davies-Cotton design [15] is known to be promising for wide field prime-focus telescopes and was studied earlier analytically [16] and through simulations [17]. However, the parametrizations are moderately accurate and non existing for tessellated reflectors.…”

Section: Resultsmentioning

confidence: 99%

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Design constraints on Cherenkov telescopes with Davies–Cotton reflectors

Bretz

Ribordy

2013

Astroparticle Physics

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This paper discusses the construction of high-performance ground-based gamma-ray Cherenkov telescopes with a Davies-Cotton reflector. For the design of such telescopes, usually physics constrains the field-of-view, while the photo-sensor size is defined by limited options. Including the effect of light-concentrators in front of the photo sensor, it is demonstrated that these constraints are enough to mutually constrain all other design parameters. The dependability of the various design parameters naturally arises once a relationship between the value of the point-spread functions at the edge of the field-of-view and the pixel field-of-view is introduced. To be able to include this constraint into a system of equations, an analytical description for the point-spread function of a tessellated Davies-Cotton reflector is derived from Taylor developments and ray-tracing simulations. Including higher order terms renders the result precise on the percent level. Design curves are provided within the typical phase space of Cherenkov telescopes. The impact of all design parameters on the overall design is discussed. Allowing an immediate comparison of several options with identical physics performance allows the determination of the most cost efficient solution. Emphasize is given on the possible application of solid light concentrators with their typically about two times better concentration allowing the use of small photo sensors such as Geiger-mode avalanche photo diodes. This is discussed in more details in the context of possible design options for the Cherenkov Telescope Array. In particular, a solution for a 60 mm 2 photo sensor with hollow cone is compared to a 36 mm 2 with solid cone.

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Section: Resultsmentioning

confidence: 99%

“…Therefore, segmented mirrors are in use. The layout providing the best optical quality for segments of identical focal length is the so-called Davies-Cotton layout [15], where the single spherical mirrors are located on a sphere with radius F and focused to a point at 2F.…”

Section: Optical Qualitymentioning

confidence: 99%

Design constraints on Cherenkov telescopes with Davies–Cotton reflectors

Bretz

Ribordy

2013

Astroparticle Physics

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“…and VERITAS collaborations: a 12 m diameter Davies-Cotton [16] reflector with f/D = 1.3 and a PMT-based camera covering at least 7 • FoV. An alternative design based on the SchwarzschildCouder [17] dual-mirror optical layout and a SiPMbased camera is being developed.…”

Section: Medium Size Telescopesmentioning

confidence: 99%

The Cherenkov Telescope Array

Bigongiari

2016

Nuclear and Particle Physics Proceedings

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The Cherenkov Telescope Array (CTA) is planned to be the next generation ground based observatory for very high energy (VHE) gamma-ray astronomy. Gamma-rays provide a powerful insight into the non-thermal universe and hopefully a unique probe for new physics. Imaging Cherenkov telescopes have already discovered more than 170 VHE gamma-ray emitters providing plentiful of valuable data and clearly demonstrating the power of this technique. In spite of the impressive results there are indications that the known sources represent only the tip of the iceberg. A major step in sensitivity is needed to increase the number of detected sources, observe short time-scale variability and improve morphological studies of extended sources. An extended energy coverage is advisable to observe far-away extragalactic objects and improve spectral analysis. CTA aims to increase the sensitivity by an order of magnitude compared to current facilities, to extend the accessible gamma-ray energies from a few tens of GeV to a hundred of TeV, and to improve on other parameters like angular and energy resolution. CTA will provide moreover a full sky-coverage by featuring an array of imaging atmospheric Cherenkov telescopes in both hemispheres.This paper presents an overview of the technical design and summarize the current status of the project. CTA prospects for some key science topics like the origin of relativistic cosmic particles, the acceleration mechanisms in extreme environments such as neutron stars and black holes and searches for Dark Matter are discussed.

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“…Each telescope is of Davies-Cotton design (Davies & Cotton 1957) with a 12-m diameter reflector, and the array is arranged in a diamond configuration with ∼ 100 m to a side. Each reflector comprises 345 identical hexagonal mirror facets and has a collection area of 110 m 2 .…”

Section: Veritas Instrumentmentioning

confidence: 99%

VERITAS detection of gamma-ray flaring activity from the BL Lac object 1ES1727+502 during bright moonlight observations

Cerruti¹

2016

Proceedings of the 34th International Cosmic Ray Conference — PoS(ICRC2015)

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During moonlit nights, observations with ground-based Cherenkov telescopes at very high energies (VHE, E > 100 GeV) are constrained since the photomultiplier tubes (PMTs) in the telescope camera are extremely sensitive to the background moonlight. Observations with the VERITAS telescopes in the standard configuration are performed only with a moon illumination less than 35% of full moon. Since 2012, the VERITAS collaboration has implemented a new observing mode under bright moonlight, by either reducing the voltage applied to the PMTs (reduced-high-voltage configuration, RHV), or by utilizing UV-transparent filters. While these operating modes result in lower sensitivity and increased energy thresholds, the extension of the available observing time is useful for monitoring variable sources such as blazars and sources requiring spectral measurements at the highest energies. In this paper we report the detection of γ-ray flaring activity from the BL Lac object 1ES 1727+502 during RHV observations. This detection represents the first evidence of VHE variability from this blazar. The integral flux is (1.1 ± 0.2) × 10 −11 cm −2 s −1 above 250 GeV, which is about five times higher than the low-flux state. The detection triggered additional VERITAS observations during standard dark-time. Multiwavelength observations with the FLWO 48" telescope, and the Swift and Fermi satellites are presented and used to produce the first spectral energy distribution (SED) of this object during γ-ray flaring activity. The SED is then fitted with a standard synchrotron-self-Compton model, placing constraints on the properties of the emitting region and of the acceleration mechanism at the origin of the relativistic particle population in the jet.

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Design of the quartermaster solar furnace

Cited by 167 publications

References 1 publication

Design constraints on Cherenkov telescopes with Davies–Cotton reflectors

Design constraints on Cherenkov telescopes with Davies–Cotton reflectors

The Cherenkov Telescope Array

VERITAS detection of gamma-ray flaring activity from the BL Lac object 1ES1727+502 during bright moonlight observations

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