The Design of Liquid Scintillation Cells
01 Dec 1952-Review of Scientific Instruments (American Institute of Physics)-Vol. 23, Iss: 12, pp 755-757
About: This article is published in Review of Scientific Instruments.The article was published on 1952-12-01. It has received 48 citations till now. The article focuses on the topics: Scintillation & Liquid scintillation counting.
Citations
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TL;DR: A discussion of the limits imposed by thermodynamics on the collection of light from scintillation counters by photocathodes is given, and a method for concentrating the light energy to any degree is pointed out as mentioned in this paper.
Abstract: A discussion of the limits imposed by thermodynamics on the collection of light from scintillation counters by photocathodes is given, and a method for concentrating the light energy to any degree is pointed out. The method employs a fluorescent material to slightly reduce the photon energy and thus to emit fluorescence. A light pipe-fluorescent converter-light pipe arrangement for increasing light intensity is discussed. (D.L.C.)
77 citations
Patent•
27 Jul 2006TL;DR: In this paper, a mixer comprising a light pipe having input and output ends and a central region there between is described, where light from the input end propagating along the optical path reflects from the sloping surfaces and is redirected at a different azimuthal direction toward the output end.
Abstract: Various embodiments described herein comprise mixers comprising a light pipe having input and output ends and a central region therebetween. An optical path extends in a longitudinal direction from the input end through the central region to the output end. The central region of the light pipe comprises one or more rippled reflective sidewalls having a plurality of elongate ridges and valleys and sloping surfaces therebetween. Light from the input end propagating along the optical path reflects from the sloping surfaces and is redirected at a different azimuthal direction toward the output end thereby mixing the light at the output end. Illuminance and/or color mixing can therefore be provided.
75 citations
TL;DR: In this paper, the influence of optical contact media, reflectors and light attenuation on the light collection performance of scintillators by systems using light conversion in fluorescent materials is discussed.
73 citations
15 Sep 1990-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, the average resolution of these detectors is determined to be σ/E ≈ 6.3%/√E (GeV) using a 300-element array of such modules.
Abstract: Electromagnetic calorimeter modules based on a uniform array of plastic scintillating fibers embedded in a lead alloy have been built and tested. Techniques have been developed to assemble large volumes of this composite material and to machine it into the tapered trapezoidal modules appropriate for modern, hermetically-sealed calorimeters with pointing geometry. Using this technique, a 300-element array of such modules has been built and instrumented. Prototypes and subsets of the larger array have been tested in electron and photon beams ranging in energy from 0.035 to 5.0 GeV. Improvements in fiber characteristics, assembly procedures, and geometrical optimization have led to substantial performance gains over previous similar detectors. The average resolution of these detectors is determined to be σ/E ≈ 6.3%/√E (GeV). The techniques of fabrication and the detector tests are described.
47 citations
TL;DR: In this article, the invariance of the Lagrange-Helmholtz invariant of the mirror profile is discussed, which is related to Liouville's theorem of Hamiltonian mechanics and there is a unifying method of constructing the mirror profiles by means of string.
Abstract: If light comes from a fixed direction and is to be collected onto an absorbing body which is approximately a point or a straight line, it is well known that a mirror of parabolic profile serves the purpose efficiently. If the light is diffuse, or its direction of incidence variable, or if the absorber is not approximately a point or a straight line, the parabola is less useful. This paper describes various particular collecting problems of this more general sort, together with efficient solutions for them, mainly by means of mirrors. The subject represents a corner of geometric optics little explored until recently, in which the notion of image formation scarcely appears. A unifying principle is the invariance of the ‘Lagrange-Helmholtz’ invariant, which is related to Liouville's theorem of Hamiltonian mechanics, and there is a unifying method of construction of the mirror profiles by means of string.
33 citations
References
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TL;DR: In this article, it was shown that the energy migrates from the original solvent to the second solvent and then to the fluorescent molecule, which can change the light emission curve completely.
Abstract: In organic solutions containing fluorescent molecules a considerable part of the high energy radiation absorbed in the bulk material is transformed into light emitted by the fluorescent molecules. There is a transfer of excitation energy from the bulk material to these molecules which reaches its maximum at concentrations of approximately 1 g/l and higher. Experiments with mixed solvents are described where relatively small concentrations (several mole percent) especially of naphthalene and $o$-diphenylbenzene act in some way as a second solvent. The excitation energy can be localized by investigating the fluorescence of these mixed solvents when different fluorescent solutes are added. It is found that the energy migrates from the original solvent to the second solvent and then to the fluorescent molecule. This intermediate energy transfer can change the light emission curve completely. From this change the dependence of the light emission on internal and self-quenching could be determined. Besides this internal energy transfer, an energy transfer via radiation occurs which is described in detail by studying the absorption of the fluorescent light inside the solution by adding small amounts of a second solute of the order of 0.1 g/l. Such small amounts change the light intensity considerably and shift the spectrum to the spectrum of the second solute. Photographs and data of the spectral distribution of such solutions are presented, which show that such drifts already occur with very small amounts of the second solute.
128 citations