978 research outputs found
Everything Under the Sun: A Review of Solar Neutrinos
Solar neutrinos offer a unique opportunity to study the interaction of
neutrinos with matter, a sensitive search for potential new physics effects,
and a probe of solar structure and solar system formation. This paper describes
the broad physics program addressed by solar neutrino studies, presents the
current suite of experiments programs, and describes several potential future
detectors that could address the open questions in this field. This paper is a
summary of a talk presented at the Neutrino 2014 conference in Boston
Time Response of Water-based Liquid Scintillator from X-ray Excitation
Water-based liquid scintillators (WbLS) present an attractive target medium
for large-scale detectors with the ability to enhance the separation of
Cherenkov and scintillation signals from a single target. This work
characterizes the scintillation properties of WbLS samples based on LAB/PPO
liquid scintillator (LS). X-ray luminescence spectra, decay profiles, and
relative light yields are measured for WbLS of varying LS concentration as well
as for pure LS with a range of PPO concentrations up to 90 g/L. The
scintillation properties of the WbLS are related to the precursor LAB/PPO:
starting from 90 g/L PPO in LAB before synthesis, the resulting WbLS have
spectroscopic properties that instead match 10 g/L PPO in LAB. This could
indicate that the concentration of active PPO in the WbLS samples depends on
their processing.Comment: 6 pages, 7 figures, 2 tables. Submitted to Materials Advances, a
journal of the Royal Society of Chemistr
Cherenkov and Scintillation Light Separation in Organic Liquid Scintillators
The CHErenkov / Scintillation Separation experiment (CHESS) has been used to
demonstrate the separation of Cherenkov and scintillation light in both linear
alkylbenzene (LAB) and LAB with 2g/L of PPO as a fluor (LAB/PPO). This is the
first such demonstration for the more challenging LAB/PPO cocktail and improves
on previous results for LAB. A time resolution of 338 +/- 12 ps FWHM results in
an efficiency for identifying Cherenkov photons in LAB/PPO of 70 +/- 3% and 63
+/- 8% for time- and charge-based separation, respectively, with scintillation
contamination of 36 +/- 5% and 38 +/- 4%. LAB/PPO data is consistent with a
rise time of 0.75 +/- 0.25 ns
Valuing portfolios of interdependent real options using influence diagrams and simulation-and-regression: A multi-stage stochastic integer programming approach
Although real options generally occur within portfolios, most valuation approaches based on either option pricing or decision analysis alone focus on single well-defined options. In this paper we present a new approach for modelling and approximating the value of portfolios of interdependent real options using both influence diagrams and simulation-and-regression. The key feature of this approach is that it translates the interdependencies between real options into a set of constraints and then directly models the dynamics of all underlying uncertainties using (Markovian) stochastic processes. These are then integrated in a portfolio optimisation problem which is formulated as a multi-stage stochastic integer program. Applying a simulation and parametric regression approach to approximate the value of this optimisation problem, we present a transparent valuation algorithm that explicitly takes into account vector-valued exercise decisions and the state variable’s multidimensional resource component. The approach is therefore applicable to a wide range of complex investment projects with both inherent interdependent flexibilities and many underlying uncertainties. The approach is illustrated by evaluating a complex natural resource investment that features both a large portfolio of interdependent real options and four stochastic factors. We analyse the way in which the approximated value of the portfolio and its individual options are affected by the initial copper price as well as by the degrees of production cost and copper price uncertainty
Advanced modulation technology development for earth station demodulator applications
The purpose of this contract was to develop a high rate (200 Mbps), bandwidth efficient, modulation format using low cost hardware, in 1990's technology. The modulation format chosen is 16-ary continuous phase frequency shift keying (CPFSK). The implementation of the modulation format uses a unique combination of a limiter/discriminator followed by an accumulator to determine transmitted phase. An important feature of the modulation scheme is the way coding is applied to efficiently gain back the performance lost by the close spacing of the phase points
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