Measurement of IWTO-19 ash content by Near Infrared Reflectance (NIR) Analysis
Wool Technology and Sheep Breeding 52:3 (2004) 245-259
Abstract:
The prediction of ash content of laboratory-scoured core samples utilising Near Infrared Reflectance Analysis (NIRA) has been investigated. Modified Partial Least Squares (MPLS) Regression was found to underestimate ash content when the sample being tested contained significant quantities of dag. The underestimation was not a consequence of saturation of the NIRA detector but rather appeared to be due to an inability of the MPLS technique to adequately account for dag which was present in the sample but masked by wool. Application of Artificial Neu ral Networks (ANN) Regression to the calibration data set produced improved results. The underestimation at higher ash levels was not as evident, indicating that ANN is better able to utilise the spectral information to predict total ash content. High levels of dag were found to adversely affect the repeatability of the IWTO-19 method for determining ash content. Uneven distribution of dag within samples was believed to be responsible. This finding has implications for NIRA, as any method of prediction can only be as good as the reference method to which it is calibrated.Recent results from SNO
Nuclear Physics B - Proceedings Supplements 137:1-3 SPEC. ISS. (2004) 15-20
Abstract:
The SNO project has now completed two of its three major phases of operation. The no-oscillation hypothesis has been ruled out at 5σ in the pure heavy water phase and 8σ in the salt phase. Discussion in terms of the SeeSaw model is presented. © 2004 Published by Elsevier B.V.Design Constraints for a WIMP Dark Matter and pp Solar Neutrino Liquid Neon Scintillation Detector
ArXiv nucl-ex/0410025 (2004)
Abstract:
Detailed Monte-Carlo simulations were used to evaluate the performance of a liquid neon scintillation detector for dark matter and low-energy solar neutrino interactions. A maximum-likelihood event vertex fitter including PMT time information was developed, which significantly improves position resolution over spatial-only algorithms, and substantially decreases the required detector size and achievable analysis energy threshold. The ultimate sensitivity to WIMP dark matter and the pp flux uncertainty are evaluated as a function of detector size. The dependence on the neon scintillation and PMT properties are evaluated. A 300 cm radius detector would allow a ~13 keV threshold, a pp flux uncertainty of ~1%, and limits on the spin-independent WIMP-nucleon cross-section of ~10^{-46} cm^2 for a 100 GeV WIMP, using commercially available PMTs. Detector response calibration and background requirements for a precision pp measurement are defined. Internal radioactivity requirements for uranium, thorium, and krypton are specified, and it is shown that the PMT data could be used for an in-situ calibration of the troublesome krypton-85. A set of measurements of neon scintillation properties and PMT characteristics are outlined which will be needed in order to evaluate feasibility and fully optimize the design of a neon-based detector.Comparison of Three-jet Events in Proton-Antiproton Collisions at Center-of-mass Energy 1.8 TeV to Predictions from a Next-to-leading Order QCD Calculation
ArXiv hep-ex/0410018 (2004)
Abstract:
The properties of three-jet events with total transverse energy greater than 320 GeV and individual jet energy greater than 20 GeV have been analyzed and compared to absolute predictions from a next-to-leading order (NLO) perturbative QCD calculation. These data, of integrated luminosity 86 pb^-1, were recorded by the CDF Experiment for proton-antiproton collisions at sqrt{s}=1.8 TeV. This study tests a model of higher order QCD processes that result in gluon emission and can be used to estimate the magnitude of the contribution of processes higher than NLO. The total cross section is measured to be 466 +/- 3(stat.)^{+207}_{-70}(syst.) pb. The differential cross section is furthermore measured for all kinematically accessible regions of the Dalitz plane, including those for which the theoretical prediction is unreliable. While the measured cross section is consistent with the theoretical prediction in magnitude, the two differ somewhat in shape in the Dalitz plane.Inclusive double-pomeron exchange at the fermilab tevatron p p collider.
Phys Rev Lett 93:14 (2004) 141601