Distributed Computing Grid Experiences in CMS

The CMS experiment is currently developing a computing system capable of serving, processing and archiving the large number of events that will be generated when the CMS detector starts taking data. During 2004 CMS undertook a large scale data challenge to demonstrate the ability of the CMS computing system to cope with a sustained data-taking rate equivalent to 25% of startup rate. Its goals were: to run CMS event reconstruction at CERN for a sustained period at 25 Hz input rate; to distribute the data to several regional centers; and enable data access at those centers for analysis. Grid middleware was utilized to help complete all aspects of the challenge. To continue to provide scalable access from anywhere in the world to the data, CMS is developing a layer of software that uses Grid tools to gain access to data and resources, and that aims to provide physicists with a user friendly interface for submitting their analysis jobs. This paper describes the data challenge experience with Grid infrastructure and the current development of the CMS analysis system

Computational Methodology for Optimal Design of Additive Layer Manufactured Turbine Bracket

The design of critical components for aircrafts, cars or any other kind of machinery today is typically subject to two conflicting objectives, namely the maximisation of strength and the minimisation of weight. The conflicting nature of these two objectives makes it impossible to obtain a design that is optimal for both. The most common approach aiming for a single objective optimisation problem in aerospace is to maintain the weight minimisation as the objective, whilst setting strength requirements as constraints to be satisfied. However, manufacturing methods incorporate additional restrictions for an optimal design to be considered feasible, even when satisfying all constraints in the formulation of the optimisation problem. In this context, Additive Layer Manufacturing adds remarkably higher flexibility to the manufacturability of shape designs when compared with traditional processes. It is fair to note, however, that there are still some restrictions such as the infeasibility of building unsupported layers forming angles smaller than 45 degrees with respect to the underlying one. Nowadays, it is common practice to use a set of software tools to deal with these kinds of problems, namely Computer Aided Design (CAD), Finite Element Analysis (FEA), and optimisation packages. The adequate use of these tools results in an increase in efficiency and quality of the final product. In this paper, a case study was undertaken consisting of a turbine bracket from a General Electric challenge. A computational methodology is used, which consists of a topology optimisation considering an isotropic material at first instance, followed by the manual refinement of the resulting shape taking into account the manufacturability requirements. To this end, we used SolidWorks®2013 for the CAD, Ansys Workbench®14.0 for the FEA, and HyperWorks®11 for the topology optimisation. A future methodology will incorporate the automation of the shape optimisation stage, and perhaps the inclusion of the manufacturability restriction within the optimisation formulation

Core integrated simulations for the Divertor Tokamak Test facility scenarios towards consistent core-pedestal-SOL modelling

Deuterium plasma discharges of the Divertor Tokamak Test facility (DTT) in different operational scenarios have been predicted by a comprehensive first-principle based integrated modelling activity using state-of-art quasi-linear transport models. The results of this work refer to the updated DTT configuration, which includes a device size optimisation (enlargement to R-0=2.19 a = 0.70 m) and upgrades in the heating systems. The focus of this paper is on the core modelling, but special attention was paid to the consistency with the scrape-off layer parameters required to achieve divertor plasma detachment. The compatibility of these physics-based predicted scenarios with the electromagnetic coil system capabilities was then verified. In addition, first estimates of DTT sawteeth and of DTT edge localised modes were achieved

First-principle based multi-channel integrated modelling in support to the design of the Divertor Tokamak Test facility

An intensive integrated modelling work of main scenarios of the new tokamak DTT (Divertor Tokamak Test facility) with the Single Null divertor configuration has been performed using first-principle quasi-linear transport models, in support to the design of the device and to the definition of its scientific work-programme. First results of this integrated modelling work on DTT (R0= 2.14 m, a= 0.65 m) are presented here along with outcome of the gyrokinetic simulations used to validate the reduced models in the DTT range of parameters. As a result of this work, the heating mix was defined, the size of device was increased to R0= 2.19 m and a= 0.70 m, the use of pellets for fuelling has been advised and reference profiles for diagnostic design, estimates of neutron yields and fast particle losses have become available.</p

Search for Charginos with a Small Mass Difference with the Lightest Supersymmetric Particle at \sqrt{s} = 189 GeV

A search for charginos nearly mass-degenerate with the lightest supersymmetric particle is performed using the 176 pb^-1 of data collected at 189 GeV in 1998 with the L3 detector. Mass differences between the chargino and the lightest supersymmetric particle below 4 GeV are considered. The presence of a high transverse momentum photon is required to single out the signal from the photon-photon interaction background. No evidence for charginos is found and upper limits on the cross section for chargino pair production are set. For the first time, in the case of heavy scalar leptons, chargino mass limits are obtained for any \tilde{\chi}^{+-}_1 - \tilde{\chi}^0_1 mass difference

Precise measurement of the W-boson mass with the CDF II detector

We have measured the W-boson mass MW using data corresponding to 2.2/fb of integrated luminosity collected in proton-antiproton collisions at 1.96 TeV with the CDF II detector at the Fermilab Tevatron collider. Samples consisting of 470126 W->enu candidates and 624708 W->munu candidates yield the measurement MW = 80387 +- 12 (stat) +- 15 (syst) = 80387 +- 19 MeV. This is the most precise measurement of the W-boson mass to date and significantly exceeds the precision of all previous measurements combined