review the design and construction of the detector and of its related infrastructures, and report on some technical performances of the various components. The construction of the detector started in 2003 and it was completed in Summer 2008. The experiment is presently in the data taking phase. The whole sequence of operations has proven to be successful, from triggering to brick selection, development, scanning and event analysis.
The electron-positron collider DAÈNE, the Italian È factory, has been recently upgraded in order to implement an innovative collision scheme based on large crossing angle, small beam sizes at the crossing point, and compensation of beam-beam interaction by means of sextupole pairs creating a ''crab-waist'' configuration in the interaction region. Experimental tests of the novel scheme exhibited an increase by a factor of 3 in the peak luminosity of the collider with respect to the performances reached before the upgrade. In this Letter we present the new collision scheme, discuss its advantages, describe the hardware modifications realized for the upgrade, and report the results of the experimental tests carried out during commissioning of the machine in the new configuration and standard operation for the users. DOI: 10.1103/PhysRevLett.104.174801 PACS numbers: 29.27.Bd, 29.20.db, 29.27.Eg Pushing the luminosity of storage-ring colliders to unprecedented levels opens up unique opportunities for precision measurements of rare decay modes and extremely small cross sections, which are sensitive to new physics beyond the standard model.In high luminosity colliders with conventional collision schemes the key requirements to increase the luminosity are: very small vertical beta function y at the interaction point (IP), high beam intensity and large horizontal emittance " x and beam size x . However, y cannot be much smaller than the longitudinal rms bunch size (bunch length) z without incurring the ''hour-glass'' effect. Unfortunately, it is very difficult to shorten the bunch in a high current ring without exciting collective instabilities. Even then, the large beam current may result in high power losses, beam instabilities and dramatic increase of the wallplug power. These problems can be overcome with the recently proposed crab-waist (CW) scheme of beambeam collisions [1,2] where a substantial luminosity increase can be achieved without bunch length reduction and with moderate beam currents.The CW scheme has been successfully tested at the electron-positron collider DAÈNE, the Italian È factory [3,4] operating at the energy of 1020 MeV in the center of mass. After an upgrade including the implementation of this novel collision scheme, the specific luminosity at low beam currents has been boosted by more than a factor of 4, while the present peak luminosity is a factor of 3 higher than the maximum value obtained with the original configuration based on the standard collision scheme.The successful test has provided the opportunity to continue the DAÈNE physics program. Moreover, the advantages of the crab-waist collision scheme have triggered several collider projects exploiting its potential. In particular, physics and accelerator communities are discussing new projects of a SuperB factory [5,6] and a SuperTau-Charm factory [7] with luminosities about 2 orders of magnitude beyond those achieved at the present B-[8] and Tau-charm factories [9].In this Letter we briefly introduce the CW concept, shortly discuss ...
This report presents the conceptual design of a new European research infrastructure EuPRAXIA. The concept has been established over the last four years in a unique collaboration of 41 laboratories within a Horizon 2020 design study funded by the European Union. EuPRAXIA is the first European project that develops a dedicated particle accelerator research infrastructure based on novel plasma acceleration concepts and laser technology. It focuses on the development of electron accelerators and underlying technologies, their user communities, and the exploitation of existing accelerator infrastructures in Europe. EuPRAXIA has involved, amongst others, the international laser community and industry to build links and bridges with accelerator science — through realising synergies, identifying disruptive ideas, innovating, and fostering knowledge exchange. The Eu-PRAXIA project aims at the construction of an innovative electron accelerator using laser- and electron-beam-driven plasma wakefield acceleration that offers a significant reduction in size and possible savings in cost over current state-of-the-art radiofrequency-based accelerators. The foreseen electron energy range of one to five gigaelectronvolts (GeV) and its performance goals will enable versatile applications in various domains, e.g. as a compact free-electron laser (FEL), compact sources for medical imaging and positron generation, table-top test beams for particle detectors, as well as deeply penetrating X-ray and gamma-ray sources for material testing. EuPRAXIA is designed to be the required stepping stone to possible future plasma-based facilities, such as linear colliders at the high-energy physics (HEP) energy frontier. Consistent with a high-confidence approach, the project includes measures to retire risk by establishing scaled technology demonstrators. This report includes preliminary models for project implementation, cost and schedule that would allow operation of the full Eu-PRAXIA facility within 8—10 years.
BackgroundHeart and coronary calcifications in hemodialysis patients are of very common occurrence and linked to cardiovascular events and mortality. Several studies have been published with similar results. Most of them were mainly cross-sectional and some of the prospective protocols were aimed to evaluate the results of the control of altered biochemical parameters of mineral disturbances with special regard to serum calcium, phosphate and CaxP with the use of calcium containing and calcium free phosphate chelating agents. The aim of the present study was to evaluate in hemodialysis patients classic and some non classic risk factors as predictors of calcification changes after one year and to evaluate the impact of progression on survival.Methods81 patients on hemodialysis were studied, with a wide age range and HD vintage. Several classic parameters and some less classic risk factors were studied like fetuin-A, CRP, 25-OHD and leptin. Calcifications, as Agatston scores, were evaluated with Multislice CT basally and after 12-18 months.ResultsCoronary artery calcifications were observed in 71 of 81 patients. Non parametric correlations between Agatston scores and Age, HD Age, PTH and CRP were significant. Delta increments of Agatston scores correlated also with serum calcium, CaxP, Fetuin-A, triglycerides and serum albumin. Logistic regression analysis showed Age, PTH and serum calcium as important predictors of Delta Agatston scores. LN transformation of the not normally distributed variables restricted the significant correlations to Age, BMI and CRP. Considering the Delta Agatston scores as dependent, significant predictors were Age, PTH and HDL. A strong association was found between basal calcification scores and Delta increment at one year. By logistic analysis, the one year increments in Agatston scores were found to be predictors of mortality. Diabetic and hypertensive patients have significantly higher Delta scores.ConclusionsProgression of calcification is of common occurrence, with special regard to elevated basal scores, and is predictive of survival. Higher predictive value of survival is linked to the one year increment of calcification scores. Some classic and non classic risk factors play an important role in progression. Some of them could be controlled with appropriate management with possible improvement of mortality.
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