Simulations of full impact of the Large Hadron Collider beam with a solid graphite target

The Large Hadron Collider (LHC) will operate with 7TeV/c protons with a luminosity of 1034cm−2s−1. This requires two beams, each with 2808 bunches. The nominal intensity per bunch is 1.15×1011 protons and the total energy stored in each beam is 362 MJ. In previous papers, the mechanisms causing equipment damage in case of a failure of the machine protection system was discussed, assuming that the entire beam is deflected onto a copper target. Another failure scenario is the deflection of beam, or part of it, into carbon material. Carbon collimators and beam absorbers are installed in many locations around the LHC close to the beam, since carbon is the material that is most suitable to absorb the beam energy without being damaged. In case of a failure, it is very likely that such absorbers are hit first, for example, when the beam is accidentally deflected. Some type of failures needs to be anticipated, such as accidental firing of injection and extraction kicker magnets leading to a wrong deflection of a few bunches. Protection of LHC equipment relies on the capture of wrongly deflected bunches with beam absorbers that are positioned close to the beam. For maximum robustness, the absorbers jaws are made out of carbon materials. It has been demonstrated experimentally and theoretically that carbon survives the impact of a few bunches expected for such failures. However, beam absorbers are not designed for major failures in the protection system, such as the beam dump kicker deflecting the entire beam by a wrong angle. Since beam absorbers are closest to the beam, it is likely that they are hit first in any case of accidental beam loss. In the present paper we present numerical simulations using carbon as target material in order to estimate the damage caused to carbon absorbers in case of major beam impac

Prospects of high energy density physics research using the CERN super proton synchrotron (SPS)

The Super Proton Synchrotron (SPS) will serve as an injector to the Large Hadron Collider (LHC) at CERN as well as it is used to accelerate and extract proton beams for fixed target experiments. In either case, safety of operation is a very important issue that needs to be carefully addressed. This paper presents detailed numerical simulations of the thermodynamic and hydrodynamic response of solid targets made of copper and tungsten that experience impact of a full SPS beam comprized of 288 bunches of 450 GeV/c protons. These simulations have shown that the material will be seriously damaged if such an accident happens. An interesting outcome of this work is that the SPS can be used to carry out dedicated experiments to study High Energy Density (HED) states in matte

Implosion of reactor-size, gas-filled spherical shell targets driven by shaped pressure pulses

Submitted to Phys. FluidsSIGLEITItal

Almacenamiento refrigerado de semillas de araucaria angustifolia (bert.) O. Kuntze: conservación del poder germinativo

Este trabajo fue realizado con el objetivo de establecer las condiciones adecuadas de almacenamiento refrigerado para conservar, durante 24 meses, el poder germinativo de las semillas de Araucaria angustifolia (Bert.) O. Kuntze. De esta manera se podrían sortear los inconvenientes causados por la ciclicidad en la producción de semillas y su característica recalcitrante, en tanto que, a su vez, permitiría la programación de la siembra, tanto en vivero como a campo. En dos años consecutivos, se realizaron dos ensayos con semillas recolectadas en el departamento Manuel Belgrano (Misiones, Argentina). Estas se envasaron en bolsas realizadas con las películas plásticas flexibles Etil vinil acetato (EVA) y Polietileno (PE), y se almacenaron en cámaras refrigeradas a -3, 0, 4 y 10ºC. A algunos envases se les adicionó aserrín (1:8 p/p). Las muestras de los empaquetamientos sin aserrín se extrajeron bimestralmente y las de los que contenían aserrín, cada cuatro meses. En los envases, se determinó pérdida de peso y concentración de CO2; mientras que, en las semillas, se evaluó contenido de humedad, contenido de almidón y capacidad germinativa. La mayor pérdida de peso se registró a 10ºC y la concentración de CO2 desarrollada en los envases empezó a aumentar, aproximadamente en el séptimo mes de almacenamiento. Durante el almacenamiento, las semillas registraron un aumento del contenido de humedad (10%) y una ligera disminución del contenido de almidón. Los mayores valores de germinación (P>0,05) se obtuvieron en las semillas de las bolsas realizadas con la película EVA y almacenadas a 0ºC. La adición de aserrín no mostró diferencias significativas. Los resultados obtenidos para los dos ensayos fueron similares. De esto, surge que, para mantener valores de germinación, de semillas de Araucaria angustifolia, iguales o superiores a los iniciales, por un período de 24 meses, resulta conveniente empaquetarlas con la película plástica EVA y almacenarlas a 0º

High energy density physics studies using intense particle beams at the FAIR facility at Darmstadt

High Energy Density (HED) physics spans over numerous areas of basic and applied physics, for example, astrophysics, planetary physics, geophysics, inertial fusion and many others. During the past fifteen years, great progress has been made on the development of bunched intense particle beams that have emerged as a novel tool for studying HED physics. In this paper we present two experiment designs that have been worked out for HED physics studies at the Facility for Antiprotons and Ion Research (FAIR) at Darmstadt. This facility has entered into construction phase and will provide one of the largest and most powerful particle accelerators in the world