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

Problems of measurement of dense plasma heating in laser shock-wave compression

Experimental results of heating measurements of matter carried out in a study of laser-driven shock waves in aluminum (Batani et al. 1997) are discussed. The measured temporal evolution of the "color" temperature of the rear surface of the target is compared with that computed by a numerical code. It has been established that the target preheating can substantially affect optical signal features recorded from the rear side of the target, and consequently influence upon the accuracy of temperature and pressure measurements of the material behind the shock wave front

Development of estimation method of probability of finding of ship is in the set stripe of motion

Одной из причин происшествий являются ошибки в решении задач определения местоположения объектов или необнаруженные сбои в работе навигационных систем. В настоящее время широкое применение получили космические навигационные системы, особенностью эксплуатации которых является учет влияние эффектов среды распространения радиоволн, почему и выдвигается ряд требований по оценке достоверности определения местоположения объектов. Вследствие чего в предлагаемой статье предложен метод определения достоверности координатной информации в процессе судовождения, одним из основных показателей которой является вероятность нахождения корабля в заданной полосе движения.Однією з причин випадків є помилки у вирішенні завдань визначення місця розташування об'єктів або невиявлені збоїв в роботі навігаційних систем. В даний час широке застосування отримали космічні навігаційні системи, особливістю експлуатації яких є врахування впливу ефектів середовища поширення радіохвиль, через що і висувається ряд вимог з оцінки достовірності визначення місця розташування об'єктів. Унаслідок чого в статті запропонований метод визначення достовірності координатної інформації в процесі судноводіння, одним з основних показників якої є імовірність знаходження корабля в заданій смузі руху.One of reasons of cases there are errors in the decision of tasks of location of location of objects or undiscovered failures in-process navigation systems. Presently wide application was got by space navigation systems, the feature of exploitation of which is an account of influence of effects of environment of distribution of radio waves, from what the row of requirements is pulled out from the estimation of authenticity of location of location of objects. As a result of what in the article the offered method of determination of authenticity of co-ordinate information in the process of navigator, one of basic indexes of which there is probability of finding of ship in the set stripe of motion

Two-dimensional thermal simulations of an aluminum beam stripper for experiments at SPIRAL2

International audienceBecause of the very high ion beam intensities which will become available with the advent of the new large scale facilities like SPIRAL2, the mechanical resistance of targets under beam impact has become a crucial problem due to the large specific power deposition by the projectile ions in the material. For experiments that require production of a specific higher charge state than the one produced by the LINAC, the beam stripper must remain intact during the experimental campaign over a long period of time. Numerical simulations have confirmed that a fixed stripper, which is continuously irradiated at the same spot, cannot be used and we propose an alternative scheme in which a wheel shaped aluminum stripper rotating at a rate of 2000 rpm is used. The thermal load on the material is substantially reduced because a much larger area is now irradiated and our first test of simulations show that a steady state temperature, which is safely below the melting temperature of aluminum, is achieved due to heat conduction and radiation losses from the heated material. 2012 Elsevier B.V. All rights reserved

Two-dimensional thermal simulations of aluminum and carbon ion strippers for experiments at SPIRAL2 using the highest beam intensities

International audienceIn this paper we report on two-dimensional numerical simulations of heating of a rotating, wheel shaped target impacted by the full intensity of the ion beam that will be delivered by the SPIRAL2 facility at Caen, France. The purpose of this work is to study heating of solid targets that will be used to strip the fast ions of SPIRAL2 to the required high charge state for the FISIC (Fast Ion-Slow Ion Collision) experiments. Strippers of aluminum with different emissivities and of carbon are exposed to high beam current of different ion species as oxygen, neon and argon. These studies show that carbon, due to its much higher sublimation temperature and much higher emissivity, is more favorable compared to aluminum. For the highest beam intensities, an aluminum stripper does not survive. However, problem of the induced thermal stresses and long term material fatigue needs to be investigated before a final conclusion can be drawn. (C) 2012 Elsevier B.V. All rights reserved