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S. Roesler

Publications and source records attributed to S. Roesler.

At least 19 recordsLinked to original sources

Safety

Chapter 17 in High-Luminosity Large Hadron Collider (HL-LHC) : Preliminary Design Report. The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 7,000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total collisions created) by a factor ten. The LHC is already a highly complex and exquisitely optimised machine so this upgrade must be carefully conceived and will require about ten years to implement. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11-12 tesla superconducting magnets, compact superconducting cavities for beam rotation with ultra-precise phase control, new technology and physical processes for beam collimation and 300 metre-long high-power superconducting links with negligible energy dissipation. The present document describes the technologies and components that will be used to realise the project and is intended to serve as the basis for the detailed engineering design of HL-LHC.

physics.acc-ph

Update On The Code Intercomparison and Benchmark For Muon Fluence and Absorbed Dose Induced By An 18-GeV Electron Beam After Massive Iron Shielding

In 1974, Nelson, Kase and Svensson published an experimental investigation on muon shielding around SLAC high-energy electron accelerators. They measured muon fluence and absorbed dose induced by 14 and 18 GeV electron beams hitting a copper/water beamdump and attenuated in a thick steel shielding. In their paper, they compared the results with the theoretical models available at that time. In order to compare their experimental results with present model calculations, we use the modern transport Monte Carlo codes MARS15, FLUKA2011 and GEANT4 to model the experimental setup and run simulations. The results are then compared between the codes, and with the SLAC data.

physics.acc-ph

Path to AWAKE: Evolution of the concept

This report describes the conceptual steps in reaching the design of the AWAKE experiment currently under construction at CERN. We start with an introduction to plasma wakefield acceleration and the motivation for using proton drivers. We then describe the self-modulation instability --- a key to an early realization of the concept. This is then followed by the historical development of the experimental design, where the critical issues that arose and their solutions are described. We conclude with the design of the experiment as it is being realized at CERN and some words on the future outlook. A summary of the AWAKE design and construction status as presented in this conference is given in [1].

physics.plasm-ph

Radiation protection issues after 20 years of LHC operation

Since November 2009, the LHC commissioning progresses very well, both with proton and lead beams. It will continue in 2011 and nominal LHC operation is expected to be attained in 2013. In parallel, plans for various LHC upgrades are under discussion, suggesting a High-Luminosity (HL) upgrade first and a High-Energy (HE) upgrade in a later state. Whereas the upgrade in luminosity would require the modification of only some few key accelerator components like the inner triplets, the upgrade in beam energy from 7 TeV to 16.5 TeV would require the exchange of all dipoles and of numerous other accelerator components. The paper gives an overview of the radiation protection issues related to the dismantling of LHC components prior to the installation of the HE-LHC components, i.e. after about 20 years of LHC operation. Two main topics will be discussed: (i) the exposure of workers to ionizing radiation during the dismantling of dipoles, inner triplets or collimators and experiments and (ii) the production, conditioning, interim storage and final disposal of radioactive waste.

physics.acc-ph

A study of high-energy proton induced damage in Cerium Fluoride in comparison with measurements in Lead Tungstate calorimeter crystals

A Cerium Fluoride crystal produced during early R&D studies for calorimetry at the CERN Large Hadron Collider was exposed to a 24 GeV/c proton fluence Phi_p=(2.78 +- 0.20) x 10EE13 cm-2 and, after one year of measurements tracking its recovery, to a fluence Phi_p=(2.12 +- 0.15) x 10EE14 cm-2. Results on proton-induced damage to the crystal and its spontaneous recovery after both irradiations are presented here, along with some new, complementary data on proton-damage in Lead Tungstate. A comparison with FLUKA Monte Carlo simulation results is performed and a qualitative understanding of high-energy damage mechanism is attempted.

physics.ins-det

Secondary Cosmic Ray particles due to GCR interactions in the Earth's atmosphere

Primary GCR interact with the Earth's atmosphere originating atmospheric showers, thus giving rise to fluxes of secondary particles in the atmosphere. Electromagnetic and hadronic interactions interplay in the production of these particles, whose detection is performed by means of complementary techniques in different energy ranges and at different depths in the atmosphere, down to the Earth's surface. Monte Carlo codes are essential calculation tools which can describe the complexity of the physics of these phenomena, thus allowing the analysis of experimental data. However, these codes are affected by important uncertainties, concerning, in particular, hadronic physics at high energy. In this paper we shall report some results concerning inclusive particle fluxes and atmospheric shower properties as obtained using the FLUKA transport and interaction code. Some emphasis will also be given to the validation of the physics models of FLUKA involved in these calculations.

astro-ph

The hadronic models for cosmic ray physics: the FLUKA code solutions

FLUKA is a general purpose Monte Carlo transport and interaction code used for fundamental physics and for a wide range of applications. These include Cosmic Ray Physics (muons, neutrinos, EAS, underground physics), both for basic research and applied studies in space and atmospheric flight dosimetry and radiation damage. A review of the hadronic models available in FLUKA and relevant for the description of cosmic ray air showers is presented in this paper. Recent updates concerning these models are discussed. The FLUKA capabilities in the simulation of the formation and propagation of EM and hadronic showers in the Earth's atmosphere are shown.

hep-ph

d-Au and p-p collisions at RHIC and the multichain Monte Carlo Dpmjet-III

In this paper we compare systematically the two-component Dual Parton Model (DPM) event generator Dpmjet-III to d-Au and p-p data from RHIC. In this process we are able to improve the model. The need for fusion of chains and a recalibration of the model to obtain collision scaling in h-A and d-A collisions was found already in previous comparisons. Here, comparing to transverse momentum distributions of identified charged hadrons we find also the need to modify the transverse momentum distributions in the decay of hadronic strings, the basic building blocks of the model on soft hadronic collisions.

hep-ph

RHIC data and the multichain Monte Carlo DPMJET-II

Using data from RHIC we are able to systematically improve the two-component Dual Parton Model (DPM) event generator DPMJET-III. Introducing percolation parametrized as fusion of chains the model describes multiplicities and pseudorapidity distributions in nucleus-nucleus collisions at all centralities. Guided by the d-Au data from RHIC we recalibrate the model to obtain collision scaling in h-A and d-A collisions.

hep-ph

The physics models of FLUKA: status and recent development

A description of the intermediate and high energy hadronic interaction models used in the FLUKA code is given. Benchmarking against experimental data is also reported in order to validate the model performances. Finally the most recent developments and perspectives for nucleus-nucleus interactions are described together with some comparisons with experimental data.

hep-ph

The FLUKA code: present applications and future developments

The main features of the FLUKA Monte Carlo code, which can deal with transport and interaction of electromagnetic and hadronic particles, are summarised. The physical models embedded in FLUKA are mentioned, as well as examples of benchmarking against experimental data. A short history of the code is provided and the following examples of applications are discussed in detail: prediction of calorimetric performances, atmospheric neutrino flux calculations, dosimetry in atmosphere and radiobiology applications, including hadrontherapy and space radiation protection. Finally a few lines are dedicated to the FLUKA server, from which the code can be downloaded.

physics.comp-ph

Distributions of secondary muons at sea level from cosmic gamma rays below 10 TeV

The FLUKA Monte Carlo program is used to predict the distributions of the muons which originate from primary cosmic gamma rays and reach sea level. The main result is the angular distribution of muons produced by vertical gamma rays which is necessary to predict the inherent angular resolution of any instrument utilizing muons to infer properties of gamma ray primaries. Furthermore, various physical effects are discussed which affect these distributions in differing proportions.

astro-ph

Predicting Neutron Production from Cosmic-ray Muons

Fast neutrons from cosmic-ray muons are an important background to underground low energy experiments. The estimate of such background is often hampered by the difficulty of measuring and calculating neutron production with sufficient accuracy. Indeed substantial disagreement exists between the different analytical calculations performed so far, while data reported by different experiments is not always consistent. We discuss a new unified approach to estimate the neutron yield, the energy spectrum, the multiplicity and the angular distribution from cosmic muons using the Monte Carlo simulation package FLUKA and show that it gives a good description of most of the existing measurements once the appropriate corrections have been applied.

hep-ex

Baryon stopping in high energy collisions in the DPMJET-III model

A new striking feature of hadron production in nuclear collisions is the large stopping of the participating nucleons in hadron-nucleus and nucleus-nucleus collisions. This enhanced baryon stopping can be understood introducing new diquark breaking mechanisms in multistring models of hadron production. Here we discuss the implementation of these diagrams into the DPMJET-III hadronic Monte Carlo model.

hep-ph