Ionisation profile monitor tests in the SPS

A beam profile monitor, from DESY, based on the ionisation of the rest gas, was installed in the SPS in 1997. Horizontal beam profiles obtained from the extracted positive ions are presented. It is known that in this case some broadening affects the signal, which limits the monitor resolution. This broadening results from the transverse momentum that the ions gain within the space charge field of the circulating beam. In order to improve the resolution for LHC applications, the monitor was modified during the 1998/99 winter stop. A magnetic focusing was incorporated. The aim is to analyse the signal provided by collecting the electrons, rather than the ions, of the ionised rest gas. The details of this new set-up and the expectations for the resolution limit will be compared to the measurement results

Quartz wires versus carbon fibres for improved beam handling capacity of the LEP wire scanners

After the first investigations performed in 1994, the study of thermal effects on Carbon and Quartz wires has been pursued in 1995. Carbon wires of 8 µm have been studied. Light emission resulting from the two heating mechanisms, electromagnetic fields and collision losses with the beam, were observed. Quartz wires of 10 and 30 µm were investigated and light emission due to the heating by collision with the beam was observed. The heat pattern differs completely from that of Carbon fibres. The Quartz wires withstood at 20 GeV circulating currents of at least 8 mA, the 1995 operational level in LEP. Quantitative evaluations and the influence of various dissipation processes are presented with the aim of evaluating a beam current limit

Cosmic rays studied with a hybrid high school detector array

The LORUN/NAHSA system is a pathfinder for hybrid cosmic ray research combined with education and outreach in the field of astro-particle physics. Particle detectors and radio antennae were mainly setup by students and placed on public buildings. After fully digital data acquisition, coincidence detections were selected. Three candidate events confirmed a working prototype, which can be multiplied to extend further particle detector arrays on high schools.Comment: 10 pages, 6 figures. Nigl, A., Timmermans, C., Schellart, P., Kuijpers, J., Falcke, H., Horneffer, A., de Vos, C. M., Koopman, Y., Pepping, H. J., Schoonderbeek, G., Cosmic rays studied with a hybrid high school detector array, Europhysics News (EPN), Vol. 38, No. 5, accepted on 22/08/200

Sensitivity Studies with the SPS Rest Gas Profile Monitor

During the SPS run in the year 2000 further test measurements were performed with the rest gas monitor. First, profiles of single circulating proton bunches were measured and the bunch charge progressively reduced, in order to determine the smallest bunch intensity which can be scanned under the present operating conditions. The image detector in this case was a CMOS camera. Using a multi-anode strip photo-multiplier with fast read-out electronics, the possibility to record profiles on a single beam passage and on consecutive turns was also investigated. This paper presents the results of these tests and discusses the expected improvements for the operation in 2001. Moreover, the issue of micro channel plate ageing effects was tackled and a calibration system based on electron emission from a heating wire is proposed. The gained experience will be used for the specification of a new monitor with optimised design, to be operated both in the SPS and in the LHC

Consistency of the Shannon entropy in quantum experiments

The consistency of the Shannon entropy, when applied to outcomes of quantum experiments, is analysed. It is shown that the Shannon entropy is fully consistent and its properties are never violated in quantum settings, but attention must be paid to logical and experimental contexts. This last remark is shown to apply regardless of the quantum or classical nature of the experiments.Comment: 12 pages, LaTeX2e/REVTeX4. V5: slightly different than the published versio

Nonperturbative Vertices in Supersymmetric Quantum Electrodynamics

We derive the complete set of supersymmetric Ward identities involving only two- and three- point proper vertices in supersymmetric QED. We also present the most general form of the proper vertices consistent with both the supersymmetric and U(1) gauge Ward identities. These vertices are the supersymmetric equivalent of the non supersymmetric Ball-Chiu vertices.Comment: seventeen pages late

Mechanical similarity as a generalization of scale symmetry

In this paper we study the symmetry known as mechanical similarity (LMS) and present for any monomial potential. We analyze it in the framework of the Koopman-von Neumann formulation of classical mechanics and prove that in this framework the LMS can be given a canonical implementation. We also show that the LMS is a generalization of the scale symmetry which is present only for the inverse square potential. Finally we study the main obstructions which one encounters in implementing the LMS at the quantum mechanical level.Comment: 9 pages, Latex, a new section adde

Regarding: ‘Explorative study to identify novel candidate genes related to oxaliplatin efficacy and toxicity using a DNA repair array'

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