Transverse Beam Profiles

The performance and safe operation of a particle accelerator is closely connected to the transverse emittance of the beams it produces. For this reason many techniques have been developed over the years for monitoring the transverse distribution of particles along accelerator chains or over machine cycles. The definition of beam profiles is explained and the different techniques available for the detection of the particle distributions are explored. Examples of concrete applications of these techniques are given.Comment: 37 pages, 53 figure

Historia de la Investigación en el Alto Atlas. Pasado y presente de la investigación en el valle de Oukaïmeden

The present paper gives a brief account of the history of rock art research in Morocco from the late 19th century to the present, with special emphasis in two periods: the French colonial protectorate and the post-colonial period, after the Morocco independence in 1956 and the creation of the Moroccan Heritage Institute in the mid 80’s, with special attention to the seminal work of the French researcher Jean Malhomme.El presente artículo ofrece un breve resumen de la historia de la investigación del arte rupestre de Marruecos, desde fines del s.XIX a la actualidad, con énfasis especialmente en dos periodos: el del Protectorado colonial francés y el postcolonial, tras la independencia de Marruecos y la creación del Instituto de Patrimonio de Marruecos a mediados de los años 80, con especial énfasis en el trabajo pionero del investigador francés Jean Malhomme

High Resolution Transverse Profile Measurement

The performance of a particle accelerator is in large part defined by the transverse emittance of the beams. In most cases, like colliders and light sources (Synchrotrons or Free Electron Lasers), the quality of the final product, i.e. luminosity and brilliance, is directly linked to this parameter. For this reason many techniques and devices have been developed over the years for monitoring the transverse distribution of particles along accelerator chains or over machine cycles. Moreover modern designs of accelerators allow smaller size and/or higher current beams. New, more demanding, emittance measurement techniques have to be introduced and existing ones expanded. This presentation will review the different methods and the different instruments developed so far

Dead time effect on single photon counting for the longitudinal density monitor of LHC

The longitudinal distribution of the protons in the two LHC rings needs to be known with high accuracy. This is required for both: the correct operation of the machine and the understanding of beam dynamics effects that can influence the performances of the collider. One possible way of achieving the required time resolution of 50 ps and dynamic range of 10.4 is single photons counting of the synchrotron radiation emitted by the beams using avalanche photo diodes (APDs). Although this kind of devices have very short rise times and allow precise time stamping of detected photons, they also have long recovery times (dead time) of the order of hundreds of nanoseconds, much longer than the bunch length of the LHC beams. For this reason it is important to evaluate the masking effect introduced by this dead time, where photons emitted by protons in different longitudinal positions will have different probabilities of being detected

First Results from the LHC Beam Instrumentation Systems

During the 2008 LHC injection synchronisation tests and the subsequent days with circulating beam, the majority of the LHC beam instrumentation systems were capable of measuring their first beam parameters. This included the two large distributed systems, beam position and beam loss, as well as the scintillating and OTR screens, the fast and DC beam current transformers, the tune monitors and the wire scanners. The fast timing system was also extensively used to synchronise most of this instrumentation. This paper will comment on the results to date