The LHCf experiment: modelling cosmic rays at LHC

The LHCf experiment will be installed in 2007 on the LHC collider in the forward direction at 140 m. from the ATLAS interaction point. The purpose of LHCf is to precisely measure the pion production cross section near zero degrees through the measurement of the photons produced in neutral pion decay. This measurement is crucial for the simulation of the showers induced in the atmosphere by very high energy cosmic rays; the 14 TeV energy available in the center of mass frame corresponds in fact to an equivalent energy of 10(17) eV in the laboratory system. The paper focus on the proposed experiment and on the physics results that we expect from i

El desafiament pel coneixement. És l'LHC segur?

The Quest for Knowledge. Is the LHC safe?Experimental Particle Physics using accelerators has currently reached an exciting moment, with the upcoming launch of the Large Hadron Collider (LHC) at the European Laboratory for Particle Physics (CERN). Nonetheless, public opinion has welcomed the news of this research tool with interest but at the same time with reservations

High-Gradient RF laboratory at IFIC for medical applications

General interest has been shown over the last years for compact and more affordable facilities for hadron-therapy. The High-Gradient (HG) know-how and technology for normal-conducting accelerating RF (Radio-Frequency) electron linac (linear accelerator) structures recently developed for projects such as CLIC (CERN), has raised the achievable accelerating gradient from 20-30 MV/m up to 100-120 MV/m. This gain has come through a better understanding of the high-power RF vacuum arcs or breakdowns (BD) phenomena, the development of quantitative HG RF design methods and refinements in fabrication techniques. This can allow for more compact linacs also for protons, which is potentially important in the new trend in hadron-therapy of using linacs able to provide protons of 70-230 MeV or light ions of 100-400 MeV/u. Linacs are of particular interest for medical applications because they can provide a high degree of flexibility for treatment, such as running at 100-400 Hz pulse rate and pulse-to-pulse beam energy (and intensity) variations. This kind of accelerator is very well suited to treat moving organs with 4D multi-painting spot scanning technique. HG operation is limited by the BD phenomena and is characterized by the BD-Rate. New fresh structures initially operate at a reduced performance and must be conditioned through extended high-power rf operation until the maximum operational gradient is reached. This process is a time consuming, and consequently costly task (> 350 million pulses) which is important to understand and reduce. The IFIC HG-RF laboratory is designed to host a high-power and high-repetition rate facility for testing S-Band (2.9985 GHz) normal-conducting RF structures. This facility will allow the development, RF conditioning and studies of the BD phenomena in HG structures.General interest has been shown over the last years for compact and more affordable facilities for hadron-therapy. The High-Gradient (HG) know-how and technology for normal-conducting accelerating RF (Radio-Frequency) electron linac (linear accelerator) structures recently developed for projects such as CLIC (CERN), has raised the achievable accelerating gradient from 20-30 MV/m up to 100-120 MV/m. This gain has come through a better understanding of the high-power RF vacuum arcs or breakdowns (BD) phenomena, the development of quantitative HG RF design methods and refinements in fabrication techniques. This can allow for more compact linacs also for protons, which is potentially important in the new trend in hadron-therapy of using linacs able to provide protons of 70-230 MeV or light ions of 100-400 MeV/u. Linacs are of particular interest for medical applications because they can provide a high degree of flexibility for treatment, such as running at 100-400 Hz pulse rate and pulse-to-pulse beam energy (and intensity) variations. This kind of accelerator is very well suited to treat moving organs with 4D multi-painting spot scanning technique. HG operation is limited by the BD phenomena and is characterized by the BD-Rate. New fresh structures initially operate at a reduced performance and must be conditioned through extended high-power rf operation until the maximum operational gradient is reached. This process is a time consuming, and consequently costly task (> 350 million pulses) which is important to understand and reduce. The IFIC HG-RF laboratory is designed to host a high-power and high-repetition rate facility for testing S-Band (2.9985 GHz) normal-conducting RF structures. This facility will allow the development, RF conditioning and studies of the BD phenomena in HG structures

Multipole compensation scheme for LHC low-beta insertions

The LHC dynamic aperture in Physics conditions is determined by the field errors in the low-b quadrupoles and these errors set a lower limit to the value of b*. The associated aberrations have been computed with the transfer matrix method which gives particularly simple and efficient formulae for the case of low-b insertions. These formulae have been applied to the LHC case to design a multipole compensation system. The efficiency of the method has been assessed by trajectory tracking