Experimental Evidence of Beam Trapping with one-third and one-fifth Resonance Crossing

Beam trapping in stable islands of the horizontal phase space generated by non-linear magnetic fields is realized by means of a given tune variation so to cross a resonance of order n. Whenever the resonance is stable, n + 1 beamlets are created whereas if the resonance is unstable, the beam is split in n parts. Experiments at the CERN Proton Synchrotron showed protons trapped in stable islands while crossing the one-third and one-fifth resonance with the creation of 3 and 6 stable beamlets, respectively. The results are presented and discussed

Study of Beam Losses at Transition Crossing at the CERN PS

A series of studies has been carried out to understand and alleviate the beam losses in the CERN PS Proton Synchrotron. Losses appear especially at transition crossing during the pulsing of special quadrupoles used to create a gamma jump scheme. However, this causes a large optics and orbit distortion. After a brief summary of the gamma jump scheme at the PS, experimental and simulation results of the loss and reduction studies are presented

Adiabaticity and Reversibility Studies for Beam Splitting using Stable Resonances

At the CERN Proton Synchrotron, a series of beam experiments proved beam splitting by crossing the one-fourth resonance. Depending on the speed at which the horizontal resonance is crossed, the splitting process is more or less adiabatic, and a different fraction of the initial beam is trapped in the islands. Experiments prove that when the trapping process is reversed and the islands merged together, the final distribution features thick tails. The beam population in such tails is correlated to the speed of the resonance crossing and to the fraction of the beam trapped in the stable islands. Experiments and possible theoretical explanations are discussed

Progress in the Beam preparation for the Multi-Turn Extraction at the CERN Proton Synchrotron

A new type of extraction based on beam trapping inside stable islands in the horizontal phase space will become operational during 2008 at the CERN Proton Synchrotron. A series of beam experiments was carried out to prove lossless capture with high intensity and multi-bunched beams, up to $1.5 × 10^{13}$ protons per pulse, in preparation of the extraction commissioning. These fundamental steps for the new Multi-turn Extraction are presented and discussed in details

Il filtro di Wiener per la determinazione della superficie dinamica media degli oceani

Una superficie dinamica media degli oceani (Mean Dynamic Ocean Topography) globale è stata calcolata usando esclusivamente dati da satellite: il geoide è ottenuto da un modello di gravità basato sui dati del satellite GOCE, mentre la superficie media del mare (Mean Sea Surface) è ottenuta usando solo misure altimetriche. Poiché il modello di gravità considerato (TIMR5) è disponibile fino a grado e ordine 280, la corrispondente MDT deve essere filtrata consistentemente. In particolare la MDT viene rappresentata in serie di armoniche sferiche e successivamente filtrata applicando il principio di minimizzazione di Wiener. La rappresentazione in armoniche sferiche richiede di avere valori su tutta la superficie terrestre e non soltanto sulla superficie degli oceani, è quindi necessario coprire la superficie dei continenti con valori fittizi. Per questo scopo è stata adottata una procedura di riempimento tale da garantire che il segnale globale abbia la stessa covarianza del segnale solo sugli oceani. Infine, propagando l’errore del geoide e della MSS, sono state calcolate le matrici di varianza-covarianza della MDT stessa e delle velocità geostrofiche da questa derivate

Physics Potential of Very Intense Conventional Neutrino Beams

The physics potential of high intensity conventional beams is explored. We consider a low energy super beam which could be produced by a proposed new accelerator at CERN, the Super Proton Linac. Water Cherenkov and liquid oil scintillator detectors are studied as possible candidates for a neutrino oscillation experiment which could improve our current knowledge of the atmospheric parameters and measure or severely constrain the parameter connecting the atmospheric and solar realms. It is also shown that a very large water detector could eventually observe leptonic CP violation. The reach of such an experiment to the neutrino mixing parameters would lie in-between the next generation of neutrino experiments (MINOS, OPERA, etc) and a future neutrino factory.Comment: Talk given at the Venice Conference on Neutrino Telescopes, Venice, March, 200

GEANT4 simulation of phase rotation for neutrino factory

We discuss a GEANT4 simulation of the phase rotation system for a neutrino factory. The comparison with the beam transport code PATH shows a good agreement. Preliminary results for the energy disposition in the cryostat of the superconducting 1.8 T solenoid are briefly presented

1951–2017 changes in the frequency of days with visibility higher than 10 km and 20 km in Italy

Daily visibility records of the Italian Air Force synoptic stations over the 1951\u20132017 period have been used to set up a monthly quality/homogeneity checked dataset of fraction of days with visibility higher than or equal to 10 km (fVV10) and 20 km (fVV20) at 12 UTC. This dataset has been used to calculate regional average fVV10 and fVV20 records for 5 Italian climatic regions. The fVV10 and fVV20 averages show a strong spatial variability with the lowest values in the Po plain, one of the most polluted areas of Europe. In agreement with the results reported in literature for Europe, fVV10 and fVV20 show a positive trend over the whole considered period due to a strong increase starting in the 1980s. Differently, in the previous period, visibility decreases. Moreover, moving from low level areas to mid and high level ones the trends become much weaker, highlighting how the signal decreases with elevation. The analyses performed removing the days with high relative humidity or considering only the clear-sky days show that relative humidity and cloudiness do not have any effect on the observed trends, suggesting that the main driving factor is aerosol load. This hypothesis is supported by the comparison of visibility records with modelled aerosol concentrations, atmospheric optical depth values and emission records. Finally, the trends of fVV10 and fVV20 are in very good agreement with Italian regional records of other variables linked to atmospheric turbidity, like sunshine duration and surface solar radiation