Study of losses during Continuous Transfer Extraction at CERN Proton Synchrotron

The proton beams used for the fixed target physics at the SPS are extracted from the PS at 14 GeV/c in five turns, using a technique called Continuous Transfer (CT). During this extraction, large losses are observed in straight sections were the machine aperture should be large enough to accommodate the circulating beam without any loss. These losses are due to particles scattered by the electrostatic septum used to slice the beam and defocused by a quadrupole used during the extraction. Simulations and experimental results are presented

Beam losses in the PS during CT extraction

The proton beams used for the fixed target physics at the SPS are extracted from the PS at 14 GeV/c in five turns, using a technique called Continuous Transfer (CT). During this extraction, large losses are observed in straight sections were the machine aperture should be large enough to accommodate the circulating beam without any loss. These losses are due to particles scattered by the electrostatic septum used to slice the beam and defocused by a quadrupole used during the extraction. Simulations and experimental results are presented

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

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

Study of Beam Losses at Injection in the CERN Proton Synchrotron

The maximum intensity the CERN PS has to deliver is continuously increasing. In particular, during the next years, one of the most intense beams ever produced in the PS, with up to 3000 1010 proton per pulse, should be delivered on a regular basis for the CNGS physics program. It is now known that the existing radiation shielding of the PS in some places is too weak and constitutes a major limitation due to large beam losses in specific locations of the machine. This is the case for the injection region: losses appear on the injection septum when the beam is injected in the ring and during the first turn, due to an optical mismatch between the injection line and the PS. This paper presents the experimental studies and the simulations which have been made to understand the loss pattern in the injection region. Possible solutions to reduce the beam losses will be described, including the computation of a new injection optics

Radioactive ion beams produced by neutron-induced fission at ISOLDE

The production rates of neutron-rich fission products for the next-generation radioactive beam facility EURISOL are mainly limited by the maximum amount of power deposited by protons in the target. An alternative approach is to use neutron beams to induce fission in actinide targets. This has the advantage of reducing: the energy deposited by the proton beam in the target; contamination from neutron-deficient isobars that would be produced by spallation; and mechanical stress on the target. At ISOLDE CERN, tests have been made on standard ISOLDE actinide targets using fast neutron bunches produced by bombarding thick, high-Z metal converters with 1 and 1.4 GeV proton pulses. This paper reviews the first applications of converters used at ISOLDE. It highlights the different geometries and the techniques used to compare fission yields produced by the proton beam directly on the target with neutron-induced fission. Results from the six targets already tested, namely UC2/graphite and ThO2 targets with tungsten and tantalum converters, are presented. To gain further knowledge for the design of a dedicated target as required by the TARGISOL project, the results are compared to simulations, using the MARS code interfaced with MCNP libraries, of the neutron flux from the converters interacting with the actinide targets

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