No abstract available

[en] Recently built electron storage rings provide very high transverse electron densities in their low-β insertions. This suggests the feasibility of laser action of an electron storage ring at optical and even shorter wavelengths. Using a semiclassical theory of induced synchrotron radiation, it is shown that special bending devices should in fact allow for light amplification in this spectral range. The special bending unit should be an electrostatic deflector, providing an intense electric field of Coulomb type. Lower wavelength limits for laser action are estimated using reported or design performances of SPEAR I and DORIS. For the latter machine this limit is of the order of 3000 A, provided that an electric field strength of 10 kV/cm could be achieved and that the deflector is placed in a low-β insertion. (auth)

No abstract available

[en] Japan's unique scenario for a neutrino factory is at present the only one that does not rely on ionisation cooling of the muon beam. This is made possible by the large intrinsic acceptances of the fixed field alternating gradient (FFAG) accelerators replacing the linacs and recirculators of the other scenarios. Nevertheless, it is shown, using basic cooling theory, that moderate cooling in the first FFAG could be beneficial for the overall muon yield. Moreover, a solution using Be windows in the radio-frequency accelerating cavities would improve their performance. Simulation results obtained with the ACCSIM code essentially corroborate the theoretical cooling predictions, although showing a yet unexplained emittance exchange mechanism between the transverse phase spaces

[en] The paper describes the CERN approach for a proton driver for a Neutrino Factory. Two main layouts are presented: the so-called CERN Reference Scenario, based on a 2.2 GeV linac and an alternative one, based on a 30 GeV synchrotron. Both produce bunches of 1 ns (r.m.s.) and a beam power of 4 MW

[en] Although Japan's unique FFAG scenario for a neutrino factory does not rely on ionization cooling of the muon beam, moderate cooling in the first FFAG could be beneficial for the overall muon yield and, perhaps even more important, reduce the final emittances in the decay ring. Using basic cooling theory, one can show that this appears possible. In the Nufact'01 contribution on 'ionization cooling in FFAGs', the addition of absorbers into the superconducting 0.3-1 GeV/c Japanese FFAG was investigated. The cooling absorbers were 7 mm beryllium sheets in the median plane of the RF cavities. Beryllium was chosen because Be windows are a known design to increase field strength and quality of large aperture cavities. Obviously metallic lithium or a sandwich of lithium hydride between thin metallic Be sheets is preferable to the cooling viewpoint. We have thus complemented the results for Be by equivalent inserts of pure lithium and lithium hydride. For each material two thicknesses were compared

[en] Loss concentration has become an ever more important issue in high-current machines for spallation sources, hadron facilities etc. A major problem in the design of the collimators is outscattering. It is shown how predeflectors of varying complexity can increase the average hitting depth, and thereby improve collection efficiency. The latter is further enhanced if the predeflection principle is combined with a premagnetised collector. Application to the CERN PS Booster and the TRIUMF KAON Accumulator Ring is discussed. (author) 8 refs.; 2 figs.; 2 tabs

[en] BEAMSCOPE (Betatron Amplitude Scraping by Closed Orbit Perturbation) is a device developed more than a decade ago at the CERN Proton Synchrotron Booster (PSB). Its main use is for fast, automated emittance measurements at any moment in the acceleration cycle but is also allows the display of the distribution of betatron amplitudes, physical or normalized. Experience gained over the years and problems encountered are presented and results are related to other types of emittance measurement devices. (author)

[en] A pulsed spallation neutron source, satisfying the increasing needs of material sciences, life sciences and medical research, has been considered by a study group of potential users and accelerator experts. The accelerator specifications for the spallation source are: proton beam power on target 200 kW; repetition rate ≤25 Hz; pulse length ≤ 1μs. The accelerator configuration preferred consists of two stages, where Stage 1 is an H-linac and a rapid-cycling (25 Hz) synchrotron in the GeV range providing an average beam power of 100 kW on the target. A number of upgrading possibilities with a view to reaching the design beam power is discussed for Stage 2 of the project. The possibility of 'parasitic' light ion acceleration for basic medical research is explored. (author) 9 refs.; 1 fig.; 2 tabs

[en] For efficient antiproton production, a maximum number of protons has to be concentrated within one quarter of the CERN Proton Synchrotron (PS) ring before sending the beam to the production target. Now, with the Antiproton Collector (AC) added to the Antiproton Accumulator (AA), the bunch length has to be shorter (about 20 ns) than before in order to allow bunch rotation in the AC. Whilst a more ambitious scheme providing such a beam is being implemented, a funneling method-where beams of two rings out of the four-ring Proton Synchrotron Booster (PSB) are recombined in pairs by means of an RF dipole that permits longitudinal interleaving of successive bunches-is in operation since the start-up of the AC. Preliminary experiments had shown that the PS space-charge limit had to be overcome in order to make the scheme feasible. Indeed, after raising the PSB output energy from 815 MeV to 1 GeV - with a rather modest effort - beams of > 10¹³ protons squeezed into one quarter of the PS ring were achieved. As a spin-off of this development, a new record proton beam for fixed-target physics was accelerated in the Super Proton Synchrotron (SPS), while beam losses in the PSB-PS line were reduced. Here we deal with this upgrading, give a short summary of past, present, and future p production beams in CERN, and discuss some trickier beam dynamics aspects of the very particular one obtained by funneling. 7 refs., 7 figs., 1 tab