No abstract available

[en] We studied the possibility of the occurrence of transverse instability induced by trapped electrons in unbunched beams in the Proton Storage Ring and the proposed Advance Hadron Facility (AHF) at Los Alamos, as well as in the proposed Kaon Factory at TRIUMF. We found that the e-p instability may be possible for unbunched beams in the PSR but is unlikely to occur in the advanced hadron facilities. 8 refs., 4 figs

[en] Coulomb crystals in storage rings have been studied theoretically but not observed experimentally. We review here some aspects of the theory of crystalline beams and show that the main requirement to achieve crystallization is not fulfilled by existing storage rings

[en] The ability to accelerate polarized protons up to the final energy is one of the main objectives of EHF and strongly influences, together with the requirements of beam stability and minimum beam losses, the design of the accelerator complex. In particular the transfer energy between Booster and Main Ring has been selected to enable the use of Siberian Snakes as a global cure of resonant depolarization in the Main Ring

[en] In this paper after a short introduction on the main concepts of spin dynamics, like the conservation of the polarization as a stability condition, the depolarizing resonances and their care by the Siberian Snake schema, two particular applications are discussed. In the European hadron Facility, and in the other future hadron machines in the same range of energies (30--40 Gev), the polarization in the main ring can be maintained using a Siberian Snake. We shall discuss the design of such a device. As a second example is considered the Spin Splitter, a proposed experiment with the aim of polarizing bar p. Also in this case the spin stability is realized by the Siberian Snake schema

[en] A new injector for the superconducting linac ALPI is under construction at LNL. This linac (called PIAVE) will be able to accelerate ions up to uranium, for an equivalent voltage of about 8 MV, and will improve the performances of ALPI (presently injected by a 15 MV Tandem) both in intensity and ions species availability. We shall discuss the design choices adopted for PIAVE, with the use of two compact 80 MHz superconducting RFQ up to about 530 keV/u, followed by eight independently phased QWR (minor modification of those already installed in ALPI). This approach, made possible by a rather sophisticated beam dynamics design, allowed to concentrate the R and D effort on the development of the RFQ structure. Details like the optimization of the acceleration in the RFQ, the bunching system and the transition between the two RFQs will be discussed

[en] In the design of the European Hadron Facility great emphasis has been put not only on the production of a high intensity beam (100 μA) but also on the capability to accelerate polarized proton beams up to final energy (30 GeV). In this paper the authors describe both the expected depolarizing effects and the planned correction methods. While the authors propose to use in the case of the EHF Booster conventional correction methods like harmonic spin matching and fast tune jumps, we suggest in the case of the Main Ring a pair of Siberian Snakes as cure for resonant depolarization. For the selection and the design of different types of Siberian Snakes we analyzed both the spin and orbit behaviour in the magnetic fields of various snakes

[en] An essential problem for the successful operation of high current linear ion accelerators is the control of beam losses due to halo particles. As a possible mechanism for the formation of such a halo we concentrate on the interplay between intrabeam scattering (IBS) and the incidence of particles which are driven to high amplitudes by resonances with the nonlinear space charge fields of a mismatched beam. Since a fully microscopic numerical treatment including all the mutual Coulomb interactions between the beam ions requires much too high computational effort, we developed an approximative method. These particle-core-molecular-dynamics (PCMD) simulations suitably join the mean-field description of the time evolution of the beam in framework of the envelope equations and a microscopic calculation of the Coulomb interactions between pseudo-particles with a renormalized charge. With this method we studied matched and mismatched continuous KV-beams in a FODO channel. In first simulation runs we observed a significant difference in the formation of a cloud of particles around the beam core between matched and mismatched beams when IBS is present. While for a matched beam with IBS no particles with increasing amplitudes have been found, such particles appear at the same IBS rate for a mismatched beam. These results suggest that in a mismatched beam even rather small IBS rates seem to act as a non-negligible source for a halo formation. To conclude from these observations on intense real beams in a high current linac needs, however, further verification of the proposed PCMD method

[en] For improved reliability, the front-end of the LEP Injector Linac (LIL) has been replaced. The new system has been used for LEP runs, since March 1991. The experimental results presented here show a significant improvement of beam characteristics. These results also agree well with those of the simulation programs

[en] The synchrotron of the ADRIA project, proposed for the upgrading of LNL accelerator complex, have the capability to accelerate protons with an injection energy of 210 MeV, repetition rate of 50 Hz and an average current of about 32 μA. In this paper we shall spell out a new proposal for the H^- injector in this mode of operation. The main components of the linac are a double frequency (32.5 MHz, 65 MHz), an RFQ and DTL cavities (425 MHz). The buncher gives to the bunch sequences the time structure corresponding to the Synchrotron RF frequency at injection. The shunt impedance in DTL cavities (equipped with rare earth quadrupoles) remains sufficiently high up to the synchrotron injection energy. (author). 6 refs., 6 tabs., 1 fig