| Paper | Title | Page |
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| WEPP053 | Beam Transport in Toroidal Magnetic field | 2641 |
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| The concept of a storage ring with toroidal magnetic field was presented in the two previous EPAC conferences. Here we report the first results of experiments performed with beam transport in toroidal magnetic fields and details of the injection system. The beam transport experiments were carried out with 30 degree toroidal segments with an axial magnetic field of 0.6T. The space charge force and dynamics of a proton beam near the brillouin flow limit are presented here. The multiturn injection system relies on a specified injection coil together with an electric kicker system. The scaling law for the complete storage ring is discussed. The advantages and disadvantages for such a stellarator type storage ring on the 5T level will be reviewed. | ||
| THPC104 | Optical Diagnostic on Gabor Plasma Lenses | 3221 |
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| Gabor lenses have been built and successfully been used for the focussing of particle beams. In the case of a positive ion beam the space charge of the confined electron cloud may cause an over compensation of the ion beam space charge force and consequently focus the beam. The nonneutral plasma (NNP) is influenced by the external fields and its current state can be determined by the beam emittance growth. Experiments using a high field Gabor lens have shown a correlation between the thermalization of the enclosed electron cloud and the focussing quality. A three segmented Gabor lens was constructed recently for a more detailed investigation of the plasma parameters as a function of the external fields. The commissioning of the lens has been finished successfully and the light emitted by the interaction between the electron cloud and the residual gas has been observed. In a next step the experiments will concentrate on the spectral analyses of the emitted light to evaluate the temperature and density distribution of the confined NNP. Experimental results will be presented in comparison with numerical simulation. | ||
| THPP091 | One Nano-second Bunch Compressor for High Intense Proton Beam | 3578 |
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About ten bunches of 2MeV proton rf-linac with an average current of 150mA at 175 MHz will be deflected by kicker on different paths into a magnetic bending system. Passing this optimized geometry they approach each other longitudinaly (βλ = 0.114m) and arrive at the same time at the focus of the dipole system. For longitudinal focussing of the merged bunches a rebuncher cavity is included in the bending system. The motivation and the layout of the whole project, "Frankfurter Neutronen Quelle am Stern-Gerlach Zentrum" (FRANZ), were presented in details in previous conferences*,**. More accurate investigation results in a revision of the preliminary concept. For a theoretical proof of principle one trajectory with the biggest path length of a new geometry is calculated by a multi particle beam dynamics program (LORASR). Preliminary investigations showed, that magnetic fringing fields and bunch-bunch interactions have to be included as detailed as posible in the beam simulations. In this paper the beam dynamics results from LORASR-simulations, the new geometry and the code development for the bunch compressor are discussed in details.
*L. P. Chau et al. Proc. of the Eur. Part. Acc. Conf., Edinburgh (2006), 1690-1692. |
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| THPP111 | A 250 kHz Chopper for Low Energy High Intensity Proton Beams | 3623 |
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| A neutron pulse with 1 ns pulse length and a repetition rate of 250 kHz is needed for the experiments on nuclear astrophysics using the Frankfurter Neutron source at the Stern-Gerlach-Zentrum. The time structure of the neutron flux is given by the primary proton beam witch hits a 7Li target. The creation of the required time structure on an intense proton beam of 200 mA dc with respect to emittance growth and beam losses is demanding. The pulsing of the ion source depends on the rise time of the plasma whereas the pulsing of the extraction voltage leads into high power deposition into the multi aperture extraction system. On the other hand a chopper system downstream of the RFQ results in rf power consumption due to beam loading and the problem of beam dumping at a beam power of several kW. Therefore it is planed to install a chopper as part of a resonant circuit in the LEBT – section consisting of four solenoids. Two different methods, magnetic and electric deflection, will be discussed with respect to emittance growth, beam losses and the influence on space charge compensation processes. Numerical simulations and preliminary results of experiments will be presented and compared. |