| Paper |
Title |
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| TUPLS045 |
Completion of the Commissioning of the Superconducting Heavy Ion Injector PIAVE at INFN-LNL
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1597 |
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- G. Bisoffi, G. Bassato, A. Battistella, l. Boscagli, A. Calore, S. Canella, D. Carlucci, M. Cavenago, F. Chiurlotto, M. Comunian, M. De Lazzari, A. Facco, E. Fagotti, A. Galatà, P. Modanese, M.F. Moisio, A. Pisent, M. Poggi, A.M. Porcellato, P.A. Posocco, C. Roncolato, E. Sattin, S. Stark
INFN/LNL, Legnaro, Padova
- N. Schiccheri
CNAO Foundation, Milan
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At INFN-LNL the commissioning of the injector PIAVE, based on superconducting RFQs, has been completed. All the superconducting cavities (two RFQs and 8 quarter wave resonators - QWR) have shown very satisfactory stability with respect to changes of the liquid helium pressure and microphonics. Beam parameters are very close to the nominal values. The commissioning was completed by accelerating the pilot beam 16O3+ with the PIAVE injector and the booster linac ALPI (summer 2005). Since December 2005, a number of test beams were accelerated (mainly noble gas species) with PIAVE and ALPI and delivered to user experimental stations. Regular operation will be scheduled from Fall 2006 onwards.
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| TUPLS105 |
Sputter Probes and Vapor Sources for ECR Ion Sources
|
1744 |
| |
- M. Cavenago, A. Galatà, M. Sattin
INFN/LNL, Legnaro, Padova
- T. Kulevoy, S. Petrenko
ITEP, Moscow
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Sputter probes are a promising method for injecting controlled quantities of metallic elements inside ECRIS ion source, provided that sputter rate can be controlled, so that high charge states and low sample consumption rate will be attained. Moreover pressure at the probe and inside source should be different. With a simple differential pumping scheme and a sputter probe at 25 mm from ECRIS plasma, a 200 nA current of 120Sn18+ was easily obtained. Typical results (for Sn and Ti) of an inductively heated rf oven are discussed for comparison. Improvements of sputter probe concept and geometry are also described.
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| WEPCH126 |
Issues in Modelling of Negative Ion Extraction
|
2218 |
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- M. Cavenago
INFN/LNL, Legnaro, Padova
- V. Antoni, F. Sattin
CNR/RFX, Padova
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In the context of negative ion sources proposed for neutral beam injectors for tokamaks, halo of the extracted beam is typically large (about 10 %) and optimum shape of the multiaperture extraction electrode is a matter of research. Present designs range from an aperture angle of 45 degree (low current, convergent beam) to 90 degrees (flat electrode, high current, large divergence and halo). Two major difficulties of the beam extraction modelling are here discussed. First, the generation processes of negative ion show some shortcomings: volume production seems low; wall production is large, but ions have wrong directions and/or large nonuniformity in current density; elastic scattering of wall generated ions into the extraction direction must compete with mutual neutralization. Second, the plasma sheath charge has to be negative on the extraction hole surface and positive on the nearby wall surface, which enhances beam aberration near hole edge. After discussing limitation of existing codes and model, result from an ad hoc code are discussed. Also 2D equation for the selfconsistent electrostatic field can be written and implemented into a multiphysics general purpose program.
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| WEPLS050 |
Experiments with Electron Cloud and Sources
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2490 |
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- M. Cavenago
INFN/LNL, Legnaro, Padova
- G. Bettega, F. Cavaliere, D. Ghezzi, A. Illiberi, R. Pozzoli, M. Rome
INFN-Milano, Milano
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The Penning-Malmberg trap ELTRAP installed at University of Milano can provide electron clouds of several sizes for study of non-linear physics: length ranges from 0.15 to 1 m, while diameter is varied between 25 mm and 70 mm by changing the electron source: filament or planar spiral. Vortices develop both in trapped and flowing electron beams. Slow instabilities, due to the accumulation of ions inside the trap are observed and cured by clearing fields. Results as a function of plasma size are described. Plan to install a third laser modulated electron source and additional diagnostic are also summarized.
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