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| TUAZ01 |
Overview of recent halo diagnosis and non-destructive beam profile monitoring
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electron, synchrotron, laser, radiation |
54 |
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- K. Wittenburg
DESY, Hamburg
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Beam profile (emittance) and beam halo are characteristic properties of high-intensity and high energy beams that might limit the performance of the adjacent accelerator. Therefore a reliable measurement and determination of these parameters is most helpful for understanding, tuning and improvement of the whole accelerator chain to achieve the best (at least the design-) performance. This talk will give an overview over recent instruments used for non-destructive beam profile and halo monitoring and will discuss their limits, experiences and latest improvements.
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| THAW02 |
New experimental measurements of electron clouds in ion beams with large tune depression*
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electron, quadrupole, ion, simulation |
288 |
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- A. W. Molvik, R. H. Cohen, A. Friedman, M. Kireeff Covo
LLNL, Livermore, California
- F. M. Bieniosek, P. A. Seidl, J.-L. Vay
LBNL, Berkeley, California
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We study electron clouds in high perveance beams (K = 8E-4) with a large tune depression of 0.2 (defined as the ratio of a single particle oscillation response to the applied focusing fields, with and without space charge). These 1 MeV, 180 mA, K+ beams have a beam potential of +2 kV when electron clouds are minimized. Simulation results are discussed in a companion paper [J-L. Vay, this Conference]. We have developed the first diagnostics that quantitatively measure the accumulation of electrons in a beam [M. Kireeff Covo, et al., to be submitted to Phys. Rev. Lett.]. This, together with measurements of electron sources, will enable the electron particle balance to be measured, and electron-trapping efficiencies determined. We measure and simulate ~10 MHz electron oscillations in the last quadrupole magnet when we flood the beam with electrons from an end wall. Experiments where the heavy-ion beam is transported with solenoid magnetic fields, rather than with quadrupole magnetic or electrostatic fields, are being initiated. We will discuss the initial results using electrode sets (in the middle and at the ends of magnets) to either expel or to trap electrons within the magnets.
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| THAW04 |
Experimental Characterization of the “1st Pulse” e-p Instability at the LANL PSR
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electron, accumulation, injection, controls |
311 |
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- R. J. Macek, A. A. Browman, D. H. Fitzgerald, R. C. McCrady, T. Spickermann, J. Zaugg
LANL, Los Alamos, New Mexico
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A puzzling aspect of the e-p instability at PSR is the so called “1st Pulse” instability phenomenon. It shows up on the first beam pulse after a period (10 to 30 minutes or more) of beam off time. This pulse has a significantly lower threshold than subsequent beam pulses that follow with the standard time separation. While the standard PSR operation for Lujan Center operation is unaffected by this phenomenon, it does interfere with some high intensity, single pulse experiments using PSR beam. We will summarize the present experimental data characterizing this phenomenon as compared with the typical e-p instability observed at higher repetition rates at PSR and discuss some possible explanations.
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| THAZ01 |
Experience with high-power operation of the PSI proton accelerator facility
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target, radiation, cyclotron, proton |
274 |
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- P. A. Schmelzbach
PSI, Villigen
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The PSI proton accelerator delivers a maximun current of 2 mA (routinely 1.9 mA) at 590 MeV. Ongoing developments aim at an upgrade of the beam current to 3 mA. This will result in an increase of the beam power from 1.2 to 1.8 MW on the pion/muon production targets and from 0.8 to 1.2 MW on the neutron spallation source SINQ. Our approach to the safe operation of a facility a these power levels will be presented. This includes considerations on the design of the cyclotrons, the beam lines and the tools to handle highly radioactive components. The protection of the facility via device controls, beam diagnostics and loss monitoring will be discussed. The specific requirements for operation with a sensitive liquid metal target like MEGAPIE will also be addressed.
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