| Paper | Title | Page |
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| MOPPD050 | Dipole Magnet Design for a Bunch Compressor | 478 |
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| The FRANZ-ARMADILLO is a Mobley type bunch compressor system at the pulsed intense neutron source FRANZ, under construction at Frankfurt University. The FRANZ-ARMADILLO compresses 9μbunches of a 150 mA, 2 MeV proton beam accelerated by a 175 MHz linac into one short pulse of 1 ns pulse length with 250 kHz repetition rate. In the bunch compressor, two homogeneous dipole magnets and two gradient dipole magnets guide theμbunches, separated by a 5 MHz RF-kicker on individual tracks. The flight path length of theμbunches are determined based on the bunch center velocity and the linac frequency for the longitudinal bunch compression. The gradient dipole magnets provide individual magnetic fields and edge focusing forces to everyμbunch. For the center trajectory, the required parameters are a magnetic field density of 509.2 mT, bending angle of 78.27 deg, and bending radius of 404.5 mm. To satisfy all specifications, field clamps, shims, and chamfer cut will be adopted. The result of the gradient dipole magnet design and the expected performance based on beam dynamics studies will be presented. | ||
| TUPPC007 | Electron Cloud Dynamics in a Gabor Space Charge Lens | 1164 |
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| Inside Gabor space charge lenses, external fields confine electrons forming a homogeneously distributed electron cloud. Its linear electric space charge field enables the focusing of high intensity heavy ion beams without aberrations. The focusing performance depends on the properties of the non-neutral plasma. In a small-scale table top experiment, different types of space charge lenses are used to characterize the collective behavior of the confined electron cloud using new non-interceptive diagnostic methods. The plasma parameters, e.g. electron temperature and density, are important to an improved understanding of loss and production mechanisms as well as the electron cloud dynamics. In this context, the evolution of instabilities caused by the enclosing fields has been investigated in detail. Experimental results will be presented and compared to numerical simulations. | ||
| WEPPD031 | A Transverse Electron Target for Heavy Ion Storage Rings | 2573 |
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Funding: supported by HIC for FAIR A transverse electron target is a well suited concept for storage rings to investigate electron-ion interactions processes relevant for heavy ion accelerators. In comparison with an internal gas target, it promises a better energy resolution but still has the advantage, in contrast to an electron cooler, of access to the interaction region for photon and electron spectroscopy under large solid angles. The new electron target is suited for the use under the UHV requirements of a storage ring and realizes an open geometry for spectroscopy. A simple design based on electrostatic fields was chosen. The sheet beam application provides a higher perveance limit and a smaller potential depression than a cylindrical gun arrangement. The adjustable electron energy ranges between several 10eV and a few keV. The setup will be installed applying the so-called animated beam technique. The electron target is dedicated to the NESR at the new FAIR facility. First measurements are planned at a test bench and subsequent tests at the Frankfurt Low Energy Storage Ring (FLSR) are envisaged. An overview of the progress in the development of the transverse electron target will be given. |
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| WEPPP016 | De-neutralization of Laser Produced Proton Pulse in a Strong Solenoidal Magnetic Field | 2755 |
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| Laser generated proton pulses of ten to several ten MeV produced in PHELIX-laser facility at GSI Darmstadt poses some unique characteristics. The first systematic exploration of the interface between proton pulse generation via the TNSA mechanism and conventional accelerator technology is within the scope of the LIGHT (Laser Ion Generation, Handling and Transport) project. One of the main tasks is to study the beam dynamics in intense B-fields, especially in context of early de-neutralization and space charge effects. The 3D numerical simulations with co-moving electrons and up to 107 macroparticles were performed to investigate the de-neutralization process in the focusing magnetic solenoid. Importance of the first focusing element and influence on beam parameters will be addressed. Results of the 3D simulation model will be presented and discussed. | ||
| THPPP074 | Chopping High Intensity Proton Beams Using a Pulsed Wien Filter | 3907 |
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Chopping high intensity beams at low energies poses substantial challenges. A novel ExB chopper system for proton beams of up to 200 mA at energies of 120 keV is being developed for the accelerator driven neutron source FRANZ*. It uses a Wien filter-type ExB configuration consisting of a static magnetic deflection field and a pulsed electric compensation field to deliver 100 ns beam pulses. The setup minimizes the risk of voltage breakdowns and provides secure beam dumping outside the transport line. In order to prevent beam aberrations and emittance growth careful matching of electric and magnetic deflection forces is required. Detailed numerical studies for the field design and their effects on beam transport were conducted. An H-type dipole magnet with special transverse and longitudinal pole contours was manufactured and combined with shielding tubes to shape the magnetic field. The electric field is driven by a HV pulse generator providing ±6 kV at a repetition rate of 250 kHz. Accurate layout of the deflector plates is required in order to tackle the issues of field quality, cooling and spark prevention. Transport simulations and beam deflection experiments are presented.
* U. Ratzinger et al., "The Driver Linac of the Neutron Source FRANZ," Proc. of IPAC2011, WEPS040, P. 2577 (2011). |
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