| Paper | Title | Page |
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| MOIOC02 | Single-Knob Beam Line for Transverse Emittance Partitioning | 36 |
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| Flat beams feature unequal emittances in the horizontal and vertical phase space. Such beams were created successfully in electron machines by applying effective stand-alone solenoid fringe fields in the electron gun. Extension of this method to ion beams was proposed conceptually. The present paper is on the decoupling capabilities of an ion beam emittance transfer line. The proposed beam line provides a single-knob tool to partition the horizontal and vertical rms emittances, while keeping the product of the two emittances constant as well as the transverse rms Twiss parameters (αx,y and βx,y) in both planes. It is shown that this single knob is the solenoid field strength, and now we fully understand the decoupling features. | ||
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Slides MOIOC02 [1.327 MB] | |
| MOPP060 | Status of the GSI Poststripper - HE-Linac | 190 |
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| The High-Energy (HE) Linac is proposed to substitute the existing UNILAC post-stripper section. The post-stripper is an Alvarez DTL, which is in operation over four decades successfully. A quasi Front-to-End simulation along the UNILAC shows, that by taking future upgrade options into account already, with the existing Alvarez section the Fair requirements are not reached. Even by substituting the Alvarez section by the HE Linac the aim is not reached per se regarding the existing boundary conditions. Currently workpackages are defined together with the Institute of Applied Physics at Frankfurt University. Starting from the Ion sources to the SIS18 transfer channel every section is reinvestigated for improvements in beam quality and intensity. | ||
| TUPP057 | In Situ Measurement of Mechanical Vibrations of a 4-Rod RFQ at GSI | 553 |
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A new 4-rod CW Radio Frequency Quadrupole was commissioned at the high charge state injector HLI at the UNILAC in 2009. It is in operation since 2010*. At high rf amplitudes strong modulations of the rf reflection emerge, with a modulation frequency of approximately 500 Hz. They are attributed to mechanical oscillations of the rods, excited by the rf pulse. The high fraction of reflected rf power severely limits the pulse length and rf amplitude achievable. As these modulations could only be seen during the rf pulse by means of rf measurements, a direct observation of the mechanical vibrations was desirable. Such measurements have been conducted using a commercial laser vibrometer, allowing for the investigation of the mechanical behavior of the RFQ independent of the presence of rf power. After a short introduction of the method, the results will be presented and compared with rf measurements and simulations.
*: P. Gerhard et al., “Experience with a 4–Rod CW RFQ”, LINAC’12, Sept. 2012, Tel Aviv, THPB035 |
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| TUPP059 | Advanced Beam Matching to a High Current RFQ | 559 |
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| The High Current Injector (HSI) of the heavy ion linac UNILAC at GSI comprises the transport lines, the RFQ and two DTL tanks. Beam matching to the RFQ acceptance with a magnetic quadrupole quartet has been worked out manually during commissioning and operation of the machine. Due to a strong overlapping of the field from neighboring quadrupole lenses, a standard optics calculation does not provide for the required reliability. Advanced beam dynamics simulations have been done with the macroparticle code DYNAMION. The superposition of the measured magnetic fields of each quadrupole was taken into account. The quadrupole settings were optimized using the Monte-Carlo method. Two solutions have been found in accordance with the general theory of particle optics. Beam dynamics simulations with new quadrupole settings show an increased particle transmission through the RFQ. The results of numerical study have been confirmed during experimental campaigns. An improved performance of the whole HSI has been demonstrated. The proposed algorithm and a comparison of the measured data with result of simulations are presented. | ||
| THPP065 | Acceleration of Intense Flat Beams in Periodic Lattices | 1001 |
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| Recently a scheme for creation of flat ion beams from linacs has been proposed to increase the efficiency of multi-turn-injection. The proof of principle experiment shall be performed at GSI in Summer 2014. Since the scheme requires charge stripping, it may be necessary to perform the round-to-flat transformation prior to acceleration to the final energy of the linac. This requires preservation of the beam flatness during acceleration along the drift tube linac. This contribution is on simulations of acceleration of flat beams subject to considerable space charge tune depression. It is shown that the flatness can be preserved if the transverse tunes are properly chosen and if mis-match along inter-tank sections is minimized along the DTL. | ||