Author: Ratzinger, U.
Paper Title Page
THPP094 The Heavy Ion Injector at the NICA Project 1068
THPOL04   use link to see paper's listing under its alternate paper code  
 
  • A.V. Butenko, D.E. Donets, E.E. Donets, A.D. Kovalenko, A.O. Sidorin, A. Tuzikov
    JINR/VBLHEP, Dubna, Moscow region, Russia
  • V. Aleksandrov, E.D. Donets, A. Govorov, V. Kobets, K.A. Levterov, I.N. Meshkov, V.A. Mikhaylov, V. Monchinsky, G.V. Trubnikov
    JINR, Dubna, Moscow Region, Russia
  • H. Hoeltermann, H. Podlech, U. Ratzinger, A. Schempp
    BEVATECH, Frankfurt, Germany
  • T. Kulevoy, D.A. Liakin
    ITEP, Moscow, Russia
  
  The general goals of the Nuclotron-based Ion Collider fAcility (NICA) project at JINR (Dubna) are providing of colliding beams for experimental studies of both hot and dense strongly interacting baryonic matter and spin physics. The experiments will be performed in collider mode and at fixed target. The first part of the project program requires the collisions of heavy nuclei up to 197Au79+ to be studied. The new heavy ion linac – HILac (Heavy Ion Linear Accelerator) will accelerate ions with q/A – values above 0.16 to 3.2 MeV/u is under manufacturing presently. The main features of HILac are described.  
 
MOPP060 Status of the GSI Poststripper - HE-Linac 190
 
  • S. Mickat, W.A. Barth, G. Clemente, X. Du, L. Groening, A. Orzhekhovskaya, B. Schlitt, H. Vormann, C. Xiao, S.G. Yaramyshev
    GSI, Darmstadt, Germany
  • M. Droba, H. Hähnel, U. Ratzinger, R. Tiede
    IAP, Frankfurt am Main, Germany
  
  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.  
 
MOPP061 First RF Measurements of the Superconducting 217 MHz CH Cavity for the CW Demonstrator at GSI 193
 
  • F.D. Dziuba, M. Amberg, M. Basten, M. Busch, H. Podlech, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  • M. Amberg, K. Aulenbacher, W.A. Barth, S. Mickat
    HIM, Mainz, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
  • W.A. Barth, S. Mickat
    GSI, Darmstadt, Germany
  
  Funding: Work supported by GSI, HIM, BMBF Contr. No. 05P12RFRBL
Presently, a superconducting (sc) 217 MHz Crossbar-Hmode (CH) cavity is under construction at Research Instruments (RI), Bergisch Gladbach, Germany. Among the horizontal cryomodule and two sc 9.5 T solenoids the cavity is the key component of the cw demonstrator at GSI. To show the operation ability of sc CH cavity technology under a realistic linear accelerator environment is one major goal of the demonstrator project. A successful beam operation of the demonstrator will be a milestone regarding the continuing advanced sc cw linac project at GSI for a competitive production of Super Heavy Elements (SHE) in the future. The fabrication status as well as first rf measurements at room temperature of the 217 MHz CH cavity are presented. 		 
poster icon Poster MOPP061 [1.741 MB]  
 
MOPP062 Proposal of a Conventional Matching Section as an Alternative to the Existing HSI MEBT Superlens at GSI UNILAC 196
 
  • H. Hähnel, U. Ratzinger, R. Tiede
    IAP, Frankfurt am Main, Germany
  
  We propose a new design for the HSI MEBT section at GSI UNILAC as part of the planned UNILAC upgrade. The existing MEBT section was designed in 1996 and based on a novel concept called the superlens* which uses a magnetic quadrupol doublet lens combined with a short RFQ cavity for transversal and longitudinal focusing. In 2009 the RFQ section in front of the MEBT was upgraded which led to significant changes in the RFQ output particle distribution. Recent LORASR simulations show that the superlens transmission decreases to 90% (related to 20.75 mA, U4+ at input). Moreover, the matching to the following IH-DTL is not ideal. This leads to further losses in the IH and to a decrease of the overall UNILAC efficiency. To reach the FAIR requirement of 18 mA U4+ current for the UNILAC with minimal losses and to provide more flexibility for varying current level operation, a new design based on two magnetic quadrupole triplet lenses and a 2-gap buncher is proposed. The design shows full transmission at 20.75 mA U4+ current and improved matching to the IH-DTL, leading to a drastic decrease of particle losses along the IH-DTL.
* U. Ratzinger, R. Tiede, A New Matcher Type between RFQ and IH-DTL for the GSI High Current Heavy Ion Prestripper LINAC, Proc. LINAC96, Geneva, Switzerland, pp. 128-130 		 
poster icon Poster MOPP062 [9.440 MB]  
 
MOPP063 Development of a Pepper Pot Emittance Measurement Device for FRANZ 199
 
  • B. Klump, U. Ratzinger, W. Schweizer, K. Volk
    IAP, Frankfurt am Main, Germany
  
  Funding: This work is supported by HGS-HIRe
Within the FRANZ project [*] on the Institute of Applied Physics, University Frankfurt, a robust and simple pepper pot emittance measurement device for high beam power densities is developed. To use the device directly behind the ion source, a high robustness against HV breakdowns is necessary. This paper gives an overview on experimental setup, on the analysis method and on imaging properties of the screen. Furthermore, the implemented software-based evaluation method is shown. It concludes with a preliminary emittance measurement on the high current ion source for FRANZ.
[*] U. Ratzinger et al., “intense Pulsed Neutron Source FRANZ in the 1-500 keV Range“, Proc. ICANS-XVIII, Dongguan, April 2007, p.210
 		 
 
MOPP065 Investigations of Space-Charge Compensation in Low-Energy Beam Transport (LEBT) Sections Using a Particle-in-Cell Code 205
 
  • D. Noll, M. Droba, O. Meusel, U. Ratzinger, K. Schulte, C. Wiesner
    IAP, Frankfurt am Main, Germany
  
  Among the advantages of magnetostatic LEBT sections is the possibility for compensation of space charge by electrons in the case of positively charged ion beams. In the past, it has been shown that the distribution of these compensation electrons can lead to unwanted emittance growth. However, the distribution of electrons especially in the presence of the magnetic fields of the focussing lenses is difficult to predict. To improve the understanding of the influence on the beam, models for the relevant processes namely residual gas ionization using realistic cross sections as well as secondary electron production on surfaces have been implemented in a particle-in-cell code. In this contribution, we will present the code used as well as first results for two model systems as an example.  
 
MOPP066 High Gradient CH-Type Cavity Development for 10 – 100 AMeV Beams 208
 
  • A. Almomani, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  
  Funding: This work is supported by Federal Ministry of Education and Research - BMBF No. 05P12RFRB9.
The development in pulsed linac activities aims on compact designs and on an increase of the voltage gain per meter. At IAP - Frankfurt, a CH design was developed for these studies, where the mean effective accelerating field is expected to reach well above 10 MV/m at 325 MHz, β=0.164. Within a funded project, this cavity is systematically developed. Currently, the cavity is under construction at NTG GmbH and expected to be ready for copper plating in autumn 2014. The results should give an impact on the rebuilt of the UNILAC - Alvarez section, optimized for achieving the beam intensities specified for the GSI – FAIR project. A mid- and long- term aim is a compact pulsed high current linac. The new GSI 3 MW Thales klystron test stand will be very important for these investigations. Detailed studies on two different types of copper plating can be performed on this cavity. Additionally, operating of normal conducting cavities at cryogenic temperatures will be discussed. In this work, the cavity status will be presented. 		 
 
MOPP068 The Fast Piezo-Based Frequency Tuner for SC CH-Cavities 214
 
  • M. Amberg, M. Busch, F.D. Dziuba, H. Podlech, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  • K. Aulenbacher
    HIM, Mainz, Germany
  • W.A. Barth, V. Gettmann, S. Mickat
    GSI, Darmstadt, Germany
  
  Funding: Work supported by HIM, GSI, BMBF Contr. No 05P12RFRBL
Superconducting structures are very susceptible to external influences due to their thin walls and their narrow bandwidth. Even small mechanical deformations caused by dynamic effects like microphonic noise, pressure fluctuations of the liquid helium bath or Lorentz-Force-Detuning can lead to resonance frequency changes of the cavity which are much larger than the bandwidth. To compensate the slow and fast resonance frequency variations during operation a compact frequency tuner prototype equipped with a stepper motor and a piezo actuator has been developed at the Institute for Applied Physics (IAP) of Frankfurt University. In this paper, the tuner design and the results of first room temperature measurements of the tuner prototype are presented. 		 
poster icon Poster MOPP068 [2.304 MB]  
 
TUPP062 A Rebunching CH Cavity for Intense Proton Beams 566
SUPG011   use link to see paper's listing under its alternate paper code  
 
  • M. Schwarz, C. Claessens, M. Heilmann, O. Hinrichs, D. Koser, O. Meusel, D. Mäder, H. Podlech, U. Ratzinger, A. Seibel
    IAP, Frankfurt am Main, Germany
  
  Funding: Project supported by the EU, FP7 MAX, Contract No. 269565
The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) will provide ultra short neutron pulses at high intensities and repetition rates. The facility is currently under construction at the Goethe-University in Frankfurt am Main (Germany). A 5-Gap CH rebuncher is installed behind a coupled RFQ/IH-DTL combination at the end of the LINAC section between two magnetic quadrupole triplets. It will be used for varying the final proton energy as well as for focusing the bunch longitudinally to compensate huge space charge forces at currents up to 200 mA at the final stage of extension. High current beam dynamic simulations have been performed. They include benchmarking of different beam dynamic codes like LORASR and TraceWin, as well as validating the results by measurements. Detailed examination of multipole field impact, due to the cavity’s geometry, together with error tolerance studies and thermal simulations are also performed. Furthermore, this CH rebuncher serves as a prototype for rt CH cavities at MYRRHA (Belgium), an Accelerator Driven System for transmutation of high level nuclear waste. After copper plating the cavity, RF conditioning will start soon. 		 
poster icon Poster TUPP062 [6.015 MB]  
 
TUPP063 Improvements of the LORASR Code and their Impact on Current Beam Dynamics Designs 569
 
  • R. Tiede, D. Mäder, N.F. Petry, H. Podlech, U. Ratzinger, C. Zhang
    IAP, Frankfurt am Main, Germany
  
  LORASR is a multi-particle tracking code optimized for the beam dynamics design of ‘Combined Zero Degree Structure (KONUS)’ lattices, which can benefit from an adapted input file structure and code architecture. Recent code developments focused on the implementation of tools for machine error studies and loss profile investigations, including also steering correction strategies. These tools are a stringent necessity for the design of high intensity linacs. Thus, the abilities of the present LORASR release allow performing a manifold of checks and optimizations before finalizing the layouts of KONUS-based or conventional linacs. Two representative examples are the MAX-MYRRHA Injector and the GSI FAIR Facility Proton Linac, both under development with strong participation of IAP, Frankfurt University. This paper presents the status of the LORASR code development with focus on the new features and illustrates the impact on current designs by examples taken from the above-mentioned projects.  
 
WEIOB01 Chopping High-Intensity Ion Beams at FRANZ 765
 
  • C. Wiesner, M. Droba, O. Meusel, D. Noll, O. Payir, U. Ratzinger, P.P. Schneider
    IAP, Frankfurt am Main, Germany
  
  The accelerator-driven Frankfurt Neutron Source FRANZ is under construction at the science campus of Frankfurt University. Its Low-Energy Beam Transport (LEBT) line also serves as test stand for transport and chopping experiments with high-intensity ion beams. The high-current proton source was tested successfully with dc currents above 200 mA . The LEBT section consisting of four solenoids and a 250 kHz, 120 ns chopper was successfully commissioned using a helium test beam at low beam currents. Transport simulations including space-charge compensation and measurements are discussed. Simulations and experimental results of the novel LEBT chopper using a Wien-filter type field array and pulsed electrode voltages of up to ±6kV will be presented.  
slides icon Slides WEIOB01 [7.925 MB]  
 
THPP064
 First CH Power Cavity for the FAIR Proton Injector  
 
  • R. M. Brodhage, G. Clemente, W. Vinzenz
    GSI, Darmstadt, Germany
  • U. Ratzinger
    IAP, Frankfurt am Main, Germany
  
  For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. The main acceleration of this room temperature linac will be provided by six CH cavities operated at 325 MHz. Each cavity will be powered by a 2.5 MW Klystron. For the second acceleration unit from 11.5 MeV to 24.2 MeV a 1:2 scaled model has been built. Low level RF measurements have been performed to determine the main parameters and to prove the concept of coupled CH cavities. In 2012, the assembly and tuning of the first power prototype was finished. Until then, the cavity was tested with a preliminary aluminum drift tube structure, which was used for precise frequency and field tuning. In 2013 the final drift tube structure has been welded inside the main tanks and the preparation for copper plating has taken place. This paper will report on the main tuning and commissioning steps towards that novel type of DTL and it will show the latest results measured on a fully operational and copper plated CH proton cavity.  
 
THPP068 Cold Power Tests of the SC 325 MHz CH-Cavity 1007
SUPG012   use link to see paper's listing under its alternate paper code  
 
  • M. Busch, M. Amberg, F.D. Dziuba, H. Podlech, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  • M. Amberg
    HIM, Mainz, Germany
  
  Funding: Work supported by GSI, BMBF Contr. No. 06FY7102
At the Institute for Applied Physics (IAP), Frankfurt University, a superconducting 325 MHz CH-Cavity has been designed, built and first tests have successfully been performed. The cavity is determined for a 11.4 AMeV, 10 mA ion beam at the GSI UNILAC. Consisting of 7 gaps this resonator is envisaged to deliver a gradient of 5 MV/m. Novel features of this structure are a compact design, low peak fields, improved surface processing and power coupling. Furthermore a tuner system based on bellow tuners driven by a stepping motor and a piezo actuator and attached inside the resonator will control the frequency. In this contribution measurements executed at 4 K and 2 K at the cryo lab in Frankfurt will be presented. 		 
poster icon Poster THPP068 [1.449 MB]  
 
THPP070 Alternative Compact LEBT Design for the FAIR Injector Upgrade 1013
 
  • K. Schulte, M. Droba, S. Klaproth, O. Meusel, D. Noll, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  • S.G. Yaramyshev
    GSI, Darmstadt, Germany
  
  In order to provide high intensity and brightness of the uranium beam for the planned FAIR project, the existing High Current Injector (HSI) at GSI has to be upgraded*. A part of the upgrade program is the design and construction of a compact straight injection line into the 36 MHz Radio Frequency Quadrupole of the HSI. As an alternative to a conventional LEBT design consisting of magnetic systems such as solenoids or quadrupoles, the application of Gabor lenses has been investigated. The focusing force of the Gabor lens is created by the space charge of an electron cloud, confined by crossed magnetic and electric fields inside the lens volume. Therefore, the Gabor lens combines strong, electrostatic focusing with simultaneous space-charge compensation. In previously performed beam transport experiments at GSI a prototype Gabor lens has been tested successfully. Furthermore, the operation and performance of such a device in a real accelerator environment has been studied. In this contribution an alternative LEBT design will be discussed and an improved Gabor lens design will be presented.
*W. Barth et al., “HSI-Frontend Upgrade”, GSI Scientific Report, 2009 		 
 
THPP071 Proposal of a 325 MHz Ladder-RFQ for the FAIR Proton-Linac 1016
 
  • M. Schütt, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  • R. M. Brodhage
    GSI, Darmstadt, Germany
  
  Funding: BMBF 05P12RFRB9
For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. The first rf accelerator element is a 325 MHz RFQ accelerating from 95 keV to 3.0 MeV. RFQ’s beyond 300 MHz were realized in 4-Vane-type geometry so far. At IAP there is a tradition in 4-Rod-type RFQ development. This type of RFQ is dominating at lower frequencies. Very promising results have been reached with a ladder type-RFQ, which has been investigated during 2013. In comparison with a traditional 4-Rod RFQ approach the geometry is more convenient at high frequencies. We will show most recent 3D simulations of the frequency tuning possibilities and of a whole cavity demonstrating the power of a ladder type RFQ. An RFQ layout for the new FAIR proton injector will be shown. (see also R. Brodhage, U. Ratzinger, A. Almomani, “Design Study of a High Frequency Proton Ladder RFQ” , Proc. of the 2013 IPAC Conference, Shanghai, China, p. 3788.)