IPAC2015 - List of Authors (Groening, L.)

Paper	Title	Page
MOPWA026	Demonstration of Flat Ion Beam Creation and Injection into a Synchrotron	153
	L. Groening, S. Appel, L.H.J. Bozyk, Y. El Hayek, M.T. Maier, C. Xiao GSI, Darmstadt, Germany
	At GSI an ion beam with different horizontal and vertical emittances has been created from a beam with initially equal emittances. This round-to-flat adoption has been accomplished without any beam loss. In the set-up the beam passes through a stripping foil placed inside a solenoid followed by a skewed quadrupole triplet. The amount of beam flatness has been controlled by setting the solenoid field strength only. Increase of the product of the two transverse emittances is purely due to the stripping process that occurs anyway along an ion linac. Beams with different amounts of flatness were injected into a synchrotron applying horizontal multi-turn injection. The efficiency of injection increased as smaller as the horizontal emittance was set by the round-to-flat adaptor.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA026
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TUXB2	Upgrade of the Unilac for Fair	1281
	L. Groening, A. Adonin, R. M. Brodhage, X. Du, R. Hollinger, O.K. Kester, S. Mickat, A. Orzhekhovskaya, B. Schlitt, G. Schreiber, H. Vormann, C. Xiao GSI, Darmstadt, Germany H. Hähnel, U. Ratzinger, A. Seibel, R. Tiede IAP, Frankfurt am Main, Germany
	The UNIversal Linear Accelerator (UNILAC) at GSI serves as injector for all ion species from protons to uranium since four decades. Its 10⁸ MHz Alvarez type DTL providing acceleration from 1.4 MeV/u to 11.4 MeV/u has suffered from material fatigue. The DTL will be replaced by a completely new section with almost same design parameters, i.e. pulsed current of up to 15 mA of 238U²⁸⁺ at 11.4 MeV/u. A dedicated terminal & LEBT for operation with 238U⁴⁺ is currently constructed. The uranium sources need to be upgraded in order to provide increased beam brilliances and for operation at 3 Hz. In parallel a 70 MeV / 70 mA proton linac based on H-mode cavities is under design and construction. This contribution will also give a brief summary of the overall status of the FAIR project.
	Slides TUXB2 [4.634 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUXB2
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TUBB2	The Accelerator Facility of the Facility for Antiproton and Ion Research	1343
	P.J. Spiller, F. Becker, A. Dolinskyy, L. Groening, O.K. Kester, K. Knie, H. Reich-Sprenger, W. Vinzenz, M. Winkler GSI, Darmstadt, Germany D. Prasuhn FZJ, Jülich, Germany
	The accelerators of the Facility for Antiproton and Ion Research – FAIR are under construction. The sophisticated system of accelerators is designed to produce stable and secondary beams with a significant variety of intensities and beam energies. FAIR will explore the intensity frontier of heavy ion accelerators and the beams for the experiments will have highest beam quality for cutting edge physics to be conducted. The main driver accelerator of FAIR will be the SIS100 synchrotron. In order to produce the intense rare isotope beams (RIB) at FAIR, a unique superconducting fragment separator is under construction. A system of storage rings will collect and cool secondary particles from the FAIR. Intense work on test infrastructure for the huge number of superconducting magnets of the FAIR machines is ongoing at GSI and several partner labs. In addition, the GSI accelerator facility is being prepared to serve as injector for the FAIR accelerators. As the construction of the FAIR accelerators and the procurement has started, an overview of the designs, procurements plans and infrastructure preparation can be provided.
	Slides TUBB2 [4.653 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUBB2
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WEPMA017	Alvarez DTL Cavity Design for the UNLAC Upgrade	2786
	X. Du, L. Groening, S. Mickat GSI, Darmstadt, Germany A. Seibel IAP, Frankfurt am Main, Germany
	The 10⁸.4 MHz drift tube linac (DTL) accelerator for GSI’s UNLAC upgrade project is in its initial design stage using CST-MWS code. Optimization criteria for cavity design are effective shunt impedance (ZTT), transit-time factor, and electrical breakdown limit. In geometrical op-timization we have aimed at increase of the energy gain in each RF gap of the DTL cells by maximizing ZTT per peak surface field with special designed tube profile. Mul-ti-pacting probability is evaluated for one gap of typical single cell. For the beta profile design, a code based on VBA macros of CST is developed to perform cell by cell design with pre-optimized 3D tube structures. With this code several beta profile designs are presented and com-pared for the balance of power consumption, ZTT, tank length, and breakdown possibility of the complete cavity. The stability of the field has been taken into account and for this the crossed stem arrangement is assessed. This paper gives a short introduction of the method, presents some important results. Possible countermeas-ures are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMA017
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THPF027	Ten Gap Model of a New Alvarez DTL Cavity at GSI	3748
	A. Seibel, O.K. Kester IAP, Frankfurt am Main, Germany X. Du, L. Groening, S. Mickat GSI, Darmstadt, Germany
	In order to meet the challenges of the FAIR project at GSI requiring highest beam intensities an upgrade of the existing Universal Linear Accelerator (UNILAC) is planned. The 10⁸ MHz cavities will be replaced by new rf-structures of the same frequency. Simulations are done to improve the rf-properties. The geometry of the drift tubes is to be changed to a smoother curvature to reach a homogeneous surface field distribution and higher shunt impedances. To check the necessity of cooling channels, simulations on the temperature distribution at the drift tubes and stems are conducted. A test bench for low power rf-measurements with a 10 gap aluminum model (scale 1:3) is under construction. The modular mechanical design of the model will allow probing experimentally a wide range of drift tube and stem geometries. With the bead pull method the electrical field distribution will be measured as well as the field stability with respect to parasitic modes. Additionally, appropriate locations along the cavity to place fixed and dynamic rf-frequency tuners will be determined.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF027
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THPF035	Stripping of High Intensity Heavy-Ion Beams in a Pulsed Gas Stripper Device at 1.4 MeV/u	3773
	P. Scharrer, W.A. Barth, Ch.E. Düllmann, J. Khuyagbaatar HIM, Mainz, Germany W.A. Barth, M. Bevcic, Ch.E. Düllmann, L. Groening, K.P. Horn, E. Jäger, J. Khuyagbaatar, J. Krier, A. Yakushev GSI, Darmstadt, Germany Ch.E. Düllmann Mainz University, Mainz, Germany
	As part of an injector system for FAIR, the GSI UNILAC has to meet high demands in terms of beam brilliance at a low duty factor. To accomplish this goal an extensive upgrade program has started. To increase the beam intensity behind the UNILAC, it is aimed to increase the efficiency of the 1.4 MeV/u gas stripper. A modification of the stripper setup was developed to replace the N2-jet with a pulsed gas injection, synchronized with the transit of the beam pulse. The pulsed gas injection lowers the gas load for the differential pumping system, rendering possible the use of other promising gas targets. In recent measurements the performance of the modified setup was tested using an 238U-beam with various stripper media, including H2, He, and N2. The data provide a systematic basis for an improved understanding of slow heavy ions passing through gaseous media. The stripping performance of the current N2-jet was excelled by using H2 at increased gas densities, enabled by the new pulsed gas cell.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF035
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Paper

Title

Page

Demonstration of Flat Ion Beam Creation and Injection into a Synchrotron

153

L. Groening, S. Appel, L.H.J. Bozyk, Y. El Hayek, M.T. Maier, C. Xiao
GSI, Darmstadt, Germany

At GSI an ion beam with different horizontal and vertical emittances has been created from a beam with initially equal emittances. This round-to-flat adoption has been accomplished without any beam loss. In the set-up the beam passes through a stripping foil placed inside a solenoid followed by a skewed quadrupole triplet. The amount of beam flatness has been controlled by setting the solenoid field strength only. Increase of the product of the two transverse emittances is purely due to the stripping process that occurs anyway along an ion linac. Beams with different amounts of flatness were injected into a synchrotron applying horizontal multi-turn injection. The efficiency of injection increased as smaller as the horizontal emittance was set by the round-to-flat adaptor.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUXB2

Upgrade of the Unilac for Fair

1281

L. Groening, A. Adonin, R. M. Brodhage, X. Du, R. Hollinger, O.K. Kester, S. Mickat, A. Orzhekhovskaya, B. Schlitt, G. Schreiber, H. Vormann, C. Xiao
GSI, Darmstadt, Germany
H. Hähnel, U. Ratzinger, A. Seibel, R. Tiede
IAP, Frankfurt am Main, Germany

The UNIversal Linear Accelerator (UNILAC) at GSI serves as injector for all ion species from protons to uranium since four decades. Its 10⁸ MHz Alvarez type DTL providing acceleration from 1.4 MeV/u to 11.4 MeV/u has suffered from material fatigue. The DTL will be replaced by a completely new section with almost same design parameters, i.e. pulsed current of up to 15 mA of 238U²⁸⁺ at 11.4 MeV/u. A dedicated terminal & LEBT for operation with 238U⁴⁺ is currently constructed. The uranium sources need to be upgraded in order to provide increased beam brilliances and for operation at 3 Hz. In parallel a 70 MeV / 70 mA proton linac based on H-mode cavities is under design and construction. This contribution will also give a brief summary of the overall status of the FAIR project.

Slides TUXB2 [4.634 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUXB2

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUBB2

The Accelerator Facility of the Facility for Antiproton and Ion Research

1343

P.J. Spiller, F. Becker, A. Dolinskyy, L. Groening, O.K. Kester, K. Knie, H. Reich-Sprenger, W. Vinzenz, M. Winkler
GSI, Darmstadt, Germany
D. Prasuhn
FZJ, Jülich, Germany

The accelerators of the Facility for Antiproton and Ion Research – FAIR are under construction. The sophisticated system of accelerators is designed to produce stable and secondary beams with a significant variety of intensities and beam energies. FAIR will explore the intensity frontier of heavy ion accelerators and the beams for the experiments will have highest beam quality for cutting edge physics to be conducted. The main driver accelerator of FAIR will be the SIS100 synchrotron. In order to produce the intense rare isotope beams (RIB) at FAIR, a unique superconducting fragment separator is under construction. A system of storage rings will collect and cool secondary particles from the FAIR. Intense work on test infrastructure for the huge number of superconducting magnets of the FAIR machines is ongoing at GSI and several partner labs. In addition, the GSI accelerator facility is being prepared to serve as injector for the FAIR accelerators. As the construction of the FAIR accelerators and the procurement has started, an overview of the designs, procurements plans and infrastructure preparation can be provided.

Slides TUBB2 [4.653 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUBB2

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMA017

Alvarez DTL Cavity Design for the UNLAC Upgrade

2786

X. Du, L. Groening, S. Mickat
GSI, Darmstadt, Germany
A. Seibel
IAP, Frankfurt am Main, Germany

The 10⁸.4 MHz drift tube linac (DTL) accelerator for GSI’s UNLAC upgrade project is in its initial design stage using CST-MWS code. Optimization criteria for cavity design are effective shunt impedance (ZTT), transit-time factor, and electrical breakdown limit. In geometrical op-timization we have aimed at increase of the energy gain in each RF gap of the DTL cells by maximizing ZTT per peak surface field with special designed tube profile. Mul-ti-pacting probability is evaluated for one gap of typical single cell. For the beta profile design, a code based on VBA macros of CST is developed to perform cell by cell design with pre-optimized 3D tube structures. With this code several beta profile designs are presented and com-pared for the balance of power consumption, ZTT, tank length, and breakdown possibility of the complete cavity. The stability of the field has been taken into account and for this the crossed stem arrangement is assessed. This paper gives a short introduction of the method, presents some important results. Possible countermeas-ures are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMA017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPF027

Ten Gap Model of a New Alvarez DTL Cavity at GSI

3748

A. Seibel, O.K. Kester
IAP, Frankfurt am Main, Germany
X. Du, L. Groening, S. Mickat
GSI, Darmstadt, Germany

In order to meet the challenges of the FAIR project at GSI requiring highest beam intensities an upgrade of the existing Universal Linear Accelerator (UNILAC) is planned. The 10⁸ MHz cavities will be replaced by new rf-structures of the same frequency. Simulations are done to improve the rf-properties. The geometry of the drift tubes is to be changed to a smoother curvature to reach a homogeneous surface field distribution and higher shunt impedances. To check the necessity of cooling channels, simulations on the temperature distribution at the drift tubes and stems are conducted. A test bench for low power rf-measurements with a 10 gap aluminum model (scale 1:3) is under construction. The modular mechanical design of the model will allow probing experimentally a wide range of drift tube and stem geometries. With the bead pull method the electrical field distribution will be measured as well as the field stability with respect to parasitic modes. Additionally, appropriate locations along the cavity to place fixed and dynamic rf-frequency tuners will be determined.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPF035

Stripping of High Intensity Heavy-Ion Beams in a Pulsed Gas Stripper Device at 1.4 MeV/u

3773

P. Scharrer, W.A. Barth, Ch.E. Düllmann, J. Khuyagbaatar
HIM, Mainz, Germany
W.A. Barth, M. Bevcic, Ch.E. Düllmann, L. Groening, K.P. Horn, E. Jäger, J. Khuyagbaatar, J. Krier, A. Yakushev
GSI, Darmstadt, Germany
Ch.E. Düllmann
Mainz University, Mainz, Germany

As part of an injector system for FAIR, the GSI UNILAC has to meet high demands in terms of beam brilliance at a low duty factor. To accomplish this goal an extensive upgrade program has started. To increase the beam intensity behind the UNILAC, it is aimed to increase the efficiency of the 1.4 MeV/u gas stripper. A modification of the stripper setup was developed to replace the N2-jet with a pulsed gas injection, synchronized with the transit of the beam pulse. The pulsed gas injection lowers the gas load for the differential pumping system, rendering possible the use of other promising gas targets. In recent measurements the performance of the modified setup was tested using an 238U-beam with various stripper media, including H2, He, and N2. The data provide a systematic basis for an improved understanding of slow heavy ions passing through gaseous media. The stripping performance of the current N2-jet was excelled by using H2 at increased gas densities, enabled by the new pulsed gas cell.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)