IPAC2013 - List of Authors (Meusel, O.)

Paper	Title	Page
MOPEA015	A Transverse Electron Target for Heavy Ion Storage Rings	97
	S. Geyer, O. Meusel, D. Ries IAP, Frankfurt am Main, Germany O.K. Kester GSI, Darmstadt, Germany
	A transverse electron target is a well suited concept under discussion for storage rings to investigate electron-ion interaction processes relevant for heavy ion accelerators. Using a sheet beam of free electrons in crossed beam geometry promises not only a high energy resolution but also allows access to the interaction region for photon and electron spectroscopy under large solid angles. To realize a compact and multi-purpose applicable design, only electrostatic fields are used for beam focussing. The produced electron beam has a length of 10cm in ion beam direction and a width of around 5mm in the interaction region with densities of ~10⁹electrons/cm³. The target geometry allows the independent adjustment of the electron beam current and energy in the region of several 10eV and a few keV. The setup meets the high requirements for an operation in the UHV environment of a storage ring and is installed applying the so-called animated beam technique. The electron target is dedicated to the FAIR storage rings. First measurements have been performed at a test bench. An overview of the project status will be presented including first results of the characterization measurements.

TUPWO008	High-Current Beam Transport Simulations Including Gabor Lenses in Varying Non-Neutral Plasma States	1892
	M. Droba, H. Dinter, O. Meusel, D. Noll, U. Ratzinger, K. Schulte IAP, Frankfurt am Main, Germany
	The Gabor space charge lens has theoretically and experimentally been investigated at IAP for many years. Especially the application in high current, Low Energy Beam Transport (LEBT) sections seems efficient and attractive. The focusing properties and imaging quality of this lens type depend on the transverse and longitudinal confinement of the electron column. Different non-neutral plasma states have been observed and calculated. In general, they can be disturbed by the interaction with ion beams. This results in a shift and in a modification of the work function with a rise of aberrations and beam emittance growth. It is necessary to understand such processes for transport channels using intense ion beams to preserve the high beam brilliance. The beam transport simulations including Gabor lenses in various non-neutral plasma states will be presented and compared with experimental results.

THPWO017	A Coupled RFQ-IH Cavity for the Neutron Source FRANZ	3797
	M. Heilmann, C. Claessens, O. Meusel, D. Mäder, U. Ratzinger, A. Schempp, M. Schwarz IAP, Frankfurt am Main, Germany
	The Frankfurt neutron Source at the Stern-Gerlach-Zentrum (FRANZ) delivers neutrons in the energy range from 1 to 300 keV at high intensities. The neutrons are produced using the the 7Li(p,n)7Be reaction with 2 MeV protons. The linac accelerator cavities consists of a 4-rod-RFQ coupled with an 8 gap interdigital H-type drift tube section with a total cavity length of 2.3 m. It accelerates the 120 keV beam to 2.03 MeV at a frequency of 175 MHz. The combined cavity will be powered by one RF amplifier to reduce investment and operation costs. The inductive power coupler will be located at the RFQ part. The coupling into the IH – section is provided by direct inductive coupling within the cavity. The coupled RFQ-IH combination is investigated with CST-MWS-simulations and by an RF model. The linac combination has to match the resonance frequency, flatness along the RFQ and the voltage ratio between both cavity sections. Beam operation will be cw (a few mA) and pulsed 250 kHz, 50 ns (up to 50 mA and beyond). The thermal cavity losses are about 200 kW and the cooling is the challenging topic.

THPWO021	Gabor Lens Performance Studies at the GSI High Current Test Injector	3806
	K. Schulte, M. Droba, O. Meusel, U. Ratzinger IAP, Frankfurt am Main, Germany A. Adonin, R. Berezov, R. Hollinger, J. Pfister GSI, Darmstadt, Germany
	At the Institute for Applied Physics (IAP) the application of Gabor space charge lenses as a focusing device for low energy ion beams has already been studied for several years. Inside Gabor lenses electrons are confined by external fields. In case of a homogeneously distributed electron cloud the resulting linear electric space charge field enables the focusing of high intensity heavy ion beams without aberrations. Therefore, the Gabor lens is a promising approach for mass-independent focusing and possible space charge compensation of ion beams. In mid-2012 the performance of a prototype lens has successfully been tested at the GSI High Current Test Injector (HOSTI). GSI and IAP are currently investigating the possible application of such a device for the continuous operation at the High Current Injector (HSI) for FAIR. This contribution will present the results of beam transport experiments at HOSTI as well as the determination of related plasma properties.

Paper

Title

Page

A Transverse Electron Target for Heavy Ion Storage Rings

97

S. Geyer, O. Meusel, D. Ries
IAP, Frankfurt am Main, Germany
O.K. Kester
GSI, Darmstadt, Germany

A transverse electron target is a well suited concept under discussion for storage rings to investigate electron-ion interaction processes relevant for heavy ion accelerators. Using a sheet beam of free electrons in crossed beam geometry promises not only a high energy resolution but also allows access to the interaction region for photon and electron spectroscopy under large solid angles. To realize a compact and multi-purpose applicable design, only electrostatic fields are used for beam focussing. The produced electron beam has a length of 10cm in ion beam direction and a width of around 5mm in the interaction region with densities of ~10⁹electrons/cm³. The target geometry allows the independent adjustment of the electron beam current and energy in the region of several 10eV and a few keV. The setup meets the high requirements for an operation in the UHV environment of a storage ring and is installed applying the so-called animated beam technique. The electron target is dedicated to the FAIR storage rings. First measurements have been performed at a test bench. An overview of the project status will be presented including first results of the characterization measurements.

TUPWO008

High-Current Beam Transport Simulations Including Gabor Lenses in Varying Non-Neutral Plasma States

1892

M. Droba, H. Dinter, O. Meusel, D. Noll, U. Ratzinger, K. Schulte
IAP, Frankfurt am Main, Germany

The Gabor space charge lens has theoretically and experimentally been investigated at IAP for many years. Especially the application in high current, Low Energy Beam Transport (LEBT) sections seems efficient and attractive. The focusing properties and imaging quality of this lens type depend on the transverse and longitudinal confinement of the electron column. Different non-neutral plasma states have been observed and calculated. In general, they can be disturbed by the interaction with ion beams. This results in a shift and in a modification of the work function with a rise of aberrations and beam emittance growth. It is necessary to understand such processes for transport channels using intense ion beams to preserve the high beam brilliance. The beam transport simulations including Gabor lenses in various non-neutral plasma states will be presented and compared with experimental results.

THPWO017

A Coupled RFQ-IH Cavity for the Neutron Source FRANZ

3797

M. Heilmann, C. Claessens, O. Meusel, D. Mäder, U. Ratzinger, A. Schempp, M. Schwarz
IAP, Frankfurt am Main, Germany

The Frankfurt neutron Source at the Stern-Gerlach-Zentrum (FRANZ) delivers neutrons in the energy range from 1 to 300 keV at high intensities. The neutrons are produced using the the 7Li(p,n)7Be reaction with 2 MeV protons. The linac accelerator cavities consists of a 4-rod-RFQ coupled with an 8 gap interdigital H-type drift tube section with a total cavity length of 2.3 m. It accelerates the 120 keV beam to 2.03 MeV at a frequency of 175 MHz. The combined cavity will be powered by one RF amplifier to reduce investment and operation costs. The inductive power coupler will be located at the RFQ part. The coupling into the IH – section is provided by direct inductive coupling within the cavity. The coupled RFQ-IH combination is investigated with CST-MWS-simulations and by an RF model. The linac combination has to match the resonance frequency, flatness along the RFQ and the voltage ratio between both cavity sections. Beam operation will be cw (a few mA) and pulsed 250 kHz, 50 ns (up to 50 mA and beyond). The thermal cavity losses are about 200 kW and the cooling is the challenging topic.

THPWO021

Gabor Lens Performance Studies at the GSI High Current Test Injector

3806

K. Schulte, M. Droba, O. Meusel, U. Ratzinger
IAP, Frankfurt am Main, Germany
A. Adonin, R. Berezov, R. Hollinger, J. Pfister
GSI, Darmstadt, Germany

At the Institute for Applied Physics (IAP) the application of Gabor space charge lenses as a focusing device for low energy ion beams has already been studied for several years. Inside Gabor lenses electrons are confined by external fields. In case of a homogeneously distributed electron cloud the resulting linear electric space charge field enables the focusing of high intensity heavy ion beams without aberrations. Therefore, the Gabor lens is a promising approach for mass-independent focusing and possible space charge compensation of ion beams. In mid-2012 the performance of a prototype lens has successfully been tested at the GSI High Current Test Injector (HOSTI). GSI and IAP are currently investigating the possible application of such a device for the continuous operation at the High Current Injector (HSI) for FAIR. This contribution will present the results of beam transport experiments at HOSTI as well as the determination of related plasma properties.