LINAC2016 - List of Authors (Ratzinger, U.)

Paper	Title	Page
MOPRC018	Improved Beam Dynamics and Cavity RF Design for the FAIR Proton Injector	111
MOOP06	use link to see paper's listing under its alternate paper code
	R. Tiede, A. Almomani, M. Busch, F.D. Dziuba, U. Ratzinger IAP, Frankfurt am Main, Germany
	The FAIR facility at GSI requires a dedicated 70 MeV, 70 mA proton injector for the research program with intense antiproton beams. The main accelerator part consists of six 'Crossbar H-type' (CH) cavities operated at 325 MHz. Based on a linac layout carefully developed over several years, recently the beam dynamics has been revised with the scope of finalising the design and thus being able to start the construction of the main linac components. As compared to previous designs the MEBT behind the RFQ was slightly extended, the gap numbers per CH cavity and the voltage distributions were optimised and the layout of the intermediate diagnostics section including a rebuncher cavity at 33 MeV was redesigned. Finally, detailed machine error studies were performed in order to check the error response of the new design and the steering concept in particular. In the consequence, the final parameters obtained from the beam dynamics update are used for finalizing the CH-DTL cavity design by CST-MWS calculations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPRC018
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLR053	Development and Measurements of a 325 MHz RFQ	578
SPWR026	use link to see paper's listing under its alternate paper code
	M. Schütt, M.A. Obermayer, U. Ratzinger IAP, Frankfurt am Main, Germany A. Schnase GSI, Darmstadt, Germany
	In order to have an inexpensive alternative to 4-Vane RFQs above 200 MHz, we study the possibilities of a Ladder-RFQ. The 325 MHz RFQ is designed to accelerate protons from 95 keV to 3.0 MeV according to the design parameters of the research program with cooled antiprotons at FAIR. This particular high frequency for an RFQ creates difficulties, which are challenging in developing a cavity, especially for 4-ROD RFQs, which dimensions become critically small with increasing the frequency. In order to define a satisfying geometrical configuration for this resonator, both from the RF and the mechanical point of view, different designs have been examined and compared. Very promising results were reached with a ladder type RFQ, which has been investigated since 2013. Due to its geometry, the manufacturing in terms of complexity, time and costs is more beneficial compared to welded accelerators. Furthermore, maintenance is easy to handle. The manufacturing, coppering and assembling of a 0.8 m prototype RFQ is finished. We present recent measurements of the RF-field including power measurements, frequency-tuning, field flatness as well as power measurements.
	Poster TUPLR053 [47.463 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUPLR053
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLR070	Efficient Heavy Ion Acceleration with IH-Type Cavities for High Current Machines in the Energy Range up to 11.4 MeV/u	616
	H. Hähnel, U. Ratzinger, R. Tiede IAP, Frankfurt am Main, Germany
	Funding: BMBF 05P15RFRBA We propose an efficient design for heavy ion acceleration from 1.4 to 11.4 MeV/u with a design current of 15 emA for a Uranium 28+ beam. The proposed linac is based on IH-DTL cavities and quadrupole triplet focusing. The KONUS beam dynamics concept is used to achieve high acceleration efficiency. By optimization of the transversal focusing scheme and the longitudinal bunch center motion, low emittance growth for the entire linac is achieved. Beam dynamics simulations were performed along with 3D rf-simulations of all cavities. The cavities are designed for 10⁸.408 MHz, reaching an effective shunt impedance of 100-200 MOhm/m. The overall length of the linac is below 25 m. A mechanical realization concept employing a modular tank design is presented. The proposed design is a viable option for the GSI UNILAC poststripper linac replacement, leaving free space in the UNILAC tunnel for future energy upgrades.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUPLR070
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPLR029	Update on the SC 325 MHz CH-Cavity and Power Coupler Processing	913
	M. Busch, M. Amberg, M. Basten, F.D. Dziuba, P.A. Mundine, H. Podlech, U. Ratzinger IAP, Frankfurt am Main, Germany
	Funding: Work supported by GSI, BMBF Contr. No. 05P15RFRBA The 325 MHz CH-Cavity which has been developed and successfully vertically tested at the Institute for Applied Physics, Frankfurt, has reached the final production stage. The helium vessel has been welded to the frontal joints of the cavity and further tests in a horizontal environment are in preparation. Furthermore the corresponding power couplers have been conditioned and tested at a dedicated test stand up to the power level of 40 kW (pulsed) for the targeted beam operation. The final step of the whole prototype development is a beam test with a 11.4 AMeV, 10 mA ion beam at GSI, Darmstadt.
	Poster THPLR029 [1.858 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR029
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPLR059	Status of a 325 MHz High Gradient CH - Cavity	982
	A. Almomani, U. Ratzinger IAP, Frankfurt am Main, Germany
	Funding: BMBF with contract number 05P12RFRB9 The reported linac developments aim on compact ion accelerators and on an increase of the effective accelerat-ing field (voltage gain per meter). Within a funded pro-ject, a high gradient Crossbar H-type CH-cavity operat-ed at 325 MHz was developed and successfully built at IAP-Frankfurt. The effective accelerating field for this cavity is expected to reach about 13.3 MV/m at a beam energy of 12.5 AMeV, corresponding to β=0.164. The results from this cavity might influence the later energy upgrade of the Unilac at GSI Darmstadt. The aim is a compact pulsed high current ion accelerator for significantly higher energies up to 200 AMeV. Detailed investigations for two different types of copper plating (high lustre and lustre less) with respect to the high spark limit will be performed on this cavity. The 325 MHz GSI 3 MW klystron test stand is best suited for these investigations. Additionally, operating of normal conducting cavities for the case of very short RF pulses will be discussed at cryogenic temperature.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR059
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

MOPRC018

Improved Beam Dynamics and Cavity RF Design for the FAIR Proton Injector

111

MOOP06

use link to see paper's listing under its alternate paper code

R. Tiede, A. Almomani, M. Busch, F.D. Dziuba, U. Ratzinger
IAP, Frankfurt am Main, Germany

The FAIR facility at GSI requires a dedicated 70 MeV, 70 mA proton injector for the research program with intense antiproton beams. The main accelerator part consists of six 'Crossbar H-type' (CH) cavities operated at 325 MHz. Based on a linac layout carefully developed over several years, recently the beam dynamics has been revised with the scope of finalising the design and thus being able to start the construction of the main linac components. As compared to previous designs the MEBT behind the RFQ was slightly extended, the gap numbers per CH cavity and the voltage distributions were optimised and the layout of the intermediate diagnostics section including a rebuncher cavity at 33 MeV was redesigned. Finally, detailed machine error studies were performed in order to check the error response of the new design and the steering concept in particular. In the consequence, the final parameters obtained from the beam dynamics update are used for finalizing the CH-DTL cavity design by CST-MWS calculations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPRC018

Export •

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

TUPLR053

Development and Measurements of a 325 MHz RFQ

578

SPWR026

use link to see paper's listing under its alternate paper code

M. Schütt, M.A. Obermayer, U. Ratzinger
IAP, Frankfurt am Main, Germany
A. Schnase
GSI, Darmstadt, Germany

In order to have an inexpensive alternative to 4-Vane RFQs above 200 MHz, we study the possibilities of a Ladder-RFQ. The 325 MHz RFQ is designed to accelerate protons from 95 keV to 3.0 MeV according to the design parameters of the research program with cooled antiprotons at FAIR. This particular high frequency for an RFQ creates difficulties, which are challenging in developing a cavity, especially for 4-ROD RFQs, which dimensions become critically small with increasing the frequency. In order to define a satisfying geometrical configuration for this resonator, both from the RF and the mechanical point of view, different designs have been examined and compared. Very promising results were reached with a ladder type RFQ, which has been investigated since 2013. Due to its geometry, the manufacturing in terms of complexity, time and costs is more beneficial compared to welded accelerators. Furthermore, maintenance is easy to handle. The manufacturing, coppering and assembling of a 0.8 m prototype RFQ is finished. We present recent measurements of the RF-field including power measurements, frequency-tuning, field flatness as well as power measurements.

Poster TUPLR053 [47.463 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUPLR053

Export •

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

TUPLR070

Efficient Heavy Ion Acceleration with IH-Type Cavities for High Current Machines in the Energy Range up to 11.4 MeV/u

616

H. Hähnel, U. Ratzinger, R. Tiede
IAP, Frankfurt am Main, Germany

Funding: BMBF 05P15RFRBA
We propose an efficient design for heavy ion acceleration from 1.4 to 11.4 MeV/u with a design current of 15 emA for a Uranium 28+ beam. The proposed linac is based on IH-DTL cavities and quadrupole triplet focusing. The KONUS beam dynamics concept is used to achieve high acceleration efficiency. By optimization of the transversal focusing scheme and the longitudinal bunch center motion, low emittance growth for the entire linac is achieved. Beam dynamics simulations were performed along with 3D rf-simulations of all cavities. The cavities are designed for 10⁸.408 MHz, reaching an effective shunt impedance of 100-200 MOhm/m. The overall length of the linac is below 25 m. A mechanical realization concept employing a modular tank design is presented. The proposed design is a viable option for the GSI UNILAC poststripper linac replacement, leaving free space in the UNILAC tunnel for future energy upgrades.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUPLR070

Export •

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

THPLR029

Update on the SC 325 MHz CH-Cavity and Power Coupler Processing

913

M. Busch, M. Amberg, M. Basten, F.D. Dziuba, P.A. Mundine, H. Podlech, U. Ratzinger
IAP, Frankfurt am Main, Germany

Funding: Work supported by GSI, BMBF Contr. No. 05P15RFRBA
The 325 MHz CH-Cavity which has been developed and successfully vertically tested at the Institute for Applied Physics, Frankfurt, has reached the final production stage. The helium vessel has been welded to the frontal joints of the cavity and further tests in a horizontal environment are in preparation. Furthermore the corresponding power couplers have been conditioned and tested at a dedicated test stand up to the power level of 40 kW (pulsed) for the targeted beam operation. The final step of the whole prototype development is a beam test with a 11.4 AMeV, 10 mA ion beam at GSI, Darmstadt.

Poster THPLR029 [1.858 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR029

Export •

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

THPLR059

Status of a 325 MHz High Gradient CH - Cavity

982

A. Almomani, U. Ratzinger
IAP, Frankfurt am Main, Germany

Funding: BMBF with contract number 05P12RFRB9
The reported linac developments aim on compact ion accelerators and on an increase of the effective accelerat-ing field (voltage gain per meter). Within a funded pro-ject, a high gradient Crossbar H-type CH-cavity operat-ed at 325 MHz was developed and successfully built at IAP-Frankfurt. The effective accelerating field for this cavity is expected to reach about 13.3 MV/m at a beam energy of 12.5 AMeV, corresponding to β=0.164. The results from this cavity might influence the later energy upgrade of the Unilac at GSI Darmstadt. The aim is a compact pulsed high current ion accelerator for significantly higher energies up to 200 AMeV. Detailed investigations for two different types of copper plating (high lustre and lustre less) with respect to the high spark limit will be performed on this cavity. The 325 MHz GSI 3 MW klystron test stand is best suited for these investigations. Additionally, operating of normal conducting cavities for the case of very short RF pulses will be discussed at cryogenic temperature.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR059

Export •

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