IPAC2022 - List of Authors (Droba, M.)

Paper	Title	Page
MOPOST016	Proton Linac Design for the High Brilliance Neutron Source HBS	90
	M. Schwarz, M. Droba, K. Kümpel, S. Lamprecht, O. Meusel, N.F. Petry, H. Podlech IAP, Frankfurt am Main, Germany J. Baggemann, Th. Brückel, T. Gutberlet, E. Mauerhofer, U. Rücker, A. Schwab, P. Zakalek JCNS, Jülich, Germany J. Li IEK, Jülich, Germany C. Zhang GSI, Darmstadt, Germany
	Due to the decommissioning of several reactors, only about half of the neutrons will be available for research in Europe in the next decade despite the commissioning of the ESS. High-Current Accelerator-driven Neutron Sources (HiCANS) could fill this gap. The High Brilliance Neutron Source (HBS) currently under development at Forschungszentrum Jülich is scalable in terms of beam energy and power due to its modular design. The driver linac will accelerate a 100 mA proton beam to 70 MeV. The linac is operated with a beam duty cycle of up to 13.6 % (15.3 % RF duty cycle) and can simultaneously deliver three pulse lengths (208 µs, 833 µs and 2 ms) for three neutron target stations. In order to minimize the development effort and the technological risk, state-of-the-art technology of the MYRRHA injector is used. The HBS linac consists of a front end (ECR source, LEBT, 2.5 MeV double RFQ) and a CH-DTL section with 44 room temperature CH-cavities. All RF structures are operated at 176.1 MHz and are designed for high duty cycle. Solid-state amplifiers up to 500 kW are used as RF drivers. Due to the beam current and the high average beam power of up to 952 kW, particular attention is paid to beam dynamics. In order to minimize beam losses, a quasi-periodic lattice with constant negative phase is used. This paper describes the conceptual design and the challenges of a modern high-power and high-current proton accelerator with high reliability and availability.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST016
About •	Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 11 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOTK011	Generalisation and Longitudinal Extension of the Genetic Lattice Construction (GLC) Algorithm	453
	S. Reimann, M. Droba, O. Meusel, H. Podlech IAP, Frankfurt am Main, Germany H. Podlech HFHF, Frankfurt am Main, Germany S. Reimann GSI, Darmstadt, Germany
	The GLC algorithm allows the construction of efficient transfer lines with defined imaging properties using a minimum number of quadrupole elements. This work describes a generalization of this algorithm to make it applicable to the use of arbitrary beam optical elements. This includes an extension to longitudinal phase space.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK011
About •	Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 01 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOMS017	Beam Transport Simulations Through Final Focus High Energy Transport Lines with Implemented Gabor Lenses	663
	A. Sherjan, M. Droba, O. Meusel, S. Reimann, K.I. Thoma IAP, Frankfurt am Main, Germany S. Reimann GSI, Darmstadt, Germany
	First investigations on Gabor Lens GL2000 at Goethe University have shown that it is possible to confine a 2m long stable Electron Plasma Column and to apply it as a hadron beam focusing device. With this knowledge theoretical implementations of GLs in final focus and transfer lines have started. The focusing with GLs is a weak but smooth focusing in radial direction. The GL is a suitable and inexpensive choice in addition to the existing focusing elements eg. magnetic quadrupoles. The device helps to improve beam quality and minimize losses over long distances. The investigation of relativistic hadron beams in GeV range using the example of the proposed NA61/SHINE VLE-beamline at CERN is carried out and will be presented. Thin-matrix simulations with a generated distribution as well as field map simulations with generated and realistic distributions (Geant4) at 1 - 6 GeV/c have been analysed and compared. In addition, the H4-beamline at North Area (CERN) is proposed to implement GLs for experimental tests.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS017
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 14 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOMS018	Tungsten Electron Emitter (TE²) with Direct Heated Cathode by Plasma Stream	667
	K.I. Thoma, M. Droba, T. Dönges, O. Meusel, H. Podlech, K. Schulte-Urlichs IAP, Frankfurt am Main, Germany K. Schulte-Urlichs, K.I. Thoma GSI, Darmstadt, Germany
	At Goethe-University, a novel concept of heating metallic cathodes is currently under investigation. In the scope of the ARIES collaboration WP16, an RF-modulated electron gun was developed and manufactured for application in electron lenses for space charge compensation. The goal of this project is to increase the intensity of primary beams, especially in low energy booster synchrotrons like the SIS18 and SIS100 at GSI/FAIR or the SPS at CERN. The gun was designed to produce electron currents of 10 A at extraction voltages of 30 kV. The tungsten electron emitter (TE²) and the grid electrode were designed and manufactured to be integrated in the extractor of the original volume type ion source. Significant effort was put into a robust and flexible design with highly reliable key components. The cathode is heated by a plasma stream generated in the plasma chamber of the source. Different heating options of the cathode are currently being studied. This contribution presents the working principles of the electron gun and first measurements results of cathode heating.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS018
About •	Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 26 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOTK002	Investigation, Simulation and First Measurements of a 2m Long Electron Column Trapped in a Gabor Lens Device	2023
	K.I. Thoma, M. Droba, O. Meusel IAP, Frankfurt am Main, Germany
	Various Gabor-Lenses (GL) were investigated at Goethe University. Confinement of sufficient electron densities (ne~1E15m³) were reached without any external source of electrons. Focusing of ion beams by low energy was demonstrated, long term stability and reproducibility were approved. Main differences compared to experiments and investigations of the pure non-neutral in Penning-Malmberg traps are higher residual gas pressure and therefore higher collision rates, higher bulk temperatures, self-sustaining electron production process, much higher evaporation cooling rate. GL2000 is a new 2m long device and was mainly designed for focusing of ion beams in energy ranges up to GeV but also for investigation of non-neutral plasma parameters. The confined electron column is much longer compared to previous constructed Lenses. This makes ion and hadron beam focussing much more efficient, in addition new physical phenomena can be expected and investigated. Simulation results of steady- and thermal equilibrium states with various external parameters and first measurements will be presented. The first operational tests show that it is possible to confine a two-meter long electron column.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK002
About •	Received ※ 20 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 22 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOTK003	Status of the Development of the Electron Lens for Space Charge Compensation at GSI	2027
	K. Schulte-Urlichs, D. Ondreka, P.J. Spiller, K.I. Thoma GSI, Darmstadt, Germany M. Droba, T. Dönges, O. Meusel, H. Podlech IAP, Frankfurt am Main, Germany
	At GSI a prototype electron lens for space charge (SC) compensation is currently being designed and main components as the RF-modulated electron gun are already under commissioning. The goal of this project is the (partial) compensation of SC forces within the ion beam by an overlapping electron beam. This may help to increase the intensity of primary beams, especially in the FAIR facility and potentially all large synchrotrons operated at the SC limit. For an effective SC compensation, the generated electron beam needs to follow the transverse and longitudinal beam profile of the ion bunch structure. The requirements are maximum currents of 10 A and grid modulation to cover a broad frequency range from 400 kHz to 1 MHz. The RF-modulated electron gun was designed and manufactured in the scope of the ARIES collaboration and is currently being tested at the E-Lens Lab of Goethe University Frankfurt. A dedicated test bench was built for commissioning of the major e-lens components and diagnostics. In this contribution the overall set-up will be presented putting special emphasis on the beam dynamics and collector design as well as as well as simulation results of the electron gun.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK003
About •	Received ※ 18 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 07 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOMS021	Entropy Production and Emittance Growth Due to the Imperfection in Long Periodical Acceleration Chains	2286
	M. Droba, O. Meusel, H. Podlech, S. Reimann IAP, Frankfurt am Main, Germany H. Podlech HFHF, Frankfurt am Main, Germany S. Reimann GSI, Darmstadt, Germany
	Contemporary design of efficient linear accelerator is based on ideal periodical structures with an optimi-sation for perfect periodicity. However, practical reali-sation involves random errors in the structure (e.g. position of elements, off-sets, non-linearity of the fields etc.) which make prediction of emittance growth difficult. Error studies helps to understand critical points, but they are normally used at the end of the design process. The concept of beam entropy in very simple approximation (assumption of Ornstein-Uhlenbeck model) is used to evaluate emittance growth in perfect periodical chains. The analysis will be performed and differences in modern designs on some examples discussed. Focus will be laid on linac designs with short acceleration structures (RF-phase settings versus position error) and external transversal focusing magnets.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS021
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 23 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Proton Linac Design for the High Brilliance Neutron Source HBS

90

M. Schwarz, M. Droba, K. Kümpel, S. Lamprecht, O. Meusel, N.F. Petry, H. Podlech
IAP, Frankfurt am Main, Germany
J. Baggemann, Th. Brückel, T. Gutberlet, E. Mauerhofer, U. Rücker, A. Schwab, P. Zakalek
JCNS, Jülich, Germany
J. Li
IEK, Jülich, Germany
C. Zhang
GSI, Darmstadt, Germany

Due to the decommissioning of several reactors, only about half of the neutrons will be available for research in Europe in the next decade despite the commissioning of the ESS. High-Current Accelerator-driven Neutron Sources (HiCANS) could fill this gap. The High Brilliance Neutron Source (HBS) currently under development at Forschungszentrum Jülich is scalable in terms of beam energy and power due to its modular design. The driver linac will accelerate a 100 mA proton beam to 70 MeV. The linac is operated with a beam duty cycle of up to 13.6 % (15.3 % RF duty cycle) and can simultaneously deliver three pulse lengths (208 µs, 833 µs and 2 ms) for three neutron target stations. In order to minimize the development effort and the technological risk, state-of-the-art technology of the MYRRHA injector is used. The HBS linac consists of a front end (ECR source, LEBT, 2.5 MeV double RFQ) and a CH-DTL section with 44 room temperature CH-cavities. All RF structures are operated at 176.1 MHz and are designed for high duty cycle. Solid-state amplifiers up to 500 kW are used as RF drivers. Due to the beam current and the high average beam power of up to 952 kW, particular attention is paid to beam dynamics. In order to minimize beam losses, a quasi-periodic lattice with constant negative phase is used. This paper describes the conceptual design and the challenges of a modern high-power and high-current proton accelerator with high reliability and availability.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST016

About •

Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 11 July 2022

Cite •

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

MOPOTK011

Generalisation and Longitudinal Extension of the Genetic Lattice Construction (GLC) Algorithm

453

S. Reimann, M. Droba, O. Meusel, H. Podlech
IAP, Frankfurt am Main, Germany
H. Podlech
HFHF, Frankfurt am Main, Germany
S. Reimann
GSI, Darmstadt, Germany

The GLC algorithm allows the construction of efficient transfer lines with defined imaging properties using a minimum number of quadrupole elements. This work describes a generalization of this algorithm to make it applicable to the use of arbitrary beam optical elements. This includes an extension to longitudinal phase space.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK011

About •

Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 01 July 2022

Cite •

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

MOPOMS017

Beam Transport Simulations Through Final Focus High Energy Transport Lines with Implemented Gabor Lenses

663

A. Sherjan, M. Droba, O. Meusel, S. Reimann, K.I. Thoma
IAP, Frankfurt am Main, Germany
S. Reimann
GSI, Darmstadt, Germany

First investigations on Gabor Lens GL2000 at Goethe University have shown that it is possible to confine a 2m long stable Electron Plasma Column and to apply it as a hadron beam focusing device. With this knowledge theoretical implementations of GLs in final focus and transfer lines have started. The focusing with GLs is a weak but smooth focusing in radial direction. The GL is a suitable and inexpensive choice in addition to the existing focusing elements eg. magnetic quadrupoles. The device helps to improve beam quality and minimize losses over long distances. The investigation of relativistic hadron beams in GeV range using the example of the proposed NA61/SHINE VLE-beamline at CERN is carried out and will be presented. Thin-matrix simulations with a generated distribution as well as field map simulations with generated and realistic distributions (Geant4) at 1 - 6 GeV/c have been analysed and compared. In addition, the H4-beamline at North Area (CERN) is proposed to implement GLs for experimental tests.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS017

About •

Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 14 June 2022

Cite •

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

MOPOMS018

Tungsten Electron Emitter (TE²) with Direct Heated Cathode by Plasma Stream

667

K.I. Thoma, M. Droba, T. Dönges, O. Meusel, H. Podlech, K. Schulte-Urlichs
IAP, Frankfurt am Main, Germany
K. Schulte-Urlichs, K.I. Thoma
GSI, Darmstadt, Germany

At Goethe-University, a novel concept of heating metallic cathodes is currently under investigation. In the scope of the ARIES collaboration WP16, an RF-modulated electron gun was developed and manufactured for application in electron lenses for space charge compensation. The goal of this project is to increase the intensity of primary beams, especially in low energy booster synchrotrons like the SIS18 and SIS100 at GSI/FAIR or the SPS at CERN. The gun was designed to produce electron currents of 10 A at extraction voltages of 30 kV. The tungsten electron emitter (TE²) and the grid electrode were designed and manufactured to be integrated in the extractor of the original volume type ion source. Significant effort was put into a robust and flexible design with highly reliable key components. The cathode is heated by a plasma stream generated in the plasma chamber of the source. Different heating options of the cathode are currently being studied. This contribution presents the working principles of the electron gun and first measurements results of cathode heating.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS018

About •

Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 26 June 2022

Cite •

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

WEPOTK002

Investigation, Simulation and First Measurements of a 2m Long Electron Column Trapped in a Gabor Lens Device

2023

K.I. Thoma, M. Droba, O. Meusel
IAP, Frankfurt am Main, Germany

Various Gabor-Lenses (GL) were investigated at Goethe University. Confinement of sufficient electron densities (ne~1E15m³) were reached without any external source of electrons. Focusing of ion beams by low energy was demonstrated, long term stability and reproducibility were approved. Main differences compared to experiments and investigations of the pure non-neutral in Penning-Malmberg traps are higher residual gas pressure and therefore higher collision rates, higher bulk temperatures, self-sustaining electron production process, much higher evaporation cooling rate. GL2000 is a new 2m long device and was mainly designed for focusing of ion beams in energy ranges up to GeV but also for investigation of non-neutral plasma parameters. The confined electron column is much longer compared to previous constructed Lenses. This makes ion and hadron beam focussing much more efficient, in addition new physical phenomena can be expected and investigated. Simulation results of steady- and thermal equilibrium states with various external parameters and first measurements will be presented. The first operational tests show that it is possible to confine a two-meter long electron column.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK002

About •

Received ※ 20 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 22 June 2022

Cite •

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

WEPOTK003

Status of the Development of the Electron Lens for Space Charge Compensation at GSI

2027

K. Schulte-Urlichs, D. Ondreka, P.J. Spiller, K.I. Thoma
GSI, Darmstadt, Germany
M. Droba, T. Dönges, O. Meusel, H. Podlech
IAP, Frankfurt am Main, Germany

At GSI a prototype electron lens for space charge (SC) compensation is currently being designed and main components as the RF-modulated electron gun are already under commissioning. The goal of this project is the (partial) compensation of SC forces within the ion beam by an overlapping electron beam. This may help to increase the intensity of primary beams, especially in the FAIR facility and potentially all large synchrotrons operated at the SC limit. For an effective SC compensation, the generated electron beam needs to follow the transverse and longitudinal beam profile of the ion bunch structure. The requirements are maximum currents of 10 A and grid modulation to cover a broad frequency range from 400 kHz to 1 MHz. The RF-modulated electron gun was designed and manufactured in the scope of the ARIES collaboration and is currently being tested at the E-Lens Lab of Goethe University Frankfurt. A dedicated test bench was built for commissioning of the major e-lens components and diagnostics. In this contribution the overall set-up will be presented putting special emphasis on the beam dynamics and collector design as well as as well as simulation results of the electron gun.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK003

About •

Received ※ 18 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 07 July 2022

Cite •

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

WEPOMS021

Entropy Production and Emittance Growth Due to the Imperfection in Long Periodical Acceleration Chains

2286

M. Droba, O. Meusel, H. Podlech, S. Reimann
IAP, Frankfurt am Main, Germany
H. Podlech
HFHF, Frankfurt am Main, Germany
S. Reimann
GSI, Darmstadt, Germany

Contemporary design of efficient linear accelerator is based on ideal periodical structures with an optimi-sation for perfect periodicity. However, practical reali-sation involves random errors in the structure (e.g. position of elements, off-sets, non-linearity of the fields etc.) which make prediction of emittance growth difficult. Error studies helps to understand critical points, but they are normally used at the end of the design process. The concept of beam entropy in very simple approximation (assumption of Ornstein-Uhlenbeck model) is used to evaluate emittance growth in perfect periodical chains. The analysis will be performed and differences in modern designs on some examples discussed. Focus will be laid on linac designs with short acceleration structures (RF-phase settings versus position error) and external transversal focusing magnets.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS021

About •

Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 23 June 2022

Cite •

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