IPAC2017 - List of Authors (Neumann, A.)

Paper	Title	Page
MOPVA005	Status of the Berlin Energy Recovery Linac Project BERLinPro	855
	M. Abo-Bakr, W. Anders, K.B. Bürkmann-Gehrlein, A.B. Büchel, P. Echevarria, A. Frahm, H.-W. Glock, F. Glöckner, F. Göbel, B.D.S. Hall, S. Heling, H.-G. Hoberg, A. Jankowiak, C. Kalus, T. Kamps, G. Klemz, J. Knedel, J. Knobloch, J. Kolbe, G. Kourkafas, J. Kühn, B.C. Kuske, J. Kuszynski, D. Malyutin, A.N. Matveenko, M. McAteer, A. Meseck, C.J. Metzger-Kraus, R. Müller, A. Neumann, N. Ohm, K. Ott, E. Panofski, F. Pflocksch, J. Rahn, M. Schmeißer, O. Schüler, M. Schuster, J. Ullrich, A. Ushakov, J. Völker HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association. The Helmholtz-Zentrum Berlin is constructing the Energy Recovery Linac Prototype BERLinPro, a demonstration facility for the science and technology of ERLs for future light source applications. BERLinPro is designed to accelerate a high current (100 mA, 50 MeV), high brilliance (norm. emittance below 1 mm mrad) cw electron beam. We report on the project status. This includes the completion of the building and the installation of the first accelerator components as well as the assembly of the SRF gun and GunLab beam diagnostics, which are now ready for commissioning.
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MOPVA010	Setup and Status of an SRF Photoinjector for Energy-Recovery Linac Applications	865
	T. Kamps, D. Böhlick, A.B. Büchel, M. Bürger, P. Echevarria, A. Frahm, F. Göbel, S. Heling, A. Jankowiak, S. Keckert, H. Kirschner, G. Klemz, J. Knobloch, G. Kourkafas, J. Kühn, O. Kugeler, A.N. Matveenko, A. Neumann, N. Ohm-Krafft, E. Panofski, F. Pfloksch, S. Rotterdam, M.A.H. Schmeißer, M. Schuster, H. Stein, J. Ullrich, A. Ushakov, J. Völker HZB, Berlin, Germany I. Will MBI, Berlin, Germany
	Funding: The work is funded by the Helmholtz-Association, BMBF, the state of Berlin and HZB. The Superconducting RF (SRF) photoinjector programme for the energy-recovery linac (ERL) test facility BERLinPro sets out to push the brightness and average current limits for ERL electron sources by tackling the main challenges related to beam dynamics of SRF photoinjectors, the incorporation of high quantum efficiency (QE) photocathodes, and suppression of unwanted beam generation. The paper details the experimental layout of the SRF photoinjector and the gun test facility GunLab at Helmholtz-Zentrum Berlin.
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MOPVA046	120kW RF Power Input Couplers for BERLinPro	960
	B.D.S. Hall, V. Dürr, F. Göbel, J. Knobloch, A. Neumann HZB, Berlin, Germany
	The 50-MeV, 100-mA energy-recovery-linac (ERL) demonstration facility BERLinPro is currently undergoing construction at HZB. The high power injection system, that will deliver a beam at 6.5MeV, is split into a 1.4 cell SRF Photo injector and three Cornell-style 2-cell boosters. The injector and two of the booster cavities will provide about 2MeV each and must handle up to 220 kW of beam loading. New, cERL-based 115-kW high power couplers needed for the cavities' twin coupler system have begun manufacture. The design, optimization and manufacturing considerations of these couplers are presented.
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MOPVA049	First Commissioning of an SRF Photo-Injector Module for BERLinPro	971
	A. Neumann, A. Burrill, D. Böhlick, A.B. Büchel, M. Bürger, P. Echevarria, A. Frahm, H.-W. Glock, F. Göbel, S. Heling, K. Janke, T. Kamps, S. Keckert, S. Klauke, G. Klemz, J. Knobloch, G. Kourkafas, J. Kühn, O. Kugeler, N. Ohm, E. Panofski, H. Plötz, S. Rotterdam, M. Schenk, M.A.H. Schmeißer, M. Schuster, H. Stein, Y. Tamashevich, J. Ullrich, A. Ushakov, J. Völker HZB, Berlin, Germany A. Matheisen, M. Schmökel DESY, Hamburg, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association. Helmholtz-Zentrum Berlin (HZB) is currently building an high average current superconducting ERL to demonstrate ERL operation with low normalized beam emittance of 1 mm·mrad at 100mA and short pulses of about 2 ps. For the injector section a series of SRF photoinjector cavities is being developed. The medium power prototype presented here features a 1.4 x λ/2 cell SRF cavity with a normal-conducting, high quantum efficiency CsK2Sb cathode, implementing a modified HZDR-style cathode insert. This injector potentially allows for 6 mA beam current at up to 3.5 MeV kinetic energy. In this contribution, the first RF commissioning results of the photo-injector module will be presented and compared to the level of performance during the cavity production and string assembly process.
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MOPVA053	The SRF Module Developments for BESSY VSR	986
	A.V. Vélez, H.-W. Glock, F. Glöckner, B.D.S. Hall, J. Knobloch, A. Neumann, P. Schnizer, E. Sharples, A.V. Tsakanian HZB, Berlin, Germany
	Helmholtz-Zentrum Berlin is developing BESSY VSR, a novel upgrade of the BESSY II facility to provide highly flexible pulse lengths while maintaining the flux and brilliance. The project goal is to simultaneously circulate both standard (some 10 ps long) and short (ps and sub-ps long) pulses offering the BESSY user community picosecond dynamics and high-resolution experiments. The concept relies on the installation of high-voltage SRF cavities operating at the 3rd and 3.5th harmonic whereby the beating of the two frequencies provides RF buckets for long and short bunches. Since these cavities will operate in CW and with high beam current (Ib=300 mA), the cavity design represents a challenging goal. In addition the need to avoid coupled bunch instabilities (CBI's), the installation of the VSR Cryomodule must fit in one of the available 4-m long low beta straights. To address the technological and engineering challenges techniques such as waveguide-damped cavities have been developed. First prototypes have been produced. In this paper, the present SRF developments are presented, including the cavities, high power couplers, higher-order mode absorbers and the cryomodule design.
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MOPVA130	Development of Waveguide HOM Loads for BERLinPro and BESSY-VSR SRF Cavities	1160
	J. Guo, F. Fors, J. Henry, R.A. Rimmer, H. Wang JLab, Newport News, Virginia, USA H.-W. Glock, A. Neumann, A.V. Tsakanian, A.V. Vélez HZB, Berlin, Germany
	Two ongoing accelerator projects at Helmholtz-Zentrum Berlin (HZB), BERLinPro and BESSY-VSR, need to design three different SRF cavities, a 1.3GHz cavity in BERLinPro and 1.5GHz/1.75GHz cavities in BESSY-VSR. These cavities have adopted waveguide HOM dampers in their design, with a few tens of watts HOM power in each load for BERLinPro and a few hundred watts for BESSY-VSR. JLab is collaborating with HZB prototyping these HOM loads. In this paper, we will report on the integrated RF-thermal-mechanical design of the loads, as well as the fabrication and testing results.
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TUPAB027	Production, Tuning and Processing Challenges of the BERLinPro Gun1.1 Cavity	1375
	H.-W. Glock, A. Frahm, J. Knobloch, A. Neumann HZB, Berlin, Germany B. Rosin, D. Trompetter RI Research Instruments GmbH, Bergisch Gladbach, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of the Helmholtz Association For the BERLinPro energy recovery LINAC, HZB is developing a superconducting 1.4-cell electron gun, which, in its final version, is planned to be capable of CW 1.3 GHz operation with 77 pC/bunch. For this purpose a series of three superconducting cavities, denoted as Gun 1.0, Gun 1.1 (both designed for 6 mA) and Gun 2.0 (100 mA) are foreseen. Gun 1.0 now reached operational status and the Gun 1.1 cavity is completely manufactured. In the paper the chronology of manufacturing, tuning and processing of the Gun 1.1-cavity is described, also giving details about combined mechanical/electrodynamic simulations, which were performed in order to gain deeper understanding of the cavity's unexpected tuning behavior.
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THPAB095	Detuning Compensation in SC Cavities Using Kalman Filters	3938
	A. Ushakov, P. Echevarria, A. Neumann HZB, Berlin, Germany
	For CW driven superconducting cavities operating at small bandwidth, like in ERL or FEL light sources, it is mandatory to precisely control any source of detuning. Therefore, a Kalman [1] filter based approach was developed and implemented as FPGA firmware to act as the core part of a detuning compensation algorithm. It relies on a fit by a second order model to a measured transfer function of cavity's forced oscillations with damping, caused by piezo drives and data about observed current phase with some adjustable confidence rate. The initial data for this core is taken from field detection firmware on mTCA.4's SIS8300-L2 digitizer, transferred by low latency links to a carrier board equipped by piezo drive controller where the DSP processing by the Kalman algorithm performed. The processing is characterized by a 550 kHz rate in pipeline mode and occupies almost all DSP resources of the Spartan 6 FPGA chip. The experimental results of detuning compensating technique applied to a SC photoinjector cavity are presented in this contribution. Kalman, R. E. (1960): A New Approach to Linear Filtering and Prediction Problems, Transaction of the ASME, Journal of Basic Engineering, Pages 35-45.
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Paper

Title

Page

Status of the Berlin Energy Recovery Linac Project BERLinPro

855

M. Abo-Bakr, W. Anders, K.B. Bürkmann-Gehrlein, A.B. Büchel, P. Echevarria, A. Frahm, H.-W. Glock, F. Glöckner, F. Göbel, B.D.S. Hall, S. Heling, H.-G. Hoberg, A. Jankowiak, C. Kalus, T. Kamps, G. Klemz, J. Knedel, J. Knobloch, J. Kolbe, G. Kourkafas, J. Kühn, B.C. Kuske, J. Kuszynski, D. Malyutin, A.N. Matveenko, M. McAteer, A. Meseck, C.J. Metzger-Kraus, R. Müller, A. Neumann, N. Ohm, K. Ott, E. Panofski, F. Pflocksch, J. Rahn, M. Schmeißer, O. Schüler, M. Schuster, J. Ullrich, A. Ushakov, J. Völker
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association.
The Helmholtz-Zentrum Berlin is constructing the Energy Recovery Linac Prototype BERLinPro, a demonstration facility for the science and technology of ERLs for future light source applications. BERLinPro is designed to accelerate a high current (100 mA, 50 MeV), high brilliance (norm. emittance below 1 mm mrad) cw electron beam. We report on the project status. This includes the completion of the building and the installation of the first accelerator components as well as the assembly of the SRF gun and GunLab beam diagnostics, which are now ready for commissioning.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA005

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MOPVA010

Setup and Status of an SRF Photoinjector for Energy-Recovery Linac Applications

865

T. Kamps, D. Böhlick, A.B. Büchel, M. Bürger, P. Echevarria, A. Frahm, F. Göbel, S. Heling, A. Jankowiak, S. Keckert, H. Kirschner, G. Klemz, J. Knobloch, G. Kourkafas, J. Kühn, O. Kugeler, A.N. Matveenko, A. Neumann, N. Ohm-Krafft, E. Panofski, F. Pfloksch, S. Rotterdam, M.A.H. Schmeißer, M. Schuster, H. Stein, J. Ullrich, A. Ushakov, J. Völker
HZB, Berlin, Germany
I. Will
MBI, Berlin, Germany

Funding: The work is funded by the Helmholtz-Association, BMBF, the state of Berlin and HZB.
The Superconducting RF (SRF) photoinjector programme for the energy-recovery linac (ERL) test facility BERLinPro sets out to push the brightness and average current limits for ERL electron sources by tackling the main challenges related to beam dynamics of SRF photoinjectors, the incorporation of high quantum efficiency (QE) photocathodes, and suppression of unwanted beam generation. The paper details the experimental layout of the SRF photoinjector and the gun test facility GunLab at Helmholtz-Zentrum Berlin.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA010

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MOPVA046

120kW RF Power Input Couplers for BERLinPro

960

B.D.S. Hall, V. Dürr, F. Göbel, J. Knobloch, A. Neumann
HZB, Berlin, Germany

The 50-MeV, 100-mA energy-recovery-linac (ERL) demonstration facility BERLinPro is currently undergoing construction at HZB. The high power injection system, that will deliver a beam at 6.5MeV, is split into a 1.4 cell SRF Photo injector and three Cornell-style 2-cell boosters. The injector and two of the booster cavities will provide about 2MeV each and must handle up to 220 kW of beam loading. New, cERL-based 115-kW high power couplers needed for the cavities' twin coupler system have begun manufacture. The design, optimization and manufacturing considerations of these couplers are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA046

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MOPVA049

First Commissioning of an SRF Photo-Injector Module for BERLinPro

971

A. Neumann, A. Burrill, D. Böhlick, A.B. Büchel, M. Bürger, P. Echevarria, A. Frahm, H.-W. Glock, F. Göbel, S. Heling, K. Janke, T. Kamps, S. Keckert, S. Klauke, G. Klemz, J. Knobloch, G. Kourkafas, J. Kühn, O. Kugeler, N. Ohm, E. Panofski, H. Plötz, S. Rotterdam, M. Schenk, M.A.H. Schmeißer, M. Schuster, H. Stein, Y. Tamashevich, J. Ullrich, A. Ushakov, J. Völker
HZB, Berlin, Germany
A. Matheisen, M. Schmökel
DESY, Hamburg, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association.
Helmholtz-Zentrum Berlin (HZB) is currently building an high average current superconducting ERL to demonstrate ERL operation with low normalized beam emittance of 1 mm·mrad at 100mA and short pulses of about 2 ps. For the injector section a series of SRF photoinjector cavities is being developed. The medium power prototype presented here features a 1.4 x λ/2 cell SRF cavity with a normal-conducting, high quantum efficiency CsK2Sb cathode, implementing a modified HZDR-style cathode insert. This injector potentially allows for 6 mA beam current at up to 3.5 MeV kinetic energy. In this contribution, the first RF commissioning results of the photo-injector module will be presented and compared to the level of performance during the cavity production and string assembly process.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA049

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MOPVA053

The SRF Module Developments for BESSY VSR

986

A.V. Vélez, H.-W. Glock, F. Glöckner, B.D.S. Hall, J. Knobloch, A. Neumann, P. Schnizer, E. Sharples, A.V. Tsakanian
HZB, Berlin, Germany

Helmholtz-Zentrum Berlin is developing BESSY VSR, a novel upgrade of the BESSY II facility to provide highly flexible pulse lengths while maintaining the flux and brilliance. The project goal is to simultaneously circulate both standard (some 10 ps long) and short (ps and sub-ps long) pulses offering the BESSY user community picosecond dynamics and high-resolution experiments. The concept relies on the installation of high-voltage SRF cavities operating at the 3rd and 3.5th harmonic whereby the beating of the two frequencies provides RF buckets for long and short bunches. Since these cavities will operate in CW and with high beam current (Ib=300 mA), the cavity design represents a challenging goal. In addition the need to avoid coupled bunch instabilities (CBI's), the installation of the VSR Cryomodule must fit in one of the available 4-m long low beta straights. To address the technological and engineering challenges techniques such as waveguide-damped cavities have been developed. First prototypes have been produced. In this paper, the present SRF developments are presented, including the cavities, high power couplers, higher-order mode absorbers and the cryomodule design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA053

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MOPVA130

Development of Waveguide HOM Loads for BERLinPro and BESSY-VSR SRF Cavities

1160

J. Guo, F. Fors, J. Henry, R.A. Rimmer, H. Wang
JLab, Newport News, Virginia, USA
H.-W. Glock, A. Neumann, A.V. Tsakanian, A.V. Vélez
HZB, Berlin, Germany

Two ongoing accelerator projects at Helmholtz-Zentrum Berlin (HZB), BERLinPro and BESSY-VSR, need to design three different SRF cavities, a 1.3GHz cavity in BERLinPro and 1.5GHz/1.75GHz cavities in BESSY-VSR. These cavities have adopted waveguide HOM dampers in their design, with a few tens of watts HOM power in each load for BERLinPro and a few hundred watts for BESSY-VSR. JLab is collaborating with HZB prototyping these HOM loads. In this paper, we will report on the integrated RF-thermal-mechanical design of the loads, as well as the fabrication and testing results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA130

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TUPAB027

Production, Tuning and Processing Challenges of the BERLinPro Gun1.1 Cavity

1375

H.-W. Glock, A. Frahm, J. Knobloch, A. Neumann
HZB, Berlin, Germany
B. Rosin, D. Trompetter
RI Research Instruments GmbH, Bergisch Gladbach, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of the Helmholtz Association
For the BERLinPro energy recovery LINAC, HZB is developing a superconducting 1.4-cell electron gun, which, in its final version, is planned to be capable of CW 1.3 GHz operation with 77 pC/bunch. For this purpose a series of three superconducting cavities, denoted as Gun 1.0, Gun 1.1 (both designed for 6 mA) and Gun 2.0 (100 mA) are foreseen. Gun 1.0 now reached operational status and the Gun 1.1 cavity is completely manufactured. In the paper the chronology of manufacturing, tuning and processing of the Gun 1.1-cavity is described, also giving details about combined mechanical/electrodynamic simulations, which were performed in order to gain deeper understanding of the cavity's unexpected tuning behavior.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB027

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THPAB095

Detuning Compensation in SC Cavities Using Kalman Filters

3938

A. Ushakov, P. Echevarria, A. Neumann
HZB, Berlin, Germany

For CW driven superconducting cavities operating at small bandwidth, like in ERL or FEL light sources, it is mandatory to precisely control any source of detuning. Therefore, a Kalman [1] filter based approach was developed and implemented as FPGA firmware to act as the core part of a detuning compensation algorithm. It relies on a fit by a second order model to a measured transfer function of cavity's forced oscillations with damping, caused by piezo drives and data about observed current phase with some adjustable confidence rate. The initial data for this core is taken from field detection firmware on mTCA.4's SIS8300-L2 digitizer, transferred by low latency links to a carrier board equipped by piezo drive controller where the DSP processing by the Kalman algorithm performed. The processing is characterized by a 550 kHz rate in pipeline mode and occupies almost all DSP resources of the Spartan 6 FPGA chip. The experimental results of detuning compensating technique applied to a SC photoinjector cavity are presented in this contribution.
Kalman, R. E. (1960): A New Approach to Linear Filtering and Prediction Problems, Transaction of the ASME, Journal of Basic Engineering, Pages 35-45.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB095

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