IPAC2016 - Classification: 02 Photon Sources and Electron Accelerators / A18 Energy Recovery Linacs (ERLs)

Paper	Title	Page
TUPOW032	Modelling of the Short Bunch Optics for BERLinPro	1820
	A. Ginter, A.N. Matveenko HZB, Berlin, Germany
	The Energy Recovery Linac principle allows compressing electron bunches to lengths at least two orders of magnitude shorter compared to storage rings. At BERLinPro bunch compression and decompression can be done in two stages in the injector and main arcs. Starting with different bunch lengths from the gun the distribution of compression between these two stages is subject to optimization. Simulations show that the length and shape of the bunch in the injector and before the linac are the limiting factors for minimal bunch length. Injector simulations have to consider space charge effects, whereas CSR effects are limiting compression in the arcs. The strength of these effects and optimal compression ratios changes with different bunch charges. Optimization and simulation tools have to be chosen according to the energy regime and dominant collective effects. Current status of injector optimization and effect on the compressed bunch are presented.
Export •	reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW033	Status of the BERLinPro Main Linac Module	1823
	H.-W. Glock, A. Frahm, J. Knobloch, A. Neumann HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of the Helmholtz Association Beam operation of the BERLinPro energy recovery linac project, whose construction is under way, will initially start using the photoinjector and booster modules. In a second step the recirculation beam line and the main linac module will be added. Here the current design status of the main linac module is described. Results of wake field simulations are compared for different set ups. We also report on the manufacturing aspects including the design of the waveguide groups needed for HOM damping and the choice of flange-gasket-pairings appropriate for rectangular waveguides. Also mechanical considerations are included.
Export •	reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW034	Status Report of the Berlin Energy Recovery Linac Project BERLinPro	1827
	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. Knobloch, J. Kolbe, G. Kourkafas, J. Kühn, B.C. Kuske, P. 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, J. Rudolph, M. Schmeißer, O. Schüler, M. Schuster, J. Ullrich, A. Ushakov, J. Völker HZB, Berlin, Germany
	Funding: Work supported by the 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 at the Berlin Adlershof site. The project is intended to expand the required accelerator physics and technology knowledge mandatory for the design, construction and operation of future synchrotron light sources. The project goal is the generation of a high current (100 mA), high brilliance (norm. emittance below 1 mm mrad) cw electron beam. We report on the project progress: since spring 2015 the building is under construction, ready for occupancy in January 2017. The planning phase for the first project stage is completed for the warm machine parts, the SRF gun and partly for the SRF booster. Most of the components have been ordered and are in fabrication with some already delivered. An update of the status of the various subprojects as well as a summary of future activities will be given. Project milestones and details of the timeline will be reviewed.
Export •	reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW035	First LLRF Tests of BERLinPro Gun Cavity Prototype	1831
	P. Echevarria, J. Knobloch, O. Kugeler, A. Neumann, A. Ushakov HZB, Berlin, Germany K.P. Przygoda DESY, Hamburg, Germany
	The goal of Berlin Energy Recovery Linac Project (BERLinPro) is the generation of a 50 MeV, 100-mA low emittance (below 1 mm mrad) CW electron beam at 2 ps rms bunch duration or below. Three different types of 1.3 GHz SRF modules will be employed: the electron gun, the booster and the main linac. Precise RF amplitude and phase control are needed due to the beam recovery pro-cess. In this paper we describe the first tests of the Low Level RF control of the first injector prototype at the HoBiCaT facility, implemented in the digital VME-based LLRF controller developed by Cornell University. Tuner movement control by an mTCA.4 system, together with further plans of using this technology will be also presented.
Export •	reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW036	Recent Developments and Operational Status of the Compact ERL at KEK	1835
	T. Obina, M. Adachi, S. Adachi, T. Akagi, M. Akemoto, D.A. Arakawa, S. Araki, S. Asaoka, M. Egi, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X.J. Jin, E. Kako, Y. Kamiya, H. Katagiri, R. Kato, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondo, T. Konomi, A. Kosuge, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, S. Sasaki, K. Satoh, Y. Seimiya, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, N. Terunuma, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, J. Urakawa, K. Watanabe, M. Yamamoto, N. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida KEK, Ibaraki, Japan R. Hajima, M. Mori, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma QST, Tokai, Japan M. Kuriki Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
	The Compact Energy Recovery Linac (cERL) at KEK is a test accelerator in order to develop key components to realize remarkable ERL performance as a future light source. After the beam commissioning in December 2013, the legal current limit has been increased step-by-step like 1 uA, 10 uA, and 100 uA. Survey for the source of beam losses has been conducted in each step, and the study on beam dynamics and tuning has also been carried out. As a next step, 1 mA operation is scheduled in February 2016. In parallel to the increase in beam current, a laser Compton scattering (LCS) system which can provide high-flux X-ray to a beamline has been successfully commissioned. We report recent progress in various kinds of beam tuning: improvement of electron gun performance, high bunch charge operation, mitigation of beam losses, LCS optics tuning and bunch compression for THz radiation.
Export •	reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW038	Measurement and Control of Beam Losses Under High Average-current Operation of the Compact ERL at KEK	1839
	S. Sakanaka, K. Haga, Y. Honda, H. Matsumura, T. Miyajima, T. Nogami, T. Obina, H. Sagehashi, M. Shimada, M. Yamamoto KEK, Ibaraki, Japan
	The compact ERL (cERL)* is a superconducting accelerator aimed at demonstrating excellent ERL technologies for the future light source. The cERL comprises a 5 MeV injector, a main linac, and a recirculation loop. In the cERL, production and transportation of low-emittance and high average-current beams (tentative goals: 1 mm-mrad and 10 mA) is primarily important. At this moment (in December 2015), beam currents of up to 80 uA (CW) have successfully been transported through the recirculation loop at a beam energy of 20 MeV. Before such high-current operations, we carefully tuned up the machine so that beam losses became very small. The beam losses were watched using fast beam-loss detectors and radiation monitors while absolute losses were estimated from measured radiation levels on the roof of the shield. After careful beam-optics corrections and elimination of beam halos / tails at low-energy section, we achieved the beam losses of at most a few nA level at several locations along the loop, and those below 1 nA elsewhere in the loop. We will report these results together with the result of higher-current operation which is planned early in 2016. * S. Sakanaka et al., IPAC'15, TUBC1; T. Obina et al., to be presented at IPAC'16.
Export •	reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW039	Simulation Study of the Beam Halo Formation for Beam Loss Estimation and Mitigation at KEK Compact ERL	1843
	O. Tanaka, T. Miyajima, N. Nakamura, T. Obina, M. Shimada, R. Takai KEK, Ibaraki, Japan
	Funding: Work supported by the "Grant-in-Aid for Creative Scientific Research" of JSPS (KAKENHI 15K04747) At KEK Compact ERL (cERL) we are aiming to produce high-current and low-emittance electron beams (up to 10 mA) without significant beam loss. We believe that beam halo makes a significant impact into the beam loss. Therefore, we are performing beam loss simulations to meet the results of the beam loss measurements. In particular, a simulation of the bunch tail originated from the electron gun was performed to understand the mechanisms of the beam halo formation. Since some measured beam profiles demonstrated unexpected halo particles, several factors such as misalignment of beam line elements and kicks from the steering coils were added into the simulation. Simulation study results are compared with the related beam loss and halo measurements here. Sakanaka et al., these proceedings
Export •	reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW040	UH-FLUX: Compact, Energy Efficient Superconducting Asymmetric Energy Recovery LINAC for Ultra-high Fluxes of X-ray and THz Radiation	1847
	I.V. Konoplev, A. Seryi JAI, Oxford, United Kingdom R. Ainsworth Fermilab, Batavia, Illinois, USA G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
	Funding: This work was supported (in part) by The Leverhulme Trust through the International Network Grant IN-2015-012. The conventional ERLs have limited peak beam current because increasing the beam charge and repetition rate leads to appearance of the beam break-up instabilities. At this stage the highest current, from the SRF ERL, is around 300 mA. A single turn (the beam will be transported through the accelerating section, interaction point and deceleration section of the AERL only once) Asymmetric Energy Recovery LINAC (AERL) is proposed. The RF cells in different sections of the cavity are tuned in such a way that only operating mode is uniform inside all of the cells. The AERL will drive the electron beams with typical energies of 10 - 30 MeV and peak currents above 1 A, enabling the generation of high flux UV/X-rays and high power coherent THz radiation. We aim to build a copper prototype of the RF cavity for a compact AERL to study its EM properties. The final goal is to build AERL based on the superconducting RF cavity. Preliminary design for AERL's cavity has been developed and will be presented. The results of numerical and analytical models and the next steps toward the AERL operation will also be discussed.
Export •	reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Modelling of the Short Bunch Optics for BERLinPro

1820

A. Ginter, A.N. Matveenko
HZB, Berlin, Germany

The Energy Recovery Linac principle allows compressing electron bunches to lengths at least two orders of magnitude shorter compared to storage rings. At BERLinPro bunch compression and decompression can be done in two stages in the injector and main arcs. Starting with different bunch lengths from the gun the distribution of compression between these two stages is subject to optimization. Simulations show that the length and shape of the bunch in the injector and before the linac are the limiting factors for minimal bunch length. Injector simulations have to consider space charge effects, whereas CSR effects are limiting compression in the arcs. The strength of these effects and optimal compression ratios changes with different bunch charges. Optimization and simulation tools have to be chosen according to the energy regime and dominant collective effects. Current status of injector optimization and effect on the compressed bunch are presented.

Export •

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

TUPOW033

Status of the BERLinPro Main Linac Module

1823

H.-W. Glock, A. Frahm, J. Knobloch, A. Neumann
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of the Helmholtz Association
Beam operation of the BERLinPro energy recovery linac project, whose construction is under way, will initially start using the photoinjector and booster modules. In a second step the recirculation beam line and the main linac module will be added. Here the current design status of the main linac module is described. Results of wake field simulations are compared for different set ups. We also report on the manufacturing aspects including the design of the waveguide groups needed for HOM damping and the choice of flange-gasket-pairings appropriate for rectangular waveguides. Also mechanical considerations are included.

Export •

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

TUPOW034

Status Report of the Berlin Energy Recovery Linac Project BERLinPro

1827

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. Knobloch, J. Kolbe, G. Kourkafas, J. Kühn, B.C. Kuske, P. 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, J. Rudolph, M. Schmeißer, O. Schüler, M. Schuster, J. Ullrich, A. Ushakov, J. Völker
HZB, Berlin, Germany

Funding: Work supported by the 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 at the Berlin Adlershof site. The project is intended to expand the required accelerator physics and technology knowledge mandatory for the design, construction and operation of future synchrotron light sources. The project goal is the generation of a high current (100 mA), high brilliance (norm. emittance below 1 mm mrad) cw electron beam. We report on the project progress: since spring 2015 the building is under construction, ready for occupancy in January 2017. The planning phase for the first project stage is completed for the warm machine parts, the SRF gun and partly for the SRF booster. Most of the components have been ordered and are in fabrication with some already delivered. An update of the status of the various subprojects as well as a summary of future activities will be given. Project milestones and details of the timeline will be reviewed.

Export •

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

TUPOW035

First LLRF Tests of BERLinPro Gun Cavity Prototype

1831

P. Echevarria, J. Knobloch, O. Kugeler, A. Neumann, A. Ushakov
HZB, Berlin, Germany
K.P. Przygoda
DESY, Hamburg, Germany

The goal of Berlin Energy Recovery Linac Project (BERLinPro) is the generation of a 50 MeV, 100-mA low emittance (below 1 mm mrad) CW electron beam at 2 ps rms bunch duration or below. Three different types of 1.3 GHz SRF modules will be employed: the electron gun, the booster and the main linac. Precise RF amplitude and phase control are needed due to the beam recovery pro-cess. In this paper we describe the first tests of the Low Level RF control of the first injector prototype at the HoBiCaT facility, implemented in the digital VME-based LLRF controller developed by Cornell University. Tuner movement control by an mTCA.4 system, together with further plans of using this technology will be also presented.

Export •

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

TUPOW036

Recent Developments and Operational Status of the Compact ERL at KEK

1835

T. Obina, M. Adachi, S. Adachi, T. Akagi, M. Akemoto, D.A. Arakawa, S. Araki, S. Asaoka, M. Egi, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X.J. Jin, E. Kako, Y. Kamiya, H. Katagiri, R. Kato, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondo, T. Konomi, A. Kosuge, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, S. Sasaki, K. Satoh, Y. Seimiya, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, N. Terunuma, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, J. Urakawa, K. Watanabe, M. Yamamoto, N. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
KEK, Ibaraki, Japan
R. Hajima, M. Mori, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma
QST, Tokai, Japan
M. Kuriki
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan

The Compact Energy Recovery Linac (cERL) at KEK is a test accelerator in order to develop key components to realize remarkable ERL performance as a future light source. After the beam commissioning in December 2013, the legal current limit has been increased step-by-step like 1 uA, 10 uA, and 100 uA. Survey for the source of beam losses has been conducted in each step, and the study on beam dynamics and tuning has also been carried out. As a next step, 1 mA operation is scheduled in February 2016. In parallel to the increase in beam current, a laser Compton scattering (LCS) system which can provide high-flux X-ray to a beamline has been successfully commissioned. We report recent progress in various kinds of beam tuning: improvement of electron gun performance, high bunch charge operation, mitigation of beam losses, LCS optics tuning and bunch compression for THz radiation.

Export •

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

TUPOW038

Measurement and Control of Beam Losses Under High Average-current Operation of the Compact ERL at KEK

1839

S. Sakanaka, K. Haga, Y. Honda, H. Matsumura, T. Miyajima, T. Nogami, T. Obina, H. Sagehashi, M. Shimada, M. Yamamoto
KEK, Ibaraki, Japan

The compact ERL (cERL)* is a superconducting accelerator aimed at demonstrating excellent ERL technologies for the future light source. The cERL comprises a 5 MeV injector, a main linac, and a recirculation loop. In the cERL, production and transportation of low-emittance and high average-current beams (tentative goals: 1 mm-mrad and 10 mA) is primarily important. At this moment (in December 2015), beam currents of up to 80 uA (CW) have successfully been transported through the recirculation loop at a beam energy of 20 MeV. Before such high-current operations, we carefully tuned up the machine so that beam losses became very small. The beam losses were watched using fast beam-loss detectors and radiation monitors while absolute losses were estimated from measured radiation levels on the roof of the shield. After careful beam-optics corrections and elimination of beam halos / tails at low-energy section, we achieved the beam losses of at most a few nA level at several locations along the loop, and those below 1 nA elsewhere in the loop. We will report these results together with the result of higher-current operation which is planned early in 2016.
* S. Sakanaka et al., IPAC'15, TUBC1; T. Obina et al., to be presented at IPAC'16.

Export •

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

TUPOW039

Simulation Study of the Beam Halo Formation for Beam Loss Estimation and Mitigation at KEK Compact ERL

1843

O. Tanaka, T. Miyajima, N. Nakamura, T. Obina, M. Shimada, R. Takai
KEK, Ibaraki, Japan

Funding: Work supported by the "Grant-in-Aid for Creative Scientific Research" of JSPS (KAKENHI 15K04747)
At KEK Compact ERL (cERL) we are aiming to produce high-current and low-emittance electron beams (up to 10 mA) without significant beam loss. We believe that beam halo makes a significant impact into the beam loss. Therefore, we are performing beam loss simulations to meet the results of the beam loss measurements*. In particular, a simulation of the bunch tail originated from the electron gun was performed to understand the mechanisms of the beam halo formation. Since some measured beam profiles demonstrated unexpected halo particles, several factors such as misalignment of beam line elements and kicks from the steering coils were added into the simulation. Simulation study results are compared with the related beam loss and halo measurements here.
* Sakanaka et al., these proceedings

Export •

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

TUPOW040

UH-FLUX: Compact, Energy Efficient Superconducting Asymmetric Energy Recovery LINAC for Ultra-high Fluxes of X-ray and THz Radiation

1847

I.V. Konoplev, A. Seryi
JAI, Oxford, United Kingdom
R. Ainsworth
Fermilab, Batavia, Illinois, USA
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

Funding: This work was supported (in part) by The Leverhulme Trust through the International Network Grant IN-2015-012.
The conventional ERLs have limited peak beam current because increasing the beam charge and repetition rate leads to appearance of the beam break-up instabilities. At this stage the highest current, from the SRF ERL, is around 300 mA. A single turn (the beam will be transported through the accelerating section, interaction point and deceleration section of the AERL only once) Asymmetric Energy Recovery LINAC (AERL) is proposed. The RF cells in different sections of the cavity are tuned in such a way that only operating mode is uniform inside all of the cells. The AERL will drive the electron beams with typical energies of 10 - 30 MeV and peak currents above 1 A, enabling the generation of high flux UV/X-rays and high power coherent THz radiation. We aim to build a copper prototype of the RF cavity for a compact AERL to study its EM properties. The final goal is to build AERL based on the superconducting RF cavity. Preliminary design for AERL's cavity has been developed and will be presented. The results of numerical and analytical models and the next steps toward the AERL operation will also be discussed.

Export •

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