IPAC2014 - List of Authors (Mueller, A.-S.)

Paper	Title	Page
MOPRO062	Investigating Polarisation and Shape of Beam Microwave Signals at the ANKA Storage Ring	4090
	J. Schwarzkopf, M. Brosi, C. Chang, E. Hertle, V. Judin, B. Kehrer, A.-S. Müller, A.-S. Müller, A.-S. Müller, M. Schuh, M. Schwarz, P. Schönfeldt, P. Schütze, J.L. Steinmann KIT, Karlsruhe, Germany F. Caspers CERN, Geneva, Switzerland
	At the ANKA synchrotron radiation facility measurements in the microwave range (~10 to 12 GHz) employing a LNB (Low Noise Block), which is the receiving part of a Satellite-TV system, have been carried out. Experiments showed that the observed signal depends on the length of the electron bunches. Furthermore the temporal shape of the microwave signal depends on the detector's position along the accelerator. Due the LNB antenna's sensitivity to polarisation it was also possible to measure the polarisation along the several ns long signal, revealing polarised and non-polarised regions. This paper describes the experimental setup and summarises the observations of the systematic studies performed with the LNB system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO062
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MOPRO063	Studies of Bursting CSR in Multi-bunch Operation at the ANKA Storage Ring	225
	V. Judin, M. Brosi, C.M. Caselle, E. Hertle, N. Hiller, A. Kopmann, A.-S. Müller, M. Schuh, N.J. Smale, J.L. Steinmann, M. Weber KIT, Karlsruhe, Germany
	The ANKA storage ring can generate brilliant coherent synchrotron radiation (CSR) in the THz range due to a dedi- cated low-αc -optics with reduced bunch lengths. At higher electron currents the radiation is not stable, but occurs in powerful bursts caused by micro-bunching instabilities. This intense THz radiation is very attractive for users. However, the reproducibility of the experimental conditions is very low due to those power fluctuations. Systematic studies of bursting CSR in multi-bunch operation were performed with fast THz detectors at ANKA using a dedicated, ultra-fast DAQ-FPGA board. The technique and preliminary results of these studies are presented in this paper.
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MOPRO064	An Ultra-low Emittance Model for the ANKA Synchrotron Radiation Source Including Non-linear Effects	228
	A.I. Papash, A.-S. Müller KIT, Eggenstein-Leopoldshafen, Germany E.B. Levichev, P.A. Piminov, S.V. Sinyatkin, K. Zolotarev BINP SB RAS, Novosibirsk, Russia
	An ultra-low emittance lattice based on the ANKA ring geometry is under investigation in framework of the feasibility studies for a compact low emittance synchrotron light source at the Karlsruhe Institute of Technology (Germany). An attempt to apply the concept of split bending magnets cells and to reduce the natural emittance of the bare ANKA DBA lattice from 90 nm×rad down to 2.5 nm×rad with not-vanishing dynamic aperture is described in this paper. The TME cell with split bends and a quadrupole lens in-between as well as a pair of non-interleaved sextupole lenses separated by “I ” unit transfer matrix of betatron oscillations allows to decrease the theoretical minimum emittance of ANKA ring down to approximately 6 nm×rad. Further reduction of the phase space volume requires to brake “I ” symmetry and add extra families of sextupoles, locate an additional high order field elements inside the quadrupoles, optimize the phase advance between sextupole families, shift the betatron tune point, enlarge the sextupole strength and other measures. Results of simulations are reported.
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MOPRO066	Status of FLUTE	231
	M. Schuh, I. Birkel, A. Borysenko, A. Böhm, N. Hiller, E. Huttel, S. Höninger, V. Judin, S. Marsching, A.-S. Müller, A.-S. Müller, A.-S. Müller, S. Naknaimueang, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Schwarz, M. Weber, P. Wesolowski KIT, Eggenstein-Leopoldshafen, Germany R.W. Aßmann, M. Felber, K. Flöttmann, M. Hoffmann, H. Schlarb DESY, Hamburg, Germany H.-H. Braun, R. Ganter, V. Schlott, L. Stingelin PSI, Villigen PSI, Switzerland
	FLUTE, a new linac-based test facility and THz source is currently being built at the Karlsruhe Institute of Technology (KIT) in collaboration with DESY and PSI. It consists of an RF photo gun and a traveling wave linac accelerating electrons to beam energies of ~41 MeV in the charge range from a few pC up to 3 nC. The electron bunch will then be compressed in a magnetic chicane in the range of 1 - 300 fs, depending on the charge, in order to generate coherent THz radiation with high peak power. An overview of the simulation and hardware status is given in this contribution.
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MOPRO067	Analytic Calculation of Electric Fields of Coherent THz Pulses	234
	M. Schwarz, P. Basler, M. Guenther, A.-S. Müller, M. von Borstel KIT, Karlsruhe, Germany M.T. Schmelling MPI-K, Heidelberg, Germany
	The coherently emitted electric field pulse of a short electron bunch is obtained by summing the fields of the individual electrons, taking phase differences due to different longitudinal positions into account. For an electron density, this sum becomes an integral over the charge density and frequency spectrum of the emitted radiation, which, however, is difficult to evaluate numerically. In this paper, we present a fast analytic method valid for arbitrary bunch shapes. We also include shielding effects of the beam pipe and consider ultra-short bunches, where the high frequency part of the coherent synchrotron spectrum is cut-off not by the inverse bunch length but by the critical frequency of synchrotron radiation. Our technique is applied to bunches, simulated simulated for the linac-based FLUTE accelerator test facility at KIT.
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MOPRO068	Fluctuation of Bunch Length in Bursting CSR: Measurement and Simulation	237
	P. Schönfeldt, A. Borysenko, E. Hertle, N. Hiller, V. Judin, A.-S. Müller, S. Naknaimueang, M. Schuh, M. Schwarz, J.L. Steinmann KIT, Karlsruhe, Germany
	The ANKA electron storage ring of the Karlsruher Institute of Technology (KIT, Germany) is regularly operated in low-alpha mode to produce short bunches for the generation of coherent synchrotron radiation (CSR). This paper evaluates systematic bunch length measurements taken in low-alpha operation of the ANKA storage ring. Above the bursting threshold not only the emission of CSR occurs in bursts, but also a continuous fluctuation of the bunch's length is observed. The measurements were carried out using concurrent multi turn (using a streak camera) as well as single shot (using electro-optical spectral decoding) methods. Furthermore, we compare information obtained on the fluctuation to simulations.
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TUZA02	THz Facility at ELBE: A Versatile Test Facility for Electron Bunch Diagnostics on Quasi-CW Electron Beams	933
	M. Gensch, B.W. Green, J. Hauser, S. Kovalev, M. Kuntzsch, U. Lehnert, P. Michel, R. Schurig HZDR, Dresden, Germany A. Al-Shemmary, V. B. Asgekar, T. Golz, H. Schlarb, N. Stojanovic, S. Vilcins DESY, Hamburg, Germany A.S. Fisher SLAC, Menlo Park, California, USA G. Geloni XFEL. EU, Hamburg, Germany A.-S. Müller, M. Schwarz KIT, Karlsruhe, Germany N.E. Neumann, D. Plettemeier TU Dresden, Dresden, Germany
	At the Helmholtz-Zentrum Dresden-Rossendorf near Dresden a quasi-cw low-energy electron linear accelerator based on superconducting radiofrequency technology is operated successfully for more than 10 years. The ELBE accelerator is driving several secondary radiation sources including 2 infrared free electron lasers. A new addition will be a THz facility that aims to make use of super-radiant THz radiation. In its final form the THz facility shall consist of one coherent diffraction radiator and one undulator source which provide high-field THz pulses at unprecedented repetition rates. While the medium term goal is to establish a unique user facility for nonlinear THz science, the THz sources are already used as a test facility for novel diagnostic techniques on quasi-cw electron beams. The progress of the developments is reported and an outlook into future challenges and opportunities is given.
	Slides TUZA02 [3.041 MB]
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TUPME047	SINBAD - A Proposal for a Dedicated Accelerator Research Facility at DESY	1466
	R.W. Aßmann, C. Behrens, R. Brinkmann, U. Dorda, K. Flöttmann, B. Foster, J. Grebenyuk, I. Hartl, M. Hüning, Y.C. Nie, J. Osterhoff, A. Rühl, H. Schlarb, B. Schmidt DESY, Hamburg, Germany M. Groß, B. Marchetti, F. Stephan DESY Zeuthen, Zeuthen, Germany F.J. Grüner, B. Hidding, A.R. Maier Uni HH, Hamburg, Germany F.X. Kärtner, B. Zeitler CFEL, Hamburg, Germany A.-S. Müller, M. Schuh KIT, Karlsruhe, Germany
	A new, dedicated accelerator research facility SINBAD (Short INnovative Bunches and Accelerators at DESY) is proposed. This facility is aimed at promoting two major goals: (1) Short electron bunches for ultra-fast science. (2) Construction of a plasma accelerator module with useable beam quality. Research and development on these topics is presently ongoing at various places at DESY, as add-on experiments at operational facilities. The two research goals are intimately connected: short bunches and precise femtosecond timing are requirements for developing a plasma accelerator module. The scientific case of a dedicated facility for accelerator research at DESY is discussed. Further options are mentioned, like the use of a 1 GeV beam from Linac2 for FEL studies and the setup of an attosecond radiation source with advanced technology. The presently planned conversion of the DORIS storage ring and its central halls into the SINBAD facility is described. The available space will allow setting up several independent experiments with a cost-effective use of the same infrastructure. National and international contributions and proposals can be envisaged.
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TUPRI074	First Results of the New Bunch-by-bunch Feedback System at ANKA	1739
	E. Hertle, N. Hiller, E. Huttel, B. Kehrer, A.-S. Müller, A.-S. Müller, N.J. Smale KIT, Eggenstein-Leopoldshafen, Germany M. Höner DELTA, Dortmund, Germany D. Teytelman Dimtel, San Jose, USA
	A new digital three dimensional fast bunch by bunch feedback system has been installed and commissioned at ANKA. Immediate improvements to stored current and lifetime were achieved for normal user operation. For this, the feedback has to be running during the injection and the energy ramp to 2.5 GeV. Additionally, the feedback system was also incorporated into the diagnostic tool-set at ANKA and opened up new possibilities of automated and continuous measurements of certain beam parameters. The system can operate in different modes such as the low alpha operation mode, which has different requirements on the feedback system compared to normal user operation. Results on the various aspects will be presented as well as future improvements.
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WEOBB02	Status of Single-shot EOSD Measurement at ANKA	1909
	N. Hiller, A. Borysenko, E. Hertle, V. Judin, B. Kehrer, S. Marsching, A.-S. Müller, M.J. Nasse, M. Schuh, P. Schönfeldt, N.J. Smale, J.L. Steinmann KIT, Karlsruhe, Germany P. Peier, B. Steffen DESY, Hamburg, Germany V. Schlott PSI, Villigen PSI, Switzerland
	Funding: This work is funded by the BMBF contract numbers: 05K10VKC, 05K13VKA. ANKA is the first storage ring in the world with a near-field single-shot electro-optical (EO) bunch profile monitor. The method of electro-optical spectral decoding (EOSD) uses the Pockels effect to modulate the longitudinal electron bunch profile onto a long, chirped laser pulse passing through an EO crystal. The laser pulse is then analyzed with a single-shot spectrometer and from the spectral modulation, the temporal modulation can be extracted. The setup has a sub-ps resolution (granularity) and can measure down to bunch lengths of 1.5 ps RMS for bunch charges as low as 30 pC. With this setup it is possible to study longitudinal beam dynamics (e. g. microbunching) occurring during ANKA's low-alpha-operation, an operation mode with compressed bunches to generate coherent synchrotron radiation in the THz range. In addition to measuring the longitudinal bunch profile, long-ranging wake-fields trailing the electron bunch can also be studied, revealing bunch-bunch interactions.
	Slides WEOBB02 [12.753 MB]
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THOBA03	Beam Transport System from a Laser Wakefield Accelerator to a Transverse Gradient Undulator	2803
	C. Widmann, V. Afonso Rodríguez, A. Bernhard, N. Braun, A.-S. Müller, A.I. Papash, R. Rossmanith, W. Werner KIT, Karlsruhe, Germany M. Kaluza, M. Reuter HIJ, Jena, Germany M. Kaluza, M. Nicolai, A. Sävert IOQ, Jena, Germany
	Funding: This work is funded by the German Federal Ministry for Education and Research under contract no. 05K10VK2. The transport and matching of electron beams generated by a laser wakefield accelerator (LWFA) is a major challenge due to their large energy spread and divergence. Strong focussing magnets and a chromatic correction are required. This contribution discusses the layout of the beam transport optics for a diagnostic beamline at the LWFA in Jena, Germany. The aim of this optics is to match the betatron functions and the dispersion to the field of a transverse gradient undulator (TGU) such that monochromatic undulator radiation is generated despite the large energy spread.
	Slides THOBA03 [2.891 MB]
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THPME112	Design of a Compact Setup to Measure Beam Energy by Detection of Compton Backscattered Photons at ANKA	3494
	C. Chang, D. Batchelor, E. Hertle, E. Huttel, V. Judin, A.-S. Müller, A.-S. Müller, A.-S. Müller, M.J. Nasse, M. Schuh, J.L. Steinmann KIT, Karlsruhe, Germany
	Funding: This work is funded by the European Union under contract PITN-GA-2011-289191 One of the most important parameters of accelerators is their beam energy. So far, the method of resonant depolarization was used to accurately determine the energy at 2.5 GeV of the ANKA electron storage ring, which, however, becomes cumbersome for lower energies. A good alternative is the detection of Compton backscattered photons, generated by laser light scattered off the relativistic electron beam. To achieve compactness and integration into the storage ring, the setup of transverse scattering is proposed instead of conventional head-on collision. The feasibility has been studied by comparison between simulations of Compton backscattered photons by AT and CAIN 2.35 and actual measurement of background radiation with an HPGe (High Purity Germanium) spectrometer. The layout of the setup is also included in the paper.
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THPME113	Commissioning of an Ultra-fast Data Acquisition System for Coherent Synchrotron Radiation Detection	3497
	C.M. Caselle, M. Brosi, S.A. Chilingaryan, T. Dritschler, E. Hertle, V. Judin, A. Kopmann, A.-S. Müller, J. Raasch, M. Schleicher, M. Siegel, N.J. Smale, J.L. Steinmann, M. Vogelgesang, M. Weber, S. Wuensch KIT, Karlsruhe, Germany
	The commissioning of a new real-time and high-accuracy data acquisition system suitable for recording individual ultra-short coherent pulses detected by fast terahertz detectors will be presented. The system is able to monitor turn-by-turn all buckets in streaming mode. The main board consists of a direct sampling board operating with a minimum sampling time of 3 psec and a time jitter less than 1.7 psec. The very low noise layout design combined with a wide dynamic range and bandwidth of the analog front-end allows to sample pulse signals generated by various GHz/THz detectors, like NbN and YBCO superconductor film detectors or zero biased Schottky Diode detectors. The digitized data is transmitted to the DAQ system by an FPGA readout board with a data transfer rate of 4 GByte/s. The setup is accomplished by a real-time data processing unit based on high-end graphics processors (GPUs) for on-line analysis of the frequency behaviour of the coherent synchrotron emissions. The system has been successfully used to study the beam properties of the ANKA synchrotron radiation source located at the Karlsruhe Institute of Technology and operating in the energy range between 0.5-2.5 GeV
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THPME123	Electro-optical Bunch Length Monitor for FLUTE: Layout and Simulations	3527
	A. Borysenko, E. Hertle, N. Hiller, V. Judin, B. Kehrer, S. Marsching, A.-S. Müller, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Schuh, M. Schwarz, P. Wesolowski KIT, Karlsruhe, Germany B. Steffen DESY, Hamburg, Germany
	Funding: This work is funded by the European Union under contract PITN-GA-2011-289191 A new compact linear accelerator FLUTE is currently under construction at Karlsruhe Institute of Technology (KIT) in collaboration with DESY and PSI. It aims at obtaining femtosecond electron bunches (~1fs - 300 fs) with a wide charge range (1 pC - 3 nC) and requires a precise bunch length diagnostic system. Here we present the layout of a bunch length monitor based on the electro-optic technique of spectral decoding using an Yb-doped fiber laser system (central wavelength 1030 nm) and a GaP crystal. Simulations of the electro-optic signal for different operation modes of FLUTE were performed and main challenges are discussed in this talk. This work is funded by the European Union under contract PITN-GA-2011-289191
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THPME124	Spectral Analysis of Micro-Bunching Instabilities using Fast THz Detectors	3530
	J.L. Steinmann, E. Hertle, N. Hiller, V. Judin, A.-S. Müller, M. Schuh, P. Schönfeldt, P. Schütze KIT, Karlsruhe, Germany E. Bründermann Ruhr-Universität Bochum, Bochum, Germany
	Micro-bunching instabilities occur at synchrotron light sources when the particle density rises due to compression of the electron bunches. They lead to powerful bursts of coherent synchrotron radiation (CSR) in the THz range at the cost of very unstable intensity and spectral properties, highly fluctuating on a millisecond time scale. For interferometry this changing source demands a long averaging time to achieve a reasonably high signal-to-noise ratio or balancing by the use of an additional reference detector. In this study we present measurements taken by a Martin-Puplett-interferometer in the bursting regime with ultra-fast THz-detectors.
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THPME125	Electrical Field Sensitive High-Tc YBCO Detector for Real-time Observation of CSR	3533
	J. Raasch, K.S. Ilin, Y.-L. Mathis, A.-S. Müller, A. Scheuring, M. Siegel, N.J. Smale, P. Thoma KIT, Karlsruhe, Germany S. Bielawski, C. Evain, E. Roussel, C. Szwaj PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France B. Holzapfel Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany M. Hosaka, N. Yamamoto Nagoya University, Nagoya, Japan K. Iida Leibniz Institute for Solid State and Materials Research Dresden, Dresden, Germany M. Katoh, S.I. Kimura, T. Konomi UVSOR, Okazaki, Japan H. Zen Kyoto University, Kyoto, Japan
	Funding: We thank Agilent Technologies & Tektronix for supplying oscilloscopes. The work was supported by BMBF (05K2010), ANR (2010 blanc 042301), MEXT (Quantum Beam Tech. Prog.), IMS (Int. Collab. Prog.). High-Tc thin-film YBa2Cu3O7-x (YBCO) detectors were deployed for the real-time observation of Coherent Synchrotron Radiation (CSR). Due to enhanced fabrication techniques enabling the patterning of sub-μm sized detector areas responsivity values as high as 1V/pJ for pulsed THz excitations have been achieved at the ANKA synchrotron facility at the Karlsruhe Institute of Technology (KIT). Response of the detectors is linear over the whole dynamic range of the IR1 beamline. Combining the picosecond scaled response mechanism of the high-temperature superconductor YBa2Cu3O7-x (YBCO) to THz excitations with broad-band readout a temporal resolution of 15 ps full width at half maximum (FWHM) was reached. Real-time resolution of CSR single shots was observed at ANKA and UVSOR-III, the synchrotron facility of the Institute of Molecular Science in Okazaki, Japan.
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Paper

Title

Page

Investigating Polarisation and Shape of Beam Microwave Signals at the ANKA Storage Ring

4090

J. Schwarzkopf, M. Brosi, C. Chang, E. Hertle, V. Judin, B. Kehrer, A.-S. Müller, A.-S. Müller, A.-S. Müller, M. Schuh, M. Schwarz, P. Schönfeldt, P. Schütze, J.L. Steinmann
KIT, Karlsruhe, Germany
F. Caspers
CERN, Geneva, Switzerland

At the ANKA synchrotron radiation facility measurements in the microwave range (~10 to 12 GHz) employing a LNB (Low Noise Block), which is the receiving part of a Satellite-TV system, have been carried out. Experiments showed that the observed signal depends on the length of the electron bunches. Furthermore the temporal shape of the microwave signal depends on the detector's position along the accelerator. Due the LNB antenna's sensitivity to polarisation it was also possible to measure the polarisation along the several ns long signal, revealing polarised and non-polarised regions. This paper describes the experimental setup and summarises the observations of the systematic studies performed with the LNB system.

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MOPRO063

Studies of Bursting CSR in Multi-bunch Operation at the ANKA Storage Ring

225

V. Judin, M. Brosi, C.M. Caselle, E. Hertle, N. Hiller, A. Kopmann, A.-S. Müller, M. Schuh, N.J. Smale, J.L. Steinmann, M. Weber
KIT, Karlsruhe, Germany

The ANKA storage ring can generate brilliant coherent synchrotron radiation (CSR) in the THz range due to a dedi- cated low-αc -optics with reduced bunch lengths. At higher electron currents the radiation is not stable, but occurs in powerful bursts caused by micro-bunching instabilities. This intense THz radiation is very attractive for users. However, the reproducibility of the experimental conditions is very low due to those power fluctuations. Systematic studies of bursting CSR in multi-bunch operation were performed with fast THz detectors at ANKA using a dedicated, ultra-fast DAQ-FPGA board. The technique and preliminary results of these studies are presented in this paper.

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MOPRO064

An Ultra-low Emittance Model for the ANKA Synchrotron Radiation Source Including Non-linear Effects

228

A.I. Papash, A.-S. Müller
KIT, Eggenstein-Leopoldshafen, Germany
E.B. Levichev, P.A. Piminov, S.V. Sinyatkin, K. Zolotarev
BINP SB RAS, Novosibirsk, Russia

An ultra-low emittance lattice based on the ANKA ring geometry is under investigation in framework of the feasibility studies for a compact low emittance synchrotron light source at the Karlsruhe Institute of Technology (Germany). An attempt to apply the concept of split bending magnets cells and to reduce the natural emittance of the bare ANKA DBA lattice from 90 nm×rad down to 2.5 nm×rad with not-vanishing dynamic aperture is described in this paper. The TME cell with split bends and a quadrupole lens in-between as well as a pair of non-interleaved sextupole lenses separated by “I ” unit transfer matrix of betatron oscillations allows to decrease the theoretical minimum emittance of ANKA ring down to approximately 6 nm×rad. Further reduction of the phase space volume requires to brake “I ” symmetry and add extra families of sextupoles, locate an additional high order field elements inside the quadrupoles, optimize the phase advance between sextupole families, shift the betatron tune point, enlarge the sextupole strength and other measures. Results of simulations are reported.

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MOPRO066

Status of FLUTE

231

M. Schuh, I. Birkel, A. Borysenko, A. Böhm, N. Hiller, E. Huttel, S. Höninger, V. Judin, S. Marsching, A.-S. Müller, A.-S. Müller, A.-S. Müller, S. Naknaimueang, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Schwarz, M. Weber, P. Wesolowski
KIT, Eggenstein-Leopoldshafen, Germany
R.W. Aßmann, M. Felber, K. Flöttmann, M. Hoffmann, H. Schlarb
DESY, Hamburg, Germany
H.-H. Braun, R. Ganter, V. Schlott, L. Stingelin
PSI, Villigen PSI, Switzerland

FLUTE, a new linac-based test facility and THz source is currently being built at the Karlsruhe Institute of Technology (KIT) in collaboration with DESY and PSI. It consists of an RF photo gun and a traveling wave linac accelerating electrons to beam energies of ~41 MeV in the charge range from a few pC up to 3 nC. The electron bunch will then be compressed in a magnetic chicane in the range of 1 - 300 fs, depending on the charge, in order to generate coherent THz radiation with high peak power. An overview of the simulation and hardware status is given in this contribution.

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MOPRO067

Analytic Calculation of Electric Fields of Coherent THz Pulses

234

M. Schwarz, P. Basler, M. Guenther, A.-S. Müller, M. von Borstel
KIT, Karlsruhe, Germany
M.T. Schmelling
MPI-K, Heidelberg, Germany

The coherently emitted electric field pulse of a short electron bunch is obtained by summing the fields of the individual electrons, taking phase differences due to different longitudinal positions into account. For an electron density, this sum becomes an integral over the charge density and frequency spectrum of the emitted radiation, which, however, is difficult to evaluate numerically. In this paper, we present a fast analytic method valid for arbitrary bunch shapes. We also include shielding effects of the beam pipe and consider ultra-short bunches, where the high frequency part of the coherent synchrotron spectrum is cut-off not by the inverse bunch length but by the critical frequency of synchrotron radiation. Our technique is applied to bunches, simulated simulated for the linac-based FLUTE accelerator test facility at KIT.

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MOPRO068

Fluctuation of Bunch Length in Bursting CSR: Measurement and Simulation

237

P. Schönfeldt, A. Borysenko, E. Hertle, N. Hiller, V. Judin, A.-S. Müller, S. Naknaimueang, M. Schuh, M. Schwarz, J.L. Steinmann
KIT, Karlsruhe, Germany

The ANKA electron storage ring of the Karlsruher Institute of Technology (KIT, Germany) is regularly operated in low-alpha mode to produce short bunches for the generation of coherent synchrotron radiation (CSR). This paper evaluates systematic bunch length measurements taken in low-alpha operation of the ANKA storage ring. Above the bursting threshold not only the emission of CSR occurs in bursts, but also a continuous fluctuation of the bunch's length is observed. The measurements were carried out using concurrent multi turn (using a streak camera) as well as single shot (using electro-optical spectral decoding) methods. Furthermore, we compare information obtained on the fluctuation to simulations.

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TUZA02

THz Facility at ELBE: A Versatile Test Facility for Electron Bunch Diagnostics on Quasi-CW Electron Beams

933

M. Gensch, B.W. Green, J. Hauser, S. Kovalev, M. Kuntzsch, U. Lehnert, P. Michel, R. Schurig
HZDR, Dresden, Germany
A. Al-Shemmary, V. B. Asgekar, T. Golz, H. Schlarb, N. Stojanovic, S. Vilcins
DESY, Hamburg, Germany
A.S. Fisher
SLAC, Menlo Park, California, USA
G. Geloni
XFEL. EU, Hamburg, Germany
A.-S. Müller, M. Schwarz
KIT, Karlsruhe, Germany
N.E. Neumann, D. Plettemeier
TU Dresden, Dresden, Germany

At the Helmholtz-Zentrum Dresden-Rossendorf near Dresden a quasi-cw low-energy electron linear accelerator based on superconducting radiofrequency technology is operated successfully for more than 10 years. The ELBE accelerator is driving several secondary radiation sources including 2 infrared free electron lasers. A new addition will be a THz facility that aims to make use of super-radiant THz radiation. In its final form the THz facility shall consist of one coherent diffraction radiator and one undulator source which provide high-field THz pulses at unprecedented repetition rates. While the medium term goal is to establish a unique user facility for nonlinear THz science, the THz sources are already used as a test facility for novel diagnostic techniques on quasi-cw electron beams. The progress of the developments is reported and an outlook into future challenges and opportunities is given.

Slides TUZA02 [3.041 MB]

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TUPME047

SINBAD - A Proposal for a Dedicated Accelerator Research Facility at DESY

1466

R.W. Aßmann, C. Behrens, R. Brinkmann, U. Dorda, K. Flöttmann, B. Foster, J. Grebenyuk, I. Hartl, M. Hüning, Y.C. Nie, J. Osterhoff, A. Rühl, H. Schlarb, B. Schmidt
DESY, Hamburg, Germany
M. Groß, B. Marchetti, F. Stephan
DESY Zeuthen, Zeuthen, Germany
F.J. Grüner, B. Hidding, A.R. Maier
Uni HH, Hamburg, Germany
F.X. Kärtner, B. Zeitler
CFEL, Hamburg, Germany
A.-S. Müller, M. Schuh
KIT, Karlsruhe, Germany

A new, dedicated accelerator research facility SINBAD (Short INnovative Bunches and Accelerators at DESY) is proposed. This facility is aimed at promoting two major goals: (1) Short electron bunches for ultra-fast science. (2) Construction of a plasma accelerator module with useable beam quality. Research and development on these topics is presently ongoing at various places at DESY, as add-on experiments at operational facilities. The two research goals are intimately connected: short bunches and precise femtosecond timing are requirements for developing a plasma accelerator module. The scientific case of a dedicated facility for accelerator research at DESY is discussed. Further options are mentioned, like the use of a 1 GeV beam from Linac2 for FEL studies and the setup of an attosecond radiation source with advanced technology. The presently planned conversion of the DORIS storage ring and its central halls into the SINBAD facility is described. The available space will allow setting up several independent experiments with a cost-effective use of the same infrastructure. National and international contributions and proposals can be envisaged.

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TUPRI074

First Results of the New Bunch-by-bunch Feedback System at ANKA

1739

E. Hertle, N. Hiller, E. Huttel, B. Kehrer, A.-S. Müller, A.-S. Müller, N.J. Smale
KIT, Eggenstein-Leopoldshafen, Germany
M. Höner
DELTA, Dortmund, Germany
D. Teytelman
Dimtel, San Jose, USA

A new digital three dimensional fast bunch by bunch feedback system has been installed and commissioned at ANKA. Immediate improvements to stored current and lifetime were achieved for normal user operation. For this, the feedback has to be running during the injection and the energy ramp to 2.5 GeV. Additionally, the feedback system was also incorporated into the diagnostic tool-set at ANKA and opened up new possibilities of automated and continuous measurements of certain beam parameters. The system can operate in different modes such as the low alpha operation mode, which has different requirements on the feedback system compared to normal user operation. Results on the various aspects will be presented as well as future improvements.

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WEOBB02

Status of Single-shot EOSD Measurement at ANKA

1909

N. Hiller, A. Borysenko, E. Hertle, V. Judin, B. Kehrer, S. Marsching, A.-S. Müller, M.J. Nasse, M. Schuh, P. Schönfeldt, N.J. Smale, J.L. Steinmann
KIT, Karlsruhe, Germany
P. Peier, B. Steffen
DESY, Hamburg, Germany
V. Schlott
PSI, Villigen PSI, Switzerland

Funding: This work is funded by the BMBF contract numbers: 05K10VKC, 05K13VKA.
ANKA is the first storage ring in the world with a near-field single-shot electro-optical (EO) bunch profile monitor. The method of electro-optical spectral decoding (EOSD) uses the Pockels effect to modulate the longitudinal electron bunch profile onto a long, chirped laser pulse passing through an EO crystal. The laser pulse is then analyzed with a single-shot spectrometer and from the spectral modulation, the temporal modulation can be extracted. The setup has a sub-ps resolution (granularity) and can measure down to bunch lengths of 1.5 ps RMS for bunch charges as low as 30 pC. With this setup it is possible to study longitudinal beam dynamics (e. g. microbunching) occurring during ANKA's low-alpha-operation, an operation mode with compressed bunches to generate coherent synchrotron radiation in the THz range. In addition to measuring the longitudinal bunch profile, long-ranging wake-fields trailing the electron bunch can also be studied, revealing bunch-bunch interactions.

Slides WEOBB02 [12.753 MB]

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THOBA03

Beam Transport System from a Laser Wakefield Accelerator to a Transverse Gradient Undulator

2803

C. Widmann, V. Afonso Rodríguez, A. Bernhard, N. Braun, A.-S. Müller, A.I. Papash, R. Rossmanith, W. Werner
KIT, Karlsruhe, Germany
M. Kaluza, M. Reuter
HIJ, Jena, Germany
M. Kaluza, M. Nicolai, A. Sävert
IOQ, Jena, Germany

Funding: This work is funded by the German Federal Ministry for Education and Research under contract no. 05K10VK2.
The transport and matching of electron beams generated by a laser wakefield accelerator (LWFA) is a major challenge due to their large energy spread and divergence. Strong focussing magnets and a chromatic correction are required. This contribution discusses the layout of the beam transport optics for a diagnostic beamline at the LWFA in Jena, Germany. The aim of this optics is to match the betatron functions and the dispersion to the field of a transverse gradient undulator (TGU) such that monochromatic undulator radiation is generated despite the large energy spread.

Slides THOBA03 [2.891 MB]

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THPME112

Design of a Compact Setup to Measure Beam Energy by Detection of Compton Backscattered Photons at ANKA

3494

C. Chang, D. Batchelor, E. Hertle, E. Huttel, V. Judin, A.-S. Müller, A.-S. Müller, A.-S. Müller, M.J. Nasse, M. Schuh, J.L. Steinmann
KIT, Karlsruhe, Germany

Funding: This work is funded by the European Union under contract PITN-GA-2011-289191
One of the most important parameters of accelerators is their beam energy. So far, the method of resonant depolarization was used to accurately determine the energy at 2.5 GeV of the ANKA electron storage ring, which, however, becomes cumbersome for lower energies. A good alternative is the detection of Compton backscattered photons, generated by laser light scattered off the relativistic electron beam. To achieve compactness and integration into the storage ring, the setup of transverse scattering is proposed instead of conventional head-on collision. The feasibility has been studied by comparison between simulations of Compton backscattered photons by AT and CAIN 2.35 and actual measurement of background radiation with an HPGe (High Purity Germanium) spectrometer. The layout of the setup is also included in the paper.

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THPME113

Commissioning of an Ultra-fast Data Acquisition System for Coherent Synchrotron Radiation Detection

3497

C.M. Caselle, M. Brosi, S.A. Chilingaryan, T. Dritschler, E. Hertle, V. Judin, A. Kopmann, A.-S. Müller, J. Raasch, M. Schleicher, M. Siegel, N.J. Smale, J.L. Steinmann, M. Vogelgesang, M. Weber, S. Wuensch
KIT, Karlsruhe, Germany

The commissioning of a new real-time and high-accuracy data acquisition system suitable for recording individual ultra-short coherent pulses detected by fast terahertz detectors will be presented. The system is able to monitor turn-by-turn all buckets in streaming mode. The main board consists of a direct sampling board operating with a minimum sampling time of 3 psec and a time jitter less than 1.7 psec. The very low noise layout design combined with a wide dynamic range and bandwidth of the analog front-end allows to sample pulse signals generated by various GHz/THz detectors, like NbN and YBCO superconductor film detectors or zero biased Schottky Diode detectors. The digitized data is transmitted to the DAQ system by an FPGA readout board with a data transfer rate of 4 GByte/s. The setup is accomplished by a real-time data processing unit based on high-end graphics processors (GPUs) for on-line analysis of the frequency behaviour of the coherent synchrotron emissions. The system has been successfully used to study the beam properties of the ANKA synchrotron radiation source located at the Karlsruhe Institute of Technology and operating in the energy range between 0.5-2.5 GeV

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THPME123

Electro-optical Bunch Length Monitor for FLUTE: Layout and Simulations

3527

A. Borysenko, E. Hertle, N. Hiller, V. Judin, B. Kehrer, S. Marsching, A.-S. Müller, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Schuh, M. Schwarz, P. Wesolowski
KIT, Karlsruhe, Germany
B. Steffen
DESY, Hamburg, Germany

Funding: This work is funded by the European Union under contract PITN-GA-2011-289191
A new compact linear accelerator FLUTE is currently under construction at Karlsruhe Institute of Technology (KIT) in collaboration with DESY and PSI. It aims at obtaining femtosecond electron bunches (~1fs - 300 fs) with a wide charge range (1 pC - 3 nC) and requires a precise bunch length diagnostic system. Here we present the layout of a bunch length monitor based on the electro-optic technique of spectral decoding using an Yb-doped fiber laser system (central wavelength 1030 nm) and a GaP crystal. Simulations of the electro-optic signal for different operation modes of FLUTE were performed and main challenges are discussed in this talk. This work is funded by the European Union under contract PITN-GA-2011-289191

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THPME124

Spectral Analysis of Micro-Bunching Instabilities using Fast THz Detectors

3530

J.L. Steinmann, E. Hertle, N. Hiller, V. Judin, A.-S. Müller, M. Schuh, P. Schönfeldt, P. Schütze
KIT, Karlsruhe, Germany
E. Bründermann
Ruhr-Universität Bochum, Bochum, Germany

Micro-bunching instabilities occur at synchrotron light sources when the particle density rises due to compression of the electron bunches. They lead to powerful bursts of coherent synchrotron radiation (CSR) in the THz range at the cost of very unstable intensity and spectral properties, highly fluctuating on a millisecond time scale. For interferometry this changing source demands a long averaging time to achieve a reasonably high signal-to-noise ratio or balancing by the use of an additional reference detector. In this study we present measurements taken by a Martin-Puplett-interferometer in the bursting regime with ultra-fast THz-detectors.

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THPME125

Electrical Field Sensitive High-Tc YBCO Detector for Real-time Observation of CSR

3533

J. Raasch, K.S. Ilin, Y.-L. Mathis, A.-S. Müller, A. Scheuring, M. Siegel, N.J. Smale, P. Thoma
KIT, Karlsruhe, Germany
S. Bielawski, C. Evain, E. Roussel, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
B. Holzapfel
Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
M. Hosaka, N. Yamamoto
Nagoya University, Nagoya, Japan
K. Iida
Leibniz Institute for Solid State and Materials Research Dresden, Dresden, Germany
M. Katoh, S.I. Kimura, T. Konomi
UVSOR, Okazaki, Japan
H. Zen
Kyoto University, Kyoto, Japan

Funding: We thank Agilent Technologies & Tektronix for supplying oscilloscopes. The work was supported by BMBF (05K2010), ANR (2010 blanc 042301), MEXT (Quantum Beam Tech. Prog.), IMS (Int. Collab. Prog.).
High-Tc thin-film YBa2Cu3O7-x (YBCO) detectors were deployed for the real-time observation of Coherent Synchrotron Radiation (CSR). Due to enhanced fabrication techniques enabling the patterning of sub-μm sized detector areas responsivity values as high as 1V/pJ for pulsed THz excitations have been achieved at the ANKA synchrotron facility at the Karlsruhe Institute of Technology (KIT). Response of the detectors is linear over the whole dynamic range of the IR1 beamline. Combining the picosecond scaled response mechanism of the high-temperature superconductor YBa2Cu3O7-x (YBCO) to THz excitations with broad-band readout a temporal resolution of 15 ps full width at half maximum (FWHM) was reached. Real-time resolution of CSR single shots was observed at ANKA and UVSOR-III, the synchrotron facility of the Institute of Molecular Science in Okazaki, Japan.

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