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Paper	Title	Other Keywords	Page
MOPPH030	Terahertz Imaging and Radioscopy with 160x120 Microbolometer 90 fps Camera	radiation, free-electron-laser, laser, electron	83
	A. L. Aseev, M. A. Dem'yanenko, D. G. Esaev, I. V. Marchishin ISP, Novosibirsk G. N. Kulipanov, N. Vinokurov, B. A. Knyazev BINP SB RAS, Novosibirsk
	Uncooled micromolometer camera for IR and THz high-speed imaging has been developed. The 160x120 focal plane array consists of resistive vanadium oxide elements on a silicon nitride bridge. The element size is 48x48 micron at 51 micron array period. We describe device fabrication process and focal plane array operational characteristics. The camera was used as a recorder in quasi-optical systems with Novosibirsk terahertz free electron laser as a radiation source. Radioscopy of the objects, which are of interest for biology and security applications, has been demonstrated. The recording rate up to 90 frames per second has been obtained.
MOPPH032	Development of Metal Mesh Based Quasi-optical Selective Components and Their Application in High-power Experiments at Novosibirsk Terahertz FEL	radiation, laser, synchrotron, synchrotron-radiation	89
	B. G. Goldenberg, P. V. Kalinin, V. V. Kubarev, N. Vinokurov, S. A. Kuznetsov BINP SB RAS, Novosibirsk
	Successful realization of terahertz research programs at the Novosibirsk FEL-facility requires detailed development, designing and optimization of passive quasi-optical selective components, intended for polarization and frequency gating of powerful THz-beams of NovoFEL radiation. Along with desired selective characteristics such components should be capable of operating over a long period of time under high-power load conditions (a few hundred Watts of average incident radiation power) without noticeable degradation of their properties. It admits to employ in selective components only low absorbing and thermostable materials, such as high conductivity metals and special types of polymers. This report is devoted to development of metal mesh based selective structures, such as polarizing beamsplitters (attenuators) and different frequency filters, and their application in high-power THz-experiments. Possibilities and prospects of two main production technologies are discussed: 1) conventional photolithography destined for manufacturing thin metal structures deposited on low-absorbing thermostable polymer films; 2) LIGA-technique intended for producing thick substrate-free metal structures.
MOPPH041	Comparative Study of Electro-Optic Effect between Simulation and Measurement	laser, electron, simulation, radiation	104
	J. Y. Huang, C. Kim, I. S. Ko, Y. W. Parc PAL, Pohang, Kyungbuk
	The short, intense, and low emittance electron beams are crucial to make high quality X-ray beam for X-ray free electron laser (XFEL). Electro-Optic Sampling (EOS) is a promising method to measure the electron bunch length non-destructively. A simulation study is done with the pulse propagation method, which utilizes Fourier transform to investigate the evolution of electromagnetic pulse inside the electro-optic (EO) crystal. The experimental result measured with spatial decoding method at Free electron LASer in Hamburg (FLASH) facility in Deutsches Elektronen-Synchrotron (DESY) is analyzed in terms of the relative phase shift between the horizontal and vertical component of the laser pulse. In this report, the experimental results expressed in terms of the "Relative Phase Shift Г" are compared with the simulation result. The simulation and the experimental result show similar values within reasonable error. The way to increase the signal level is also proposed.
MOPPH043	Control and Diagnostic System of Novosibirsk FEL Radiation	radiation, undulator, diagnostics, linac	111
	V. V. Kubarev, E. V. Makashov, K. S. Palagin, S. S. Serednyakov BINP SB RAS, Novosibirsk
	The architecture the main capabilities of control and diagnostic system of the Novosibirsk FEL coherent radiation are described. The client-server model is used for software, controlling this system. The developed software is capable to work both in client and server mode. Also it can control various equipment – from FEL optical cavity mirrors to local equipment of users stations. The mode of control program operation and controlled equipment are determinates by external configuration files. Some results of the system operation are also presented.
WEBAU01	Adaptive 3-D UV-laser Pulse Shaping System to Minimize Emittance for Photocathode RF Gun	laser, emittance, electron, cathode	298
	T. Asaka, H. Dewa, H. Hanaki, T. Kobayashi, A. Mizuno, S. Suzuki, T. Taniuchi, K. Yanagida, H. T. Tomizawa JASRI/SPring-8, Hyogo-ken F. Matsui Industrial Technology Center of Fukui, Fukui City
	We developed an adaptive 3-D shaping (both temporal (1D) and spatial (2D)) short pulse (80 fs~40 ps) UV-laser system as an ideal light source for yearlong stable generation of a low emittance electron beam with a high charge (1~2 nC/pulse). In its current form, the laser’s pulse-energy stability has been improved to 0.2~0.3% (rms; 10 pps, 0.4 TW in femtosecond operation) at the fundamental wavelength and 0.7~1.4% at the third-harmonic generation. Such improvement reflects an ability to stabilize the laser system in a humidity-controlled clean room. The pulse-energy stability of a mode-locked femtosecond oscillator has been continuously held to 0.3% (p-p) for 10 months, 24 hours a day. In addition, the ideal spatial and temporal profiles of a shot-by-shot single UV-laser pulse are essential to suppress emittance growth in an RF gun. We apply a deformable mirror that automatically shapes the spatial UV-laser profile with a feedback routine, based on a genetic algorithm, and a pulse stacker for temporal shaping at the same time. The 3D shape of the laser pulse is spatially top-hat (flattop) and temporally a square stacked pulse. Using a 3D-shaped laser pulse with a diameter of 0.8 mm on the cathode and pulse duration of 10 ps (FWHM), we obtain a minimum normalized emittance of 1.4 π mm mrad with beam energy of 26 MeV.
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WEPPH005	Magnet Sorting for the European XFEL Hybrid Undulator - Comparing Study	undulator, electron, free-electron-laser, laser	326
	B. Faatz, J. Pflueger, Y. Li DESY, Hamburg
	Current permanent magnet material quality is insufficient to obtain field qualities in undulators, which satisfy FEL requirements. Therefore position and orientation of magnets have to be carefully chosen in order to obtain mutual cancellation of field errors. In this paper we compare two different sorting schemes, simulated annealing and a straight forward paring method. They are applied to a 5m prototype structure built for the European XFEL facility. The algorithms of these two methods are described in detail and the sorting results and the expected field qualities are carefully compared.
WEPPH014	Performance of the FERMI FEL Photoinjector Laser	laser, beam-transport, monitoring, cathode	358
	A. A. Demidovich, R. Ivanov, P. Sigalotti, M. B. Danailov ELETTRA, Basovizza, Trieste
	The photoinjector laser system for the FERMI FEL has been installed at the ELETTRA laser laboratory. It is based on a completely CW diode pumping technology and features a two stage pulse shaping system, a time-plate type third harmonic generation scheme and aspheric shaper based beam shaping. The paper will present experimental results describing the overall performance of the amplifier system as well as of the main sub-system listed above. The data demonstrates that all the initially set parameters were met and some largely exceeded. Special attention is dedicated to the pulse shaping allowing both flat-top and increasing ramp UV temporal shapes. A scheme for extraction and shaping of the laser heater pulses using the same laser system is also presented.
WEPPH033	Stabilization of a Klystron Voltage at 100 PPM Level for PAL XFEL	feedback, target, power-supply, klystron	424
	S. D. Jang, S. J. Kwon, Y. G. Son, J.-H. Suh, J.-S. Oh PAL, Pohang, Kyungbuk E. H. Song CNU, Changwon
	The PAL XFEL needs a stable electron beam. The stable charging of PFN (pulse forming network) of a klystron-modulator is essential to provide the stable acceleration field for an electron beam. For PAL XFEL, stabilization of klystron voltage pulses at 100 PPM level is required. Short-term stability is determined by a minimum resolution of a charging system. Long-term stability is determined by a thermal stability due to the temperature drift. This paper shows details of hardware R&D and test results to achieve the target stability.
WEPPH051	Development of a Beam Current Transformer for the X-FEL Project in SPring-8	electron, dumping, klystron, damping	464
	H. Maesaka, Y. Otake, A. Higashiya RIKEN Spring-8 Harima, Hyogo
	The SCSS prototype accelerator has been constructed at SPring-8. The output signal of the current transformer (CT) for measuring an electron beam current in SCSS prototype accelerator has a few megahertz noise emitted from the thyratron of klystron modulator, a ringing signal caused by the weak field of the electron beam. The long period undulation of an electrical ground level at the CT output also occurred by a large electric current generated by the klystron modulator, and flown into the ground. As a result, it is difficult to measure the beam current correctly. Therefore, we devised a new CT monitor in order to improve the problem as mentioned above. The improvement points are below. The thyratron noise was reduced by contacting between the ground of the CT case and the outer surface of a CT signal cable. The ringing signal was suppressed by intercalating dumping resistance material into the space between the case and the ferrite core of CT. We think that the undulation of ground level could be common mode noise and devised how to modulate the undulation. In this paper, we introduce the improvement points, and the obtained waveform of the CT signal as result.
THBAU04	Millimeter Waves Sensing Behind Walls - Feasibility Study with FEL Radiation	radiation, polarization, coupling, survey	501
	M. Einat, M. Kanter, B. Litvak, A. Yahalom, B. Yu. Kapilevich CJS, Ariel A. Gover University of Tel-Aviv, Faculty of Engineering, Tel-Aviv
	The existing through-wall imaging (TWI) systems operate in 1 – 10 GHz, basically, in order to reduce an attenuation caused by building material. However, the spatial resolution is drastically degraded when the operating frequency is relatively low. On the other hand, a majority of building materials demonstrate increased losses as the frequency increases. As a result, higher RF power from the source is required. The Israeli mm-wave FEL provides unique opportunity to solve the above TWI problem permitting to deliver output power 100-1000W at 85-105 GHz. Design of TWI system operating on mm-waves needs comprehensive study of constitutive parameters of different building materials. This paper describes systematic measurements of effective attenuation constant of typical building materials such as concrete bricks, wood, tiles, sand, gypsum, etc. on mm-waves using powerful FEL radiation. Since the Rayleigh criterion for surface roughness cannot be satisfied for some of measured materials, scattering and depolarization effects lead to increasing measured attenuation in comparison with bulky material. Additional experiments were performed to estimate a contribution of these effects into the measured attenuation.
	Slides
FRAAU04	Re-Commissioning of the Far-Infrared Free Electron Laser for Stable and High Power Operation after the Renewal of the L-Band Linac at ISIR, Osaka University	linac, klystron, wiggler, electron	521
	T. Igo, S. Kashiwagi, R. Kato, M. Morio, G. Isoyama ISIR, Osaka
	We have been developing a far-infrared FEL since late 1980s based on the 40 MeV, L-band electron linac at the Institute of Scientific and Industrial Research (ISIR), Osaka University. The first lasing was obtained at 32~40 um in 1994 and since then we progressively modified the FEL system and continued experiment in between to expand the wavelength region toward the longer wavelength. We finally obtained lasing at 150 um in 1998. We could not obtain power saturation because the macropulse duration is 2 us, though the RF pulse is 4 us long, due to a long filling time of the acceleration tube of the L-band linac and the number of amplification times is limited to 50 only. The linac was constructed approximately 30 years ago and it was not suitable for stable and high power operation of FEL, so that we suspended the development of the FEL. In 2002, we had an opportunity to remodel the linac largely for higher stability and reproducibility of operation. We also added a new operation mode for FEL in which the macropulse duration can be extended to 8 us. I took time to remodel the linac and commission it, but finally the operation mode for FEL is being commissioned and we are resuming the FEL again after the long suspension. We will report the progress and the current status of the re-commissioning of the FEL.
	Slides