bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel approach to the control of experimental environments: the ESCA microscopy data-acquisition system at ELETTRA
Authors: Pugliese Roberto , Gregoratti Luca , Krempska Renata , Billè Fulvio , Krempasky Juray , Marsi Marino , Abrami Alessandro
Published: July 2004

An efficient control system is today one of the key points for the successful operation of a beamline at third-generation synchrotron radiation sources. The high cost of these ultra-bright light sources and the limited beam time requires effective instrument handling in order to reduce any waste of measurement time. The basic requirements for such control software are reliability, user-friendliness, modularity, upgradability, as well as the capability of integrating a horde of different instruments, commercial tools and independent pre-existing systems in a possibly distributed environment. A novel approach has been adopted to implement the data-acquisition system of the ESCA microscopy beamline at ELETTRA. The system is based on YASB, a software bus, i.e. an underlying control model to coordinate information exchanges and networking software to implement that model. This `middleware' allows the developer to model applications as a set of interacting agents, i.e. independent software machines. Agents can be implemented using different programming languages and be executed on heterogeneous operating environments, which promotes an effective collaboration between software engineers and experimental physicists.
First results from the crystal structure analysis beamline at SPring-8
Authors: Noda Yukio , Ohshima Ken-ichi , Toraya Hideo , Tanaka Kiyoaki , Terauchi Hikaru , Maeta Hiroshi , Konishi Hiroyuki
Published: July 2004

Results from the first measurements at the crystal structure analysis beamline (BL02B1) at SPring-8 are presented. The capabilities of this beamline are also discussed.
Cryogenic high-resolution X-ray spectrometers for SR-XRF and microanalysis
Authors: Frank M. , Mears C. A. , Labov S. E. , Hiller L. J. , le Grand J. B. , Lindeman M. A. , Netel H. , Chow D. , Barfknecht A. T.
Published: July 2004

Experimental results are presented obtained with a cryogenically cooled high-resolution X-ray spectrometer based on a 141 × 141 µm Nb-Al-Al2O3-Al-Nb superconducting tunnel junction (STJ) detector in an SR-XRF demonstration experiment. STJ detectors can operate at count rates approaching those of semiconductor detectors while still providing a significantly better energy resolution for soft X-rays. By measuring fluorescence X-rays from samples containing transition metals and low-Z elements, an FWHM energy resolution of 6–15 eV for X-rays in the energy range 180–1100 eV has been obtained. The results show that, in the near future, STJ detectors may prove very useful in XRF and microanalysis applications.
Improvement of beamline 4B9A and results of an X-ray diffraction experiment
Authors: Wang D. W. , Jiang H. Y. , Wu Z. H. , Wu X. S. , Jiang S. S. , Yao X. X. , Shao H. M. , Cai Y. M. , Shen L. J. , Wu Z.
Published: July 2004

4B9A is a focusing and monochromatic photon beam at the BSRF, which was constructed in 1990. During the second phase of the BSRF program, the surface of the cylindrical mirror has been coated with Pt, covering the original Ni, and the monochromator has been upgraded. The maximum photon energy extends to 11 keV and the intensity has increased about tenfold with respect to the previous intensity at 6 keV. Synchrotron X-ray diffraction patterns for the Hg-1223 (HgBa2Ca2Cu3O8+δ) superconducting bulk and thin film have been measured at 1.54014 Å. Results indicate that the bulk and film can be indexed as possessing tetragonal symmetry; lattice parameters a = 3.856 Å and c = 15.851 Å for the bulk Hg-1223 compound, and a = 3.8517 Å and c = 15.8511 Å for the film. Their structures are similar.
A compact UHV X-ray diffractometer for studying surfaces and interfaces
Authors: Fujii Yoshikazu , Nakamura Takeshi , Kai Mutsumi , Yoshida Kentaroh
Published: July 2004

A compact ultra-high-vacuum (UHV) X-ray diffractometer for surface glancing X-ray scattering has been constructed. All the equipment, including a rotating-anode source of 18 kW and a UHV specimen chamber, is arranged on one optical table of dimensions 70 × 90 cm. The specimen chamber is 14 cm in diameter and 20 cm high and can be evacuated up to 3 × 10−8 Pa. It is equipped with two Be windows of thicknesses 0.2 and 0.4 mm. Specimen orientation in the vacuum is controlled from the outside. The specimen can be heated up to 773 K. The chamber has two evaporation cells and can be used for in situ observations of growing crystal surfaces. Using this instrument, we observed a mechanically polished Ag surface and successfully made an in situ observation of the layer-by-layer growth of a PbSe(111) surface. The instrument will be useful for preliminary experiments using laboratory sources, prior to final measurements at synchrotron radiation facilities.
Compact synchrotron light source of the HSRC
Authors: Yoshida K. , Takayama T. , Hori T.
Published: July 2004

A 700 MeV synchrotron radiation source optimized in order to be incorporated in the university laboratory is under commissioning at Hiroshima University. The storage ring is of a racetrack type with two long straight sections for installing undulators. The bending field is as strong as 2.7 T, produced by normal-conducting magnet technology, and delivers synchrotron radiation with a critical wavelength of 1.42 nm. The strong magnetic field also enables a low-energy injection scheme to be employed owing to the fast radiation damping. A 150 MeV microtron has been adopted as the injector.
A new UHV angle encoder for high-resolution synchrotron radiation monochromators
Authors: Senf F. , Lammert H. , Follath R. , Zeschke T. , Gudat W. , Feichtinger K. , Fischer P. , Hübner W. , Strobel R.
Published: July 2004

The high precision of 0.1 arcsec required for the positioning of optical elements in new two-axes monochromators at the undulator beamlines at BESSY II has led to the development of UHV-compatible high-precision angle encoders. Mounted directly on the rotation axes, they provide substantial advantages over measuring systems connected outside the vacuum vessel. Making use of a fast closed-loop control system, an accuracy of 0.1 arcsec at a resolution of less than 0.01 arcsec has been experimentally verified.
XAFS and X-MCD spectroscopies with undulator gap scan
Authors: Rogalev Andrei , Gotte Vincent , Goulon Jose´ , Gauthier Christophe , Chavanne Joel , Elleaume Pascal
Published: July 2004

The first experimental applications of the undulator gap-scan technique in X-ray absorption spectroscopy are reported. The key advantage of this method is that during EXAFS scans the undulator is permanently tuned to the maximum of its emission peak in order to maximize the photon statistics. In X-MCD or spin-polarized EXAFS studies with a helical undulator of the Helios type, the polarization rate can also be kept almost constant over a wide energy range.
An electrostrictive drive for fine pitch control in double-crystal monochromators
Authors: Shard A. G. , Dhanak V. R. , Smith A. D.
Published: July 2004

Precise control of the pitch angle of the crystals in a double-crystal monochromator is essential to preserve their accurate alignment while the instrument is scanned. Computer-controlled piezoceramic electrostrictive actuators have recently been installed to the top crystal in two monochromators at the Daresbury SRS to facilitate this. This complements the coarser control provided by the existing stepper motor to give an accurate positioning of the crystal alignment over the full rocking-curve width of the crystals. To maintain accurate alignment during a scan, a number of servo feedback options have been devised. In this paper an analysis of the performance of these drives is presented and their utility in a variety of different experimental techniques is discussed.
Trichromatic Concept at SPring-8 RIKEN Beamline I
Authors: Yamamoto Masaki , Kumasaka Takashi , Fujisawa Tetsuro , Ueki Tatzuo
Published: July 2004

SPring-8 RIKEN beamline I has been designed and developed for structural biology research by the Institute of Physical and Chemical Research (RIKEN). The beamline consists of two experimental stations for protein crystallography and small-angle X-ray scattering. Both types of experiments can be carried out simultaneously, with dichromatic synchrotron radiation emitted from two coaxial undulators with vertical polarization. The branched beams are generated by a transparent diamond crystal. With synchrotron radiation, the multiple-wavelength anomalous-dispersion (MAD) method, which gives phases from a single anomalous scatterer, has been developed. Anomalous scattering contributes a small proportion of the diffraction intensity so that the accuracy of intensity data is important. The protein crystallography branch of RIKEN beamline I has been designed based on a `trichromatic concept' to optimize MAD data collection. This concept requires the quasi-simultaneous collection, by use of a `trichromator', of three intensity data sets at three different wavelengths from a single protein crystal without changing any settings. The main feature of the concept is the minimization of systematic errors in the measurement of anomalous diffraction for the MAD method. Initial commissioning of the beamline has provided three different monochromated undulator beams, which were successfully observed on the phosphor screen located at the near end of the trichromator.
Front-end XY-slits assembly for the SPring-8 undulator beamlines
Authors: Oura M. , Sakurai Y. , Kitamura H.
Published: July 2004

A front-end XY-slits assembly has been designed for the SPring-8 undulator beamlines. This assembly can handle the high heat flux from the undulator, its grazing-incidence L-shaped configuration employing an enhanced heat-transfer technology.
Design of a pre-slit for SPring-8 undulator beamlines
Authors: Takahashi S. , Sakurai Y. , Kitamura H.
Published: July 2004

A volumetric heating method is applied to the pre-slit placed on the SPring-8 standard-undulator beamline front ends in order to handle the very intensive photon beam. A graphite block is used as the radiation-absorbing body, which is brazed to a cooling holder made of oxygen-free high-conductivity copper. Various experiments and calculations have been carried out on the strength of the brazed joint. Comparisons between the experiments and calculations show that static fracture of the joint would not occur even under the highest heat load. The outgassing properties of the graphite blocks are also presented here.
New wiggler beamlines at BSRF
Authors: Tang Esheng , Yan Yonglian , Xia Shaojian , Wang Peiwei , Yi Futing , Huang Yuying , Liu Jin , Cui Mingqi
Published: July 2004

A new multipole wiggler has been installed in the ring of the Beijing Electron Positron Collider (BEPC), and two new beamlines were extracted from it for experiments, including LIGA, microprobe fluorescence analysis, high-pressure diffraction and soft X-ray research. The beam profile and photon intensity were measured and compared with the calculated values. The main parameters and characteristics of the two beamlines are illustrated. Some experimental results are presented.
Experiments with Very High Energy Synchrotron Radiation
Authors: Tschentscher Th. , Suortti P.
Published: July 2004

The use of synchrotron radiation with very high photon energies has become possible only with the latest generation of storage rings. All high-electron-energy synchrotron sources will have a dedicated program for the use of very high photon energies. The high-energy beamline ID15 at the ESRF was the first beamline built and dedicated to this purpose, and it has now been in user operation for more than three years. The useful energy range of this beamline is 30–1000 keV and the superconducting insertion device for producing the highest attainable photon energies is described in detail. The techniques most often used today are diffraction and Compton scattering; an overview of the most important experiments is given. Both techniques have been used in the investigation of magnetic systems, and, additionally, the high resolution in reciprocal space, which can be achieved in diffraction, has led to a series of applications. Other fields of research are addressed, and attempts to indicate possible future research areas of high-energy synchrotron radiation are made.
Components for the X-ray radiometry beamline at BESSY II
Authors: Krumrey M. , Herrmann C. , Müller P. , Ulm G.
Published: July 2004

Optical components for the X-ray radiometry beamline of the Physikalisch-Technische Bundesanstalt at BESSY II were investigated at BESSY I. Reflectometry measurements on different mirror coatings were used to calculate their capability to suppress higher-order radiation. An MgF2 coating proved to be best suited for photon energies below 4 keV. The reflectance of silicon (111) monochromator crystals at low photon energies around 2 keV was homogeneous within ±1%. In a test at a superconducting wavelength shifter the cooling system for the first crystal was shown to cope with the absorbed power of 14 W.
Real-time analysis for MBE by time-resolved core-level photoelectron spectroscopy
Authors: Maeda Fumihiko , Watanabe Yoshio , Oshima Masaharu , Taguchi Masami , Oiwa Retsu
Published: July 2004

A system has been developed for the real-time analysis of surface reactions during molecular beam epitaxial growth which uses photoelectron spectroscopy with VUV light taken from synchrotron radiation. This system consists of a synchrotron radiation beamline and growth/analysis apparatus in which photoelectron spectroscopy is performed with sub-second time resolution. In this system, photoelectron spectra are measured in sequence by a `non-scanning' measurement method that enables the acquisition of snapshot photoelectron spectra using a multi-channel detector. This non-scanning measurement method was enabled by equipping an electric field correction grid. This system was used to monitor the photoelectron spectra of a GaSb(001) surface.
Application of synchrotron radiation to ultrafast spectroscopy
Authors: Nakanishi S. , Itoh H. , Fuji T. , Kashiwagi T. , Tsurumachi N. , Furuichi M. , Nakatsuka H. , Kamada M.
Published: July 2004

A novel application of synchrotron radiation to ultrafast optical spectroscopy is demonstrated. The application is based on the short coherence time of broadband synchrotron radiation and employs a conventional interferometer. From a detailed study of the coherence of synchrotron radiation, it is shown that the coherent interference between two synchrotron radiation beams, split from a single beam, can provide ultimate time resolution down to a few femtoseconds. Experimental results of ultrafast spectroscopy using broadband synchrotron radiation are presented; these include free-induction decay and photon echoes in the visible and ultraviolet regions.
Upgraded IR beamline at UVSOR
Authors: Sakurai M. , Okamura H. , Watanabe M. , Nanba T. , Kimura S. , Kamada M.
Published: July 2004

BL6A1, a far-infrared (FIR) beamline at UVSOR, originally built in 1986, has been recently upgraded. The upgrade included the introduction of a second FT-IR spectrometer, making it possible to cover the entire FIR–IR range (3–10000 cm−1) in one sequence of measurements, without having to open the sample chamber; the beamline has become a more convenient and powerful experimental station than before. The upgrade is also expected to enable such experiments as IR studies of molecules adsorbed on solid surfaces, and time-resolved IR spectroscopies. This paper describes the characteristics of the upgraded BL6A1.
A Pixel-Array Detector for Time-Resolved X-ray Diffraction
Authors: Eikenberry E. F. , Barna S. L. , Tate M. W. , Rossi G. , Wixted R. L. , Sellin P. J. , Gruner S. M.
Published: July 2004

An integrating pixel-array detector for recording time-resolved X-ray diffraction measurements on microsecond timescales has been designed and tested as a 4 × 4 pixel prototype. Operational characteristics and radiation tolerance are discussed. A 100 × 92 array with 151.2 µm square pixels is currently under construction.
Installation of new damped cavities at the Photon Factory storage ring
Authors: Izawa Masaaki , Koseki Tadashi , Sakanaka Shyogo , Takahashi Takeshi , Hass Klaus , Tokumoto Shuichi , Kamiya Yukihide
Published: July 2004

New damped cavities have been installed in the Photon Factory (PF) storage ring and successfully operated in the last scheduled user run of 1996. The new damped cavity is a simple single-cell cavity with somewhat large beam-duct holes. The part of the beam duct that is attached to the cavity is made of SiC, which works as a microwave absorber and damps the higher-order modes excited in the cavity. Because of its simple structure, the operation of the cavity is very stable and also a high power input of more than 150 kW is possible. No coupled-bunch instabilities due to the new cavity were observed during operation.
Effect of the RF cavity temperature on low-energy injection at HLS
Authors: Dai Jianping , Liu Naiquan , Feng Lanlin
Published: July 2004

The resonant frequency shift caused by the temperature of the RF cavity at the Hefei Light Source has been measured and the results analysed. The effect of this frequency shift on low-energy injection with a low cavity voltage is discussed, and a new injection mode is proposed.
Single-pass BPM system of the Photon Factory storage ring
Authors: Honda T. , Katoh M. , Mitsuhashi T. , Ueda A. , Tadano M. , Kobayashi Y.
Published: July 2004

At the 2.5 GeV ring of the Photon Factory, a single-pass beam-position monitor (BPM) system is being prepared for the storage ring and the beam transport line. In the storage ring, the injected beam position during the first several turns can be measured with a single injection pulse. The BPM system has an adequate performance, useful for the commissioning of the new low-emittance lattice. Several stripline BPMs are being installed in the beam transport line. The continuous monitoring of the orbit in the beam transport line will be useful for the stabilization of the injection energy as well as the injection beam orbit.
Operational evaluation of ultrahigh-vacuum protection systems for intense-photon-flux wiggler beamlines
Authors: Kanaya Noriichi , Asaoka Seiji , Sakanaka Shogo , Maezawa Hideki
Published: July 2004

The ultrahigh-vacuum (UHV) protection system at the 2.5 GeV synchrotron radiation source (positron storage ring) at the Photon Factory allows the intense-photon-flux wiggler beamlines to operate safely during synchrotron radiation experiments for a long time. There are six high-power wiggler/undulator beamlines that provide intense photon-flux beams to the experimental hall. In the case of a possible instantaneous vacuum failure at the experimental hall, the intense photon-flux radiation from the wiggler could cause a meltdown of the titanium-alloy fast-closing valve. The authors have developed a UHV protection system. Upon a vacuum failure, the protection system can dump the positron beam by turning off the RF power in the four RF klystrons (150 kW maximum), and then initiate a blade closure of the fast-closing valve. In this paper, the operational performance of the vacuum protection system for the intense-photon-flux wiggler beamlines is evaluated and discussed regarding the actual vacuum deterioration downstream of a beamline at the experimental hall.
Density measurements of liquid under high pressure and high temperature
Authors: Katayama Yoshinori , Tsuji Kazuhiko , Shimomura Osamu , Kikegawa Takumi , Mezouar Mohamed , Martinez-Garcia Domingo , Besson Jean Michel , Häusermann Daniel , Hanfland Michael
Published: July 2004

A new method for density measurements by means of X-ray absorption under high pressure and high temperature using synchrotron radiation has been developed. The method has been modified for a large-volume Paris–Edinburgh press and combined with intense high-energy X-rays at the ESRF. In order to overcome effects of deformation of sample shape under pressure, a ruby cylinder was used as a sample container. The density was determined from the intensity profile of transmitted X-rays. The densities of crystalline and liquid Bi were successfully measured up to 750 K at 1 GPa.
In situ studies of metal–semiconductor interactions with synchrotron radiation
Authors: Sayers D. E. , Goeller P. T. , Boyanov B. I. , Nemanich R. J.
Published: July 2004

The capabilities and performance of a UHV system for in situ studies of metal–semiconductor interactions are described. The UHV system consists of interconnected deposition and analysis chambers, each of which is capable of maintaining a base pressure of approximately 1 × 10−10 torr. The deposited materials and their reaction products can be studied in situ with RHEED, XAFS, AES, XPS, UPS and ARUPS. Results from a study of the reaction of 0.7- and 1.7-monolayer-thick films of cobalt with strained silicon–germanium alloys are presented. The signal-to-noise ratio obtained in these experiments indicates that the apparatus is capable of supporting in situ EXAFS studies of ∼0.1-monolayer-thick films.
A scattering filter for energy-dispersive optics
Authors: Hagelstein Michael , Lienert Ulrich , Ressler Thorsten , San Miguel Alfonso , Freund Andreas , Cunis Sabine , Schulze Clemens , Fontaine Alain , Hodeau Jean-Louis
Published: July 2004

A filtering technique to remove parasitic scattering from X-ray absorption spectra that are acquired in energy-dispersive mode has been developed and tested at the European Synchrotron Radiation Facility. The improved set-up removes small-angle scattering of the sample or the windows of sample cells which may spoil the energy resolution or reduce the intensity of prominent features in the absorption spectrum, such as the white line at the Pt L
III edge. The sample is placed behind the curved monochromator and between two plane perfect crystals in the Bonse–Hart configuration. The dispersion of the Bonse–Hart double-crystal camera is matched to the dispersion of the curved monochromator by inclining the scattering planes of the two optical elements against each other.
Commissioning and first results of the LNLS XAFS beamline
Authors: Tolentino H. , Cezar J. C. , Cruz D. Z. , Compagnon-Cailhol V. , Tamura E. , Martins Alves M. C.
Published: July 2004

An X-ray absorption fine-structure spectroscopy beamline has been installed and commissioned at a bending-magnet source at LNLS. Three monochromators are available: a channel-cut, a double-crystal and a four-crystal set-up. They have been operated from 2500 up to 15000 eV, with a resolving power better than 5500 in the full range. Photon flux of the order of 108 photons s−1 up to 1010 photons s−1 has been attained. The experimental station is equipped with a table that can withstand a weight of 300 kg and track the vertical position of the beam with a 2.5 µm accuracy over a 120 mm stroke. The beamline has been fully characterized and the first results are presented.
High-performance EUV/soft X-ray ellipsometry system using multilayer mirrors
Authors: Kawamura Tomoaki , Delaunay Jean-Jacques , Takenaka, Hisataka , Hayashi Takayoshi , Watanabe Yoshio
Published: July 2004

A high-performance EUV/soft X-ray ellipsometry system using multilayer mirrors has been developed. A couple of multilayer mirrors were used for the polarizer, and two multilayer mirrors were used for the rotating analyser. The multilayer mirrors were optimized to obtain a medium extinction of about 2000. An extinction ratio of the polarizer up to 104 can be achieved by using two multilayer mirrors, and the calculated reflectivity was more than 35%. The calculated error of the optical elements reveals that the error of the polarizer and misalignment optical parts is mainly of the first order, and that of the analyser is of the second order.
Design optimization of a flexural hinge-based bender for X-ray optics
Authors: Zhang L. , Hustache R. , Hignette O. , Ziegler E. , Freund A.
Published: July 2004

This paper presents a parameter study and design optimization of a flexural hinge-based bender by use of finite-element modelling and analytical formulation. The relationship between the mirror shape and the driving forces, the so-called bender driving equation, is established. Various parameters are investigated: the material properties, the geometrical parameters, the stress and deformation of the mirror and flexural hinge, the residual slope error of the mirror, and the resolution required for the actuators. Analysis results have been compared with test results for a prototype bender and a silicon mirror (170 × 40 × 10 mm). Both analysis and test results confirm the microradian accuracy of the bent mirror. Finally, a bender design for short-bending-radius applications is also presented.
Construction and performance test of SGM-TRAIN at UVSOR
Authors: Kamada Masao , Hasumoto Masami , Mizutani Nobuo , Horigome Toshio , Kimura Shin-ichi , Tanaka Shin-ichiro , Sakai Kusuo , Fukui Kazutoshi
Published: July 2004

A new spherical-grating monochromator with translational and rotational assembly including a normal-incidence mount (SGM-TRAIN) has been constructed at BL5A of the UVSOR facility. The SGM-TRAIN is an advanced version of a constant-length SGM with the following improvements: (i) a wide energy range of 5–250 eV; (ii) a high resolving power; (iii) use of linear and circular polarization; (iv) reduction of second-order light; (v) two computer-controlled driving modes. Part of the performance tests are reported along with a detailed description of the design.
Synchrotron Light Sources and Recent Developments of Accelerator Technology
Authors: Kulipanov G. N. , Skrinsky A. N. , Vinokurov N. A.
Published: July 2004

The main aim of the next-generation synchrotron radiation sources is to provide diffraction-limited undulator radiation in the 0.1–4 nm range with an average power of 10–1000 W and monochromaticity of 10−3–10−4. A review of new accelerator technologies that could be used for the construction of such types of synchrotron radiation sources is given.
RF system of the SPring-8 storage ring
Authors: Ego Hiroyasu , Hara Masahiro , Kawashima Yoshitaka , Ohashi Yuji , Ohshima Takashi , Takashima Takeo
Published: July 2004

Construction of three RF stations in the storage ring of SPring-8 has been completed. The design concept concentrates on avoiding a coupled-bunch instability which limits the stored current or makes the synchrotron radiation beam unstable. The cavity is bell-shaped to reduce the coupling impedance of the higher-order modes. The cavity dimensions are trimmed systematically to distribute the higher-order mode frequencies. Each cavity has two movable tuners. The temperature of the cavity cooling water is controlled within 0.02 K and the water flow is kept constant. The construction and commissioning of the SPring-8 storage ring RF system is reported.
Measurement of the electron energy and energy spread at the electron storage ring BESSY I
Authors: Klein R. , Mayer T. , Kuske P. , Thornagel R. , Ulm G.
Published: July 2004

Knowledge of the electron energy with a small uncertainty is necessary for the Physikalisch-Technische Bundesanstalt (PTB) to operate the electron storage ring BESSY I, and the future BESSY II, as a primary radiation source standard of calculable synchrotron radiation. At BESSY I the electron energy can now be measured either by the long-established method of resonant spin depolarization or by the newly set up method of Compton backscattering (CBS) of laser photons (CO2 laser, λ = 10.6 µm). Results obtained at different electron energies by these two independent methods are presented. They agree within a relative uncertainty of better than 10−4. The advantages and disadvantages of these two complementary techniques are described and applications of CBS for the measurement of other storage-ring parameters, e.g. the electron energy spread, are given.
A crowbarless power supply for klystrons
Authors: Kozu H. , Jumonji Y. , Yamazaki C. , Shoji Y. , Hashimoto S. , Ando A.
Published: July 2004

A new crowbarless power supply is to be installed at the New SUBARU storage ring. A high-power switching inverter unit eliminates the need for expensive and unstable crowbar circuits for the klystron power supply. It also realizes a very small voltage ripple in the low-frequency region. This is an important characteristic, especially in a quasi-isochronous storage ring such as New SUBARU.
Construction of 714 MHz HOM-free accelerating cavities
Authors: Sakanaka Shogo , Hinode Fujio , Kubo Kiyoshi , Urakawa Junji
Published: July 2004

A new `higher-order-mode (HOM)-free' accelerating cavity has been developed which can provide an accelerating voltage of more than 400 kV per cavity at a frequency of 714 MHz. The harmful HOMs in the cavities, which can induce beam instabilities at high beam currents, were heavily damped by using four special waveguide ports and broadband microwave loads. Two cavities of this design were installed in the 1.54 GeV accelerator test facility (ATF) damping ring at KEK, and successfully stored beams. This cavity will also be very useful for synchrotron light sources. The basic design, characteristics of HOMs and construction of this cavity are reported.
Position of exit X-rays from rotated-inclined double-crystal monochromators
Authors: Kashihara Yasuharu , Yamazaki Hiroshi , Tamasaku Kenji , Ishikawa Tetsuya
Published: July 2004

The rotated-inclined double-crystal monochromator (RIDCM) has been adopted to reduce the heat load from third-generation undulator radiation. The position of the exit X-rays from RIDCM has been calculated as a function of X-ray energy on the basis of diffraction theory including refraction effects. The results show that the positions of the exit X-rays vary over a wide range due to asymmetric reflection. Methods of fixing the exit position in RIDCM are also discussed.
Laser-induced fluorescence excitation spectroscopy of N2
+ produced by VUV photoionization of N2 and N2O
Authors: Mizutani Masakazu , Niikura Hiromichi , Hiraya Atsunari , Mitsuke Koichiro
Published: July 2004

Synchrotron radiation emitted from the UVSOR storage ring is monochromated by a grazing-incidence monochromator and introduced coaxially with the second harmonic of a mode-locked Ti:sapphire laser. Sample gases, N2 and N2O, are photoionized into vibronically ground N2
+ with the fundamental light of the undulator radiation at 18.0 and 18.6 eV, respectively. Laser-induced fluorescence (LIF) excitation spectra of N2
+ from N2 and N2O are measured in the laser wavelength region of the (B
2Σ
u

+, v′ = 0) ← (X
2Σg
+, v′′ = 0) transition at 389–392 nm. The LIF excitation spectra of N2
+ exhibit two maxima due to the P and R branches in which rotational bands are heavily overlapped. The rotational temperature is determined by simulating an LIF excitation spectrum by using the theoretical intensity distribution of rotation bands convoluted with the spectral width of the laser.
Experimental apparatus for the study of photoabsorption processes of multiply charged ions by synchrotron radiation
Authors: Oura M. , Kojima T. M. , Awaya Y. , Itoh Y. , Kawatsura K. , Kimura M. , Koizumi T. , Sekioka T. , Yamaoka H. , Cox M.
Published: July 2004

Photon–ion merged-beam apparatus using a compact ECR ion source and a high-brilliance light source has been designed for the study of photoabsorption processes of multiply charged ions. Photoion spectroscopy will be performed along isoelectronic, isonuclear and isoionic sequences. The main features of this apparatus are described.
UV emission spectrometer using a non-periodic grating
Authors: Sato H. , Kotsugi T. , Senba S. , Namatame H. , Taniguchi M.
Published: July 2004

A UV emission spectrometer using a non-periodic spherical grating has been designed, which can be attached to the linear or helical undulator beamlines of the HiSOR light source at the Hiroshima Synchrotron Radiation Centre. The useful range of emitted photons from 10 to 100 eV is covered by two gratings with nominal groove spacings of 1/600 and 1/1200 mm. The energy resolution with a 100 µm entrance slit width and the 1/600 mm grating is better than 0.2 eV below 50 eV.
Spectroscopic Techniques using Synchrotron Radiation and Free-Electron and Conventional Lasers
Authors: Tadjeddine A. , Peremans A. , Le Rille A. , Zheng W. Q. , Ortéga J. M. , Glotin F. , Prazeres R. , Meyer M. , Lacoursière J. , Nahon L. , Gisselbrecht M. , Morin P. , Larzillière M. , Marsi M. , Taleb-Ibrahimi A. , Couprie M. E. , Hara T. , Garzella D.
Published: July 2004

Considerable progress in the investigation of the electronic and vibrational properties of atoms, molecules, materials, surfaces and interfaces has been achieved by combining different photon sources of complementary characteristics. In this paper some experimental results obtained recently at LURE by using two synchronized sources, such as the IR free-electron laser (FEL) CLIO, the VUV storage ring FEL, synchrotron radiation and table lasers, are presented. Using CLIO synchronized with a YAG laser allows the investigation of the vibrational properties of adsorbed species by the non-linear optical technique of visible–IR sum (difference) frequency generation, as shown for the adsorption of hydrogen on platinum in the electrochemical environment. The second result reported here relates to the study of the intersubband stimulated emission in GaAs/GaAlAs quantum wells by pump-probe experiments using the two-colour configuration of CLIO. The combination of a mode-locked Ar+ laser and synchrotron radiation has been used for investigations in a pump-probe arrangement of the ionization of Xe atoms via the resonant state Xe* 5p
55d [3/2]1. The final example is a time-resolved core-level spectroscopy study of photoexcited Si(111) 2 × 1 surfaces by using a combination of the naturally synchronized UV storage ring laser and synchrotron radiation.
A high-performance wide-range beamline for elliptically polarized undulator source
Authors: Chung S.-C. , Song Y.-F. , Tseng P.-C. , Chen C.-C. , Chen C. T. , Tsang K.-L.
Published: July 2004

A high-performance wide-range beamline has been designed for monochromatizing circularly polarized photons with energies from 10 to 1400 eV. A grazing SGM-based beamline with two entrance slits has been employed to optimize the performance. The degree of the circular polarization affected by the beamline optics has been analysed. The horizontal and vertical refocusing mirrors have been specially arranged to improve greatly the polarization degree in the low-energy region. By connecting this beamline to a high-efficiency elliptically polarized undulator, this beamline should be able to provide, in the entire energy range, intensive and high-resolution photons of a high degree of circular polarization.
The Advanced Photon Source: Performance and Results from Early Operation
Authors: Moncton David E.
Published: July 2004

The Advanced Photon Source at Argonne National Laboratory is now providing researchers with high-brilliance undulator radiation from below 1 keV to beyond 100 keV. All technical facilities and components are operational and have met design specifications. Fourteen research teams, with responsibility for 40 beamlines on the APS experiment hall floor, are currently installing beamline instrumentation or actively taking data. An overview is presented for the first operational year of the Advanced Photon Source. Emphasis is on the performance of accelerators and insertion devices, as well as early scientific results and future plans.
New high- and low-temperature apparatus for synchrotron polycrystalline X-ray diffraction
Authors: Tang C. C. , Bushnell-Wye G. , Cernik R. J.
Published: July 2004

A high-temperature furnace with an induction heater coil and a cryogenic system based on closed-cycle refrigeration have been assembled to enhance the non-ambient powder diffraction facilities at the Synchrotron Radiation Source, Daresbury Laboratory. The commissioning of the high- and low-temperature devices on the high-resolution powder diffractometer of Station 2.3 is described. The combined temperature range provided by the furnace/cryostat is 10–1500 K. Results from Fe and NH4Br powder samples are presented to demonstrate the operation of the apparatus. The developments presented in this paper are applicable to a wide range of other experiments and diffraction geometries.
Investigation of the phase shift in X-ray forward diffraction using an X-ray interferometer
Authors: Hirano Keiichi , Momose Atsushi
Published: July 2004

The phase shift of forward-diffracted X-rays by a perfect crystal is discussed on the basis of the dynamical theory of X-ray diffraction. By means of a triple Laue-case X-ray interferometer, the phase shift of forward-diffracted X-rays by a silicon crystal in the Bragg geometry was investigated.
A 3 T superconducting magnet for long-run magnetic Compton-scattering experiments
Authors: Sakai Nobuhiko , Ohkubo Hiroshi , Nakamura Yasushi
Published: July 2004

A 3 T superconducting magnet has been designed and constructed for magnetic Compton-profile (MCP) measurements with the new capabilities that the magnetic field direction can be altered quickly (within 5 s) and liquid-He refill is not required for more than one week. For the latter capability, two refrigerators have been directly attached to the cryostat to maintain the low temperature of the radiation shields and for the recondensation of liquid He. The system has been satisfactorily operated for over one week.
An ultrahigh-vacuum goniometer for in situ soft X-ray standing-wave analysis of semiconductor surfaces
Authors: Sugiyama Munehiro , Maeyama Satoshi
Published: July 2004

An ultrahigh-vacuum goniometer was developed for in situ X-ray standing-wave (XSW) analysis of semiconductor surfaces prepared by molecular-beam epitaxy (MBE). Although two ultrahigh-vacuum motors for χ and φ rotating axes are inside the analysis chamber, low-energy photoelectrons can still be collected as the magnetic field is sufficiently suppressed by using metal shields. Furthermore, the sample can be annealed at temperatures higher than 870 K on the goniometer in the analysis chamber. This goniometer is used at beamline 1A (BL-1A) at the Photon Factory, where both monochromated soft X-rays and UV radiation are available. This analysis system was shown to be suitable not only for in situ soft-XSW and X-ray absorption near-edge structure (XANES) studies but also for synchrotron radiation photoelectron spectroscopy (SRPES) studies. The annealing effects on an S-adsorbed GaAs(001) surface could be studied by SRPES, XANES and XSW using this new goniometer.
An ultrahigh-vacuum chamber for surface X-ray diffraction
Authors: Nicklin C. L. , Taylor J. S. G. , Jones N. , Steadman P. , Norris C.
Published: July 2004

An ultrahigh-vacuum environmental chamber for surface X-ray diffraction on Station 9.4 at the Synchrotron Radiation Source, Daresbury Laboratory, is described. Film growth can be monitored by simultaneously recording the Auger signal and the X-ray intensity at a particular point in reciprocal space. Such in situ measurements are essential for understanding the dynamic processes that occur during adsorption. An example is given in which the specularly reflected X-ray signal is correlated with Auger plots, during growth of Tl on Cu(001). In addition, the diffractometer and chamber combination allow large reconstructions to be investigated as shown by the in-plane structural analysis of the c(4×4) InSb surface. A study of the layer structure of Cr on Ag(001), in which an extended out-of-plane detector assembly was used, is also presented.
On a spatially resolving USAXS instrument for operation at a third-generation synchrotron radiation source
Authors: Wilkins Stephen
Published: July 2004

A point-collimation USAXS system based on the Bonse–Hart-diffractometer concept is proposed which takes advantage of a CCD detector to rapidly obtain two-dimensional SAXS data at both high spatial and angular resolution for a line of points on the sample. The method might typically be employed using Bonse–Hart crystal optics in the horizontal plane, encompassing the high-angular-resolution scan direction, and a condensing monochromator in the out-of-diffraction-plane direction as the basis for a pinhole SAXS camera in that plane. The new system is well suited to operation at an undulator beamline on a third-generation synchrotron radiation source. Other applications of the instrument include (i) both absorption and phase-contrast imaging/tomography, (ii) polycrystalline topography, (iii) high-resolution triple-crystal measurements and (iv) diffuse scattering measurements.
Structure changes in the sol–gel systems of hydrated oxides
Authors: Gaponov Yu. A. , Karakchiev L. G. , Lyakhov N. Z. , Tolochko B. P. , Ito K. , Amemiya Y.
Published: July 2004

Sols of hydrated aluminium oxide, hydrated zirconium oxide and their mixtures were investigated during the xerogel–amorphous-product–crystalline-product transition by SAXS using synchrotron radiation. In the different temperature regions certain changes in structure and morphology were observed. Some correlation between the characteristics of the initial sols and their mixtures (the size and shape of the pores) was observed. In the temperature region 298–1173 K the characteristics of the mixed sol are defined by the characteristics of the initial sols.
A practically zero horizontal magnetic field in a planar undulator used in the Tristan Super Light Facility
Authors: Yamamoto Shigeru , Tsuchiya Kimichika , Shioya Tatsuro , Amano Daizo , Sugiyama Hiroshi
Published: July 2004

The Tristan Main Ring (MR) at KEK (High Energy Accelerator Research Organization) has been used as a third-generation synchrotron radiation ring with an undulator installed in the MR as a third-generation light source. The magnetic field irregularities of the undulator were examined precisely. Measurement of the magnetic field after synchrotron radiation experiments showed that the magnetic irregularities in both the horizontal and vertical directions are negligibly small. This result suggests that our previous estimates of emittance, made using the measured undulator spectrum, should correctly represent the properties of the electron beam in the MR.
A superconductive undulator with a period length of 3.8 mm
Authors: Hezel T. , Krevet B. , Moser H. O. , Rossmanith J. A. , Rossmanith R. , Schneider Th.
Published: July 2004

During recent years several attempts have been undertaken to decrease the period length of undulators to the millimetre range. In this paper a novel type of in-vacuum undulator is described which is built using superconductive wires. The period length of this special device is 3.8 mm. In principle, it is possible to decrease this period length even further. A 100-period-long undulator has been built and will be tested with a beam in the near future.
Development of an in-vacuum minipole undulator
Authors: Tanabe Toshiya , Maréchal Xavier-Marie , Tanaka Takashi , Kitamura Hideo , Stefan Peter M.
Published: July 2004

An in-vacuum minipole (short-period) insertion device has been developed in a collaboration between SPring-8 and the National Synchrotron Light Source (NSLS). The magnetic arrays were constructed by SPring-8 and were installed in a chamber with mechanical parts in the X-ray ring (E = 2.584 GeV) at the NSLS in May 1997. The device is made of permanent magnets with 30.5 periods and a period length of 11 mm. It is designed to produce fundamental radiation at 4.6 keV, and, with a modest value of deflection parameter (K = 0.7 at 3.3 mm gap), enables higher harmonics to be used for a variety of experiments.
SPring-8 twin helical undulator
Authors: Hara T. , Tanaka T. , Tanabe T. , Mare´chal X.-M. , Kumagai K. , Kitamura H.
Published: July 2004

There are several ways of producing circularly polarized light, such as using asymmetric devices, crossed undulators etc. The SPring-8 helical undulator introduces a simple way of producing both horizontal and vertical fields in one undulator. All the magnet arrays are arranged above and below the plane of the electron orbit, so there is no limitation of access from the sides of the undulator. For the SPring-8 BL25SU, two helical undulators will be installed in tandem, and the helicity of the polarization can be switched at up to 10 Hz using five kicker magnets.
In-vacuum undulators of SPring-8
Authors: Hara T. , Tanaka T. , Tanabe T. , Maréchal X.-M. , Okada S. , Kitamura H.
Published: July 2004

Most of the SPring-8 insertion devices are in-vacuum undulators except for the soft X-ray devices and one elliptical wiggler. The standard-type SPring-8 in-vacuum undulator has a period of 32 mm and a minimum gap of 8 mm. The fundamental radiation energy ranges from 5.2 to 18.5 keV. Three standard in-vacuum undulators are already installed in the ring and are operating without any problems. The magnetic field correction, the vacuum system and the commissioning of the in-vacuum undulators are described in this paper.
Design of a 2 T multipole wiggler insertion device for the SRS
Authors: Clarke James A. , Bliss Neil , Bradshaw David , Dawson Cheryl , Fell Barry , Harris Neville , Hayes Gary , Poole Michael , Reid Ron
Published: July 2004

Two new identical insertion devices have been designed for the Daresbury SRS. They are 2 T permanent-magnet multipole wigglers that will provide high flux in the X-ray region. This paper describes the magnetic and mechanical design of the arrays of steel pole pieces and permanent-magnet blocks. Also given is the engineering design of the support structure that will cope with the very large forces present while maintaining high levels of precision in gap setting and parallelism. The engineering design has been fully assessed using finite-element techniques to predict the deflections of critical parts of the structure. These two devices are due to be installed into the SRS by the end of 1998.
Effects of magnets with non-unit magnetic permeability on an elliptically polarizing undulator
Authors: Wang Ch. , Chang L. H. , Chang C. H. , Lin M. C. , Hwang C.-S. , Chen J.-R.
Published: July 2004

This study employs the three-dimensional magnetostatic code TOSCA to assess numerically the effects of NdFeB magnets with non-unit magnetic permeability on an elliptically polarizing undulator. A reduction of a few percent of the on-axis magnetic field strength is predicted. In addition, a deviation of ±100 G cm uncompensated dipole steering is predicted in a phase shift of 180° for the elliptically polarizing undulator EPU5.6 (having a period length of 56 mm) at the minimum gap of 18 mm, which is related primarily to the configuration of the device end scheme. Results presented herein demonstrate that implementing an active compensation mechanism is a prerequisite for minimizing the orbit distortion during phase-shift adjustment, particularly for operating such a polarizing undulator in a third-generation machine having a median energy similar to that of the 1.5 GeV storage ring at SRRC.
An SRRC elliptically polarizing undulator prototype to examine mechanical design feasibility and magnetic field performance
Authors: Chang C. H. , Hwang C.-S. , Fan T. C. , Chen K. H. , Pan K. T. , Lin F. Y. , Wang Ch. , Chang L. H. , Chen H. H. , Lin M. C. , Yeh Shuting
Published: July 2004

In this work, a 1 m long Sasaki-type elliptically polarizing undulator (EPU) prototype with 5.6 cm period length is used to examine the mechanical design feasibility as well as magnetic field performance. The magnetic field characteristics of the EPU5.6 prototype at various phase shifts and gap motion are described. The field errors from mechanical tolerances, magnet block errors, end field effects and phase/gap motion effects are analysed. The procedures related to correcting the field with the block position tuning, iron shimming and the trim blocks at both ends are outlined.