bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of the less common hydrogen bonds involving ester oxygen sp
3 atoms as acceptors in the crystal structures of small organic molecules
Authors: Molčanov Krešimir , Kojić-Prodić Biserka , Raos Nenad
Published: July 2004

An analysis of hydrogen bonds involving ester Osp
3 atoms as acceptors has been performed based on the data extracted from the Cambridge Structural Database [Allen (2002). Acta Cryst. B58, 380–388; version 5.25, November 2003], using the ConQuest package to evaluate the stereochemical and electronic properties of the acceptors. Evidence for the existence of this particular type of hydrogen bond and its structural function in crystal packing is presented. Using a cut-off limit on residual indices of R < 0.05 (for the structures with hydrogen bonds involving an oxygen as part of the donor group) and R < 0.085 (for nitrogen as part of the donor group), 230 structures out of the total CSD entries of 298 100 were found to contain hydrogen bonds with the ester Osp
3 atoms as acceptors. The hydrogen-bond donors include water molecules, hydroxyl groups, primary and secondary amines and, in a few cases, imino groups. Four modes of the participation of the ester Osp
3 atoms in hydrogen bonding are detected: as a single acceptor, as a double acceptor, as a single acceptor of a H atom involved in an intermolecular bifurcated hydrogen bond, and as a shared acceptor function with the ester Osp
2 atom in a bifurcated hydrogen bond. The role of such directed noncovalent interactions in crystal packing is demonstrated by a small gallery of selected structures.
A unique high-performance wide-range (10–1500 eV) spherical grating monochromator beamline
Authors: Tseng P.-C. , Chen C.-C. , Dann T.-E. , Chung S.-C. , Chen C. T. , Tsang K.-L.
Published: July 2004

A wide-spectral-range high-performance 6 m-spherical grating monochromator (6 m-SGM) beamline has been designed and is under construction at SRRC. Two different entrance slits, instead of additional mirrors, are used to optimize the overall performance. Six gratings are used to cover photon energies from 10 to 1500 eV. Movable entrance slits and bendable vertical focusing mirrors are used to enhance further the beamline performance. A bendable horizontal focusing mirror is used to improve the resolution and to focus the photon beam at the experimental station immediately after the exit slit. Several end-stations can be installed at the same time to utilize the beam time fully. The expected energy-resolving power, with both slit openings set at 10 µm, is up to 15 000 and 40 000 for the high- and low-energy branches, respectively. A photon flux of 1 × 1011 photons s−1 can be obtained with an energy-resolving power of 20 000.
SCIPE – a simple control interface protocol for experimenters
Authors: Quintana J. P. G.
Published: July 2004

The simple control interface protocol for experimenters (SCIPE) used at Sector 5 of the Advanced Photon Source is presented. This interface provides a generic method for data-acquisition programs to control generic actuators and detectors on a synchrotron beamline. The implementation used by the DuPont–Northwestern–Dow Collaborative Access Team, based on readily available hardware, is also described.
Multi-segmented piezoelectric mirrors as active/adaptive optics components
Authors: Signorato Riccardo , Hignette Olivier , Goulon José
Published: July 2004

The angular acceptance of piezoelectric (Pzt) bimorph mirrors is limited by the maximum length of commercially available Pzt ceramic plates. To overcome this limit and manufacture longer devices, several (2n + 1) 150 mm-long bimorph Pzt stacks were assembled side-to-side. Two prototype mirrors, 450 (n = 1) and 750 (n = 2) mm long, were designed, assembled, polished and optically characterized. They are fully UHV compatible and are now installed in the monochromatic section of the ESRF beamlines ID26 and ID32. Both mirrors cover the full range of required bending radii (1 km concave–3.5 km convex). Junctions between segments do not spoil the optical surface quality. The surface slope error r.m.s. can be kept well below 1 arcsec over the full bending range. Adaptive compensation for low-frequency figure errors was shown to be easy and reliable. After compensation, residual shape errors are of the order of 40 nm r.m.s. over 700 mm.
The ESRF Insertion Devices
Authors: Chavanne Joel , Elleaume Pascal , Van Vaerenbergh Pierre
Published: July 2004

The European Synchrotron Radiation facility is presently operating 47 segments of insertion devices (IDs). A record brilliance of 1 × 1020 photons s−1 (0.1% bandwidth)−1 mm−2 mrad−2 has been reached. Almost all devices are built with permanent magnets with or without iron pole pieces. They have been mechanically and magnetically designed and field-measured in house. Multipole shimming has been applied to all devices to remove the integrated dipole and higher-order multipole fields, thereby reducing the interaction between the IDs and the stored beam. For all undulators, the field errors have been corrected further using spectrum shimming in order to achieve ideal spectral brilliance on all harmonic numbers from 1 to 15. A significant effort has been made to optimize the magnet terminations for both field-integral correction and phasing. A phasing scheme of the undulator segments has been developed which allows the independent manufacture and operation of individual segments. Several designs for undulator phasing are presented, together with a comparison between hybrid and pure-permanent-magnet technology. A new type of variable-polarization helical undulator is presented.
Operational performance of the NIJI-III superconducting storage ring
Authors: Emura Katsuji , Shinzato Tsuyoshi , Tsutsui Yasumitsu , Takada Hiroshi , Noda Nobuo
Published: July 2004

The operational performance of the NIJI-III superconducting storage ring has been studied with particular attention focused on the vacuum performance of the cold-bore chamber. Photon-stimulated gas desorption in the cold-bore chamber was examined after commissioning the storage ring. It was confirmed that the photon-stimulated gas desorption due to diffuse reflection of synchrotron radiation at the absorber was not dominant in the gas desorption when the electron beam was accumulated in the storage ring.
Performance of the VUV beamline 4.1 at the SRS, Daresbury Laboratory
Authors: Dhanak V. R. , Shard A. G. , Muryn C. A. , Wincott P. L. , Thornton G.
Published: July 2004

The performance of a recently commissioned beamline, designated BL4.1, at the SRS, Daresbury Laboratory, is described. This beamline covers the energy range 15 ≥ hυ ≥ 200 eV, using a spherical grating monochromator, and is equipped with a UHV surface-science endstation containing a Scienta SES200 and an HA54 angle-resolving electron-energy analyser. Design parameters and optical specifications are tabulated. Monochromator resolution has been determined by measuring the Fermi edge of a Pt foil cooled to 40 K and these values are compared with the calculated resolution. The flux delivered to the endstation has been measured directly using a calibrated photodiode. The performance of the beamline is further illustrated by reference to a study of the angular distribution of photoemitted intensity from a band-gap state on a TiO2(110) 1 × 2 surface.
Initial results from an in-vacuum undulator in the NSLS X-ray ring
Authors: Stefan P. M. , Tanabe T. , Krinsky S. , Rakowsky G. , Solomon L. , Kitamura H.
Published: July 2004

A short-period in-vacuum undulator for the NSLS X-ray Ring has been developed in a collaboration between SPring-8 and the NSLS, and has achieved its project design goals during commissioning studies. The device is called IVUN (in-vacuum undulator) and employs magnet arrays (31 periods, with an 11 mm period) developed at SPring-8, while the requisite vacuum chamber and mechanical systems were developed at the NSLS. At a magnet gap of 3.3 mm, IVUN produces 4.6 keV radiation in the fundamental, with useful photon fluxes in both the second and third harmonics. The magnet gap is adjustable between 2 and 10 mm. A brief overview of IVUN is presented, together with initial commissioning results: the dependence of electron-beam lifetime and bremsstrahlung on magnet gap, and the output radiation spectrum.
Performance of a helical undulator of the UVSOR
Authors: Kimura Shin-ichi , Kamada Masao , Hama Hiroyuki , Kimura Kazuhiko , Hosaka Masahito , Yamazaki Jun-ichiro , Maréchal X.-M. , Tanaka Takashi , Kitamura Hideo
Published: July 2004

A helical undulator was installed in the 0.75 GeV storage ring of the UVSOR facility of the Institute for Molecular Science. The undulator was designed to produce the fundamental of the circularly polarized undulator radiation in the energy range 2–43 eV, and the higher harmonics with elliptical polarization in the energy range up to 300 eV. Recently, the first spectrum from the undulator was observed. The performance of the undulator and the obtained spectrum are reported.
Measurement of the coherence of synchrotron radiation
Authors: Takayama Y. , Tai R. Z. , Hatano T. , Miyahara T. , Okamoto W. , Kagoshima Y.
Published: July 2004

The first-order spatial (transverse) coherence of synchrotron radiation has been measured using a Young's interferometer at BL28A (a helical-undulator beamline) of the Photon Factory, KEK. The range of the photon energy is about 70–180 eV. The visibility of the fringe was found to depend largely on the electron emittance and the intrinsic photon emittance. In principle, it is possible to gain knowledge of the very small electron emittance, of the order of 10−10 m rad, without disturbing the electron beam in the storage ring.
OPHÉLIE: a variable-polarization electromagnetic undulator optimized for a VUV beamline at Super-ACO
Authors: Nahon L. , Corlier M. , Peaupardin P. , Marteau F. , Marcouillé O. , Alcaraz C.
Published: July 2004

A planar/helical crossed overlapped undulator, called OPHÉLIE, is presented, composed of two identical ten-period (each 25 cm long) crossed undulators whose magnetic fields are produced by electromagnets. Such a design is quite simple, with only one mechanical translational motion, and versatile. After the presentation of the general concept of the crossed undulator and of its actual magnetic design, the expected performances in terms of flux and polarization capabilities are described. It appears that any state of polarization can be produced, at least on the first harmonic, with a large total polarization rate and a potentially high polarization switching frequency.
A magnet model for a hybrid undulator assembly
Authors: Ryynänen Matti
Published: July 2004

A modelling method, in which a single magnet block is divided into several sub-blocks, is described. It is assumed that each sub-block is polarized homogeneously. The sub-block polarizations are derived with a genetic algorithm, which analytically calculates the total magnet flux density values generated by all sub-blocks and fits it to the values measured at the corresponding points in the vicinity of the magnet. The sub-block modellings accomplished show notable improvement in predicting the magnet flux density within the undulator gap when compared with a model based on homogeneously polarized blocks. The sub-block model can also be used when discarding bad magnets from a set. Finally, the results show that the inhomogeneities in individual magnets are one of the major reasons for poor predictability of the undulator field in hybrid devices.
Initial data from the 30-element ORTEC HPGe detector array and the XSPRESS pulse-processing electronics at the SRS, Daresbury Laboratory
Authors: Farrow R. C. , Headspith J. , Dent A. J. , Dobson B. R. , Bilsborrow R. L. , Ramsdale C. A. , Stephenson P. C. , Brierley S. , Derbyshire G. E. , Sangsingkeow P. , Buxton K.
Published: July 2004

Following the completion of the collaborative project between CLRC Daresbury Laboratory and EG&G ORTEC to develop the world's first 30-element HPGe detector for fluorescence XAFS, it has now been tested and commissioned at the SRS. The system was commissioned with the XSPRESS digital pulse-processing electronics and this has demonstrated processed count rates in excess of 10 MHz. Initial data have been recorded and are presented.
Development of Synchrotron Radiation Storage Rings
Authors: Kihara Motohiro
Published: July 2004

Many third-generation light sources have been commissioned over the past ten years, and the soundness of the principal design concepts has been well recognized through experiences at these facilities. Also, technological developments concerning third-generation light sources have been remarkable. With the emittance and current of the beams far exceeding the previous levels, stability requirements of the beams have become much more stringent. In this report the present status of light sources, operational and projected, is summarized, and developments and future prospects of synchrotron radiation storage rings in view of accelerator physics and technology are reviewed.
A dynamic local bump system for producing synchrotron radiation with an alternating elliptical polarization
Authors: Lin K. K. , Hsu K. T. , Chen J. S. , Kuo C. H. , Chen C. S. , Hwu K. H. , Chen J. , Pan K. T. , Wang C. J. , Chen J.-R. , Chen C. T.
Published: July 2004

To facilitate high-sensitivity soft X-ray magnetic circular dichroism experiments, a dynamic local bump system has been developed at the SRRC storage ring. This system was devised to vary dynamically the vertical slope of the electron beam in a bending magnet, producing, in the electron orbit plane, soft X-rays with an alternating elliptical polarization. The local bump was created by using two pairs of vertical correctors located on each side of the bending magnet. The bump strength coefficient was obtained both from calculated estimation and from measured beam-response matrices. Control electronics for proper bump strength settings were designed to incorporate the existing orbit-corrector function. A corresponding graphic user interface was implemented so that the bump amplitude could be easily adjusted. The performance of this system is presented. Disturbance on the stored electron beam orbit was observed while flipping the corrector polarity during EPBM (elliptical polarization from bending magnets) operation. A local feedback loop, developed to eliminate such disturbance on other beamlines, is also described.
Isochronous storage ring of the New SUBARU project
Authors: Ando A. , Amano S. , Hashimoto S. , Kinosita H. , Miyamoto S. , Mochizuki T. , Niibe M. , Shoji Y. , Terasawa M. , Watanabe T. , Kumagai N.
Published: July 2004

The aims of the New SUBARU project are to promote industrial applications in the VUV and soft X-ray region and to develop research and development towards new light sources. The main facility of the New SUBARU project is the 1.5 GeV electron storage ring which is under construction at the SPring-8 site in Harima Science Garden City, Japan. The storage ring is quasi-isochronous and has variable momentum dispersion for the deep study of beam dynamics in very short bunches.
Design of a synchrotron radiation source at Tohoku University
Authors: Katoh Masahiro , Sato Shigeru , Suzuki Shoji , Sugawara Masumi , Watanabe Makoto
Published: July 2004

The construction of a third-generation light source has been proposed at Tohoku University. The emittance is 7.3 nm rad at the nominal beam energy, 1.5 GeV. The circumference is 194 m. The ring consists of 12 double-bend achromatic cells. Ten of 12 dispersion-free long straight sections are 5 m long and will be used for insertion devices and some accelerator components. The remaining two are each 15 m long and reserved for advanced devices, such as a very long undulator or a free-electron laser. A stretcher–booster ring, which is now under commission, will be used as an injector. In total, about 50 beamlines can be constructed and ten of them will be those of insertion devices. The present status of the project is `waiting for approval'.
Suppressing the X–Y coupling effect in compact electron storage rings
Authors: Yamada K. , Hosokawa T.
Published: July 2004

The x–y coupling effect, especially the tilt of the beam profiles, in the Super-ALIS compact electron storage ring has been effectively eliminated. The main feature of this method is the suppression of the most harmful Fourier components of the skew-quadrupole perturbation by using just one thin skew-quadrupole magnet. Therefore, the method should be simple and effective for coupling suppression in compact storage rings that have little space for correction instruments.
New method of Helmholtz coil alignment
Authors: Mizuno Akihiko , Nakamura Naoki , Yoshikawa Hiroshi , Suzuki Shinsuke , Yanagida Kenichi , Hori Toshihiko , Taniuchi Tsutomu , Sakaki Hironao , Yokomizo Hideaki
Published: July 2004

A new alignment method for Helmholtz coils is proposed. This method is based on a probe, whose axis is the same as the alignment axis. This probe includes one magnetic sensor, whose position is slightly shifted from the probe axis, and which is set perpendicular to the axis. Using this probe, the tilt and shift of the magnetic centre of Helmholtz coils can be aligned to within an order of 0.1 mrad and 0.1 mm, respectively. Moreover, by this method, effects of terrestrial magnetism and tilt of the magnetic sensor can be removed from the measurement. This alignment method is presented along with an estimate of the alignment accuracy of the SPring-8 linac injector.
Beam commissioning of the SPring-8 synchrotron
Authors: Suzuki H. , Aoki T. , Tani N. , Fukami K. , Hosoda N. , Kobayashi T. , Hayashi S. , Ohzuchi S. , Tanimoto M. , Okanishi K. , Sasaki T. , Yonehara H.
Published: July 2004

The beam commissioning of the SPring-8 synchrotron was started in December 1996. In the first ten days, the coarse tuning of the pulse magnets for beam injection from the linac, and the excitation pattern of the dipole and the quadrupole magnets, were accomplished during energy ramping of the beam. The acceleration of the beam up to 8 GeV proceeded smoothly. From January to February 1997, the fine-tuning of the synchrotron was continued and the operating parameters of all of the synchrotron equipment were decided.
The Dutch–Belgian beamline at the ESRF
Authors: Borsboom M. , Bras W. , Cerjak I. , Detollenaere D. , Glastra van Loon D. , Goedtkindt P. , Konijnenburg M. , Lassing P. , Levine Y. K. , Munneke B. , Oversluizen M. , van Tol R. , Vlieg E.
Published: July 2004

A brief description is given of the design principles and layout of the Dutch–Belgian beamline at the ESRF. This beamline optimizes the use of the available bending-magnet radiation fan by splitting the beam into two branches, each accommodating two experimental techniques.
A three-dimensional magnetostatics computer code for insertion devices
Authors: Chubar Oleg , Elleaume Pascal , Chavanne Joel
Published: July 2004

RADIA is a three-dimensional magnetostatics computer code optimized for the design of undulators and wigglers. It solves boundary magnetostatics problems with magnetized and current-carrying volumes using the boundary integral approach. The magnetized volumes can be arbitrary polyhedrons with non-linear (iron) or linear anisotropic (permanent magnet) characteristics. The current-carrying elements can be straight or curved blocks with rectangular cross sections. Boundary conditions are simulated by the technique of mirroring. Analytical formulae used for the computation of the field produced by a magnetized volume of a polyhedron shape are detailed. The RADIA code is written in object-oriented C++ and interfaced to Mathematica [Mathematica is a registered trademark of Wolfram Research, Inc.]. The code outperforms currently available finite-element packages with respect to the CPU time of the solver and accuracy of the field integral estimations. An application of the code to the case of a wedge-pole undulator is presented.
Four-crystal camera at BSRF and its applications
Authors: Jiang J. H. , Tian Y. L. , Wang G. L. , Han Y. , Wang Z. G.
Published: July 2004

The four-crystal camera is one of the major items of equipment of the topography station at the Beijing Synchrotron Radiation Facility. The design and some applications of this camera are presented.
Inelastic X-ray scattering in molecular liquids and electron correlation effects
Authors: Hayashi Hisashi , Watanabe Noboru , Udagawa Yasuo
Published: July 2004

Inelastic X-ray scattering spectra of liquid water and cyclohexane have been measured with 2 eV resolution for a momentum transfer range between 0.69 and 2.77 au at BL16A of the Photon Factory, KEK, Tsukuba. Observed spectra are transformed to the dynamic structure factor which is normalized by using the Bethe sum rule, and the static structure factor is obtained. From a comparison with extended CI calculations by the use of various basis sets, correlation effects are proved to be of vital importance in inelastic X-ray scattering.
From First-Order Coherence to Higher-Order Coherence of Synchrotron Radiation
Authors: Miyahara Tsuneaki
Published: July 2004

The difference between first-order and second-order coherence of synchrotron radiation is discussed in relation to how they can be measured and how they affect the noise characteristics of future free-electron lasers.
Advanced field-measurement method with three orthogonal Hall probes for an elliptically polarizing undulator
Authors: Hwang C.-S. , Fan T. C. , Lin F. Y. , Yeh Shuting , Chang C. H. , Chen H. H. , Tseng P. K.
Published: July 2004

A three-orthogonal-Hall-probe assembly with an `on the fly' mapping method has been developed to characterize an elliptically polarizing undulator (EPU). The underlying design concept is that it can measure the three real field components without any field correction under a reliable and synchronization measurement method. Therefore, the relative central position shift, orthogonal angle and the planar Hall effect error between the three Hall probes should be calibrated and readjusted. Experimental results demonstrate that this method can yield an r.m.s. reproducibility of 10 G cm for the three field components and 2 G for the peak field strength. Under precision conditions this system can completely measure the three on-axis field components within 2 min for a 4 m-long EPU.
The PTB electromagnetic undulator for BESSY II
Authors: Klein R. , Bahrdt J. , Herzog D. , Ulm G.
Published: July 2004

The Physikalisch-Technische Bundesanstalt (PTB) will operate an electromagnetic undulator designed for radiometry at the BESSY II storage ring. The undulator has a period length of 180 mm, 21 full periods and a maximum magnetic induction of 0.46 T, resulting in a tuning range of the first harmonic from 5 to 150 eV at 1.7 GeV electron energy. Moreover, the electromagnetic design allows the undulator to be operated in a special mode with the period length doubled to 360 mm, thus accordingly shifting the tuning range to lower energies. The main design parameters of the undulator for radiometric applications, as well as measured magnetic field data, are presented.
Rotating/Helmholtz coil system using a lock-in amplifier method
Authors: Tanabe T. , Kitamura H.
Published: July 2004

Measurement of integrated magnetic induction is an important part of the construction of insertion devices. The so-called `flipping coil system' is normally utilized to characterize the integrated multipole components of the device, a requirement which varies from one storage ring to another. A Helmholtz coil system is used to determine a magnetization vector of each magnet piece in the device. Both systems are designed to measure the integrated magnetic flux to deduce the necessary quantities using the known relationship. We have developed an unconventional system which has a continuously rotating mechanism that allows the use of a lock-in amplifier instead of an integrator or a voltmeter. Detailed descriptions of the equipment are given.
In-vacuum figure-8 undulator for hard X-rays with both horizontal and vertical polarization
Authors: Tanaka Takashi , Maréchal Xavier-Marie , Hara Toru , Tanabe Toshiya , Kitamura Hideo
Published: July 2004

A figure-8 undulator of the in-vacuum type has been adopted as an insertion device for BL24XU, the Hyogo Beamline at SPring-8, to provide hard X-rays with both horizontal and vertical polarization instead of a tandem undulator consisting of horizontal and vertical undulators. The undulator will be operated with the gap almost fixed at 11.6 mm to provide the fundamental radiation with horizontal polarization at 9.5 keV and the 1.5th harmonic with vertical polarization at 14 keV.
An insertion device for the soft X-ray photochemistry beamline at SPring-8
Authors: Tanaka Takashi , Maréchal Xavier-Marie , Hara Toru , Tanabe Toshiya , Kitamura Hideo
Published: July 2004

A figure-8 undulator is an insertion device (ID) proposed at SPring-8 to reduce the heat-load problems encountered with ordinary linear undulators. This device is useful when the K value is high in order to obtain low-energy photons as the fundamental of the undulator radiation. It has therefore been adopted as the ID for the soft X-ray photochemistry beamline (BL27SU) at SPring-8 because linearly polarized photons between 100 and 2000 eV are necessary for the experiments on this beamline. The figure-8 undulator for BL27SU is now under construction and, in the first phase of operation, is expected to cover the energy range down to 500 eV. In the second and third phases, the lowest energy may be reduced to 170 and 100 eV, respectively.
Construction of a vertical undulator at SPring-8
Authors: Tanaka Takashi , Maréchal Xavier-Marie , Hara Toru , Tanabe Toshiya , Kitamura Hideo
Published: July 2004

A new-type insertion device (ID) has been constructed for the structural-biology beamline (BL45XU) at SPring-8. The ID consists of two undulators which can provide vertical polarized radiation (vertical undulators). By changing the individual gap of each undulator independently, photons with two different energies can be obtained. Magnetic field measurements show that the maximum horizontal field is 0.49 T and the magnetic performance is as good as expected.
Insertion devices for BESSY II
Authors: Bahrdt J. , Gaupp A. , Ingold G. , Scheer M. , Gudat W.
Published: July 2004

The high-brilliance synchrotron radiation source BESSY II will provide space for the installation of 14 insertion devices. At the time of writing (July 1997), eight insertion devices are funded. The first light for use by scientists will be available in January 1999. The undulators are designed for a scanning operation in parallel with the monochromator. This modus requires tight tolerances concerning the drive system. The first insertion device to be installed, a U-49 undulator, has been assembled and magnetically measured. The r.m.s. phase error is 2°. An endpole configuration using coils with less than 64 amp-turns makes the angular kick smaller than ±3 µrad over a gap range 15–50 mm.
APS Insertion Devices: Recent Developments and Results
Authors: Gluskin Efim
Published: July 2004

The Advanced Photon Source (APS) now has a total of 23 insertion devices (IDs). Over two-thirds of them are installed on the storage ring. The installed devices include 18, 27 and 55 mm-period undulators; an 85 mm-period wiggler; a 16 cm-period elliptical multipole wiggler; and many 33 mm-period undulators. Most of the IDs occupy storage-ring straight sections equipped with 8 mm vertical-aperture vacuum chambers. All of the IDs were measured magnetically at the APS and, in most cases, underwent a final magnetic tuning in order to minimize variation in the various integrals of the field through the ID over the full gap range. Special shimming techniques to correct magnetic field parameters in appropriate gap-dependent ways were developed and applied. Measurements of the closed-orbit distortion as a function of the ID gap variation have been completed, and results are in a good agreement with magnetic measurements. Spectral diagnostics of the ID radiation, including measurements of the absolute spectral flux, brilliance and polarization, show excellent agreement between calculated and measured results. Studies of the sensitivity of IDs to radiation exposure and measurements of the dose rate received by the IDs are in progress.
Design of a compact synchrotron light source for medical applications at NIRS
Authors: Torikoshi M. , Endo M. , Kumada M. , Noda K. , Yamada S. , Kawachi K.
Published: July 2004

A synchrotron light source dedicated to medical applications is required to be compact for installation in limited spaces at hospitals. The NIRS storage ring, with a circumference of 44.8 m, is designed to accelerate electrons up to 1.8 GeV and to store a beam of 400 mA. The ring is composed of superconducting bending magnets for downsizing. A beam of 300 MeV is injected into the ring from a microtron operated at an L-band RF frequency. There are two superconducting multipole wigglers with nine poles and a maximum field of 8 T, which can produce a photon flux of about 1.4 × 1013 photons s−1 mrad−1 (0.1% bandwidth)−1 at 33 keV used for coronary angiography.
Surface X-ray scattering system at the SRRC
Authors: Hsu Chia-Hung , Tang Mau-Tsu
Published: July 2004

A UHV surface X-ray scattering system has been constructed at the SRRC, providing users with a state-of-the-art system for performing X-ray scattering studies of two-dimensional crystallography, in situ growth mechanisms as well as phase transitions of surfaces and interfaces. A study of the phase transition of the Si(001) reconstructed surface was conducted to commission both the scattering system and the SRRC X-ray beamline. The detailed design and performance of the SRRC surface X-ray scattering system together with the results of the Si(001) study are presented.
High-Resolution X-ray Diffraction of Muscle Using Undulator Radiation from the Tristan Main Ring at KEK
Authors: Wakabayashi Katsuzo , Sugiyama Hiroshi , Yagi Naoto , Irving Thomas C. , Iwamoto Hiroyuki , Horiuti Keisuke , Takezawa Yasunori , Sugimoto Yasunobu , Ogino Masaki , Iino Shigetoki , Kim Duck-Sool , Majima Toshikazu , Amemiya Yoshiyuki , Yamamoto Shigeru , Ando Masami
Published: July 2004

High-resolution X-ray diffraction studies on striated muscle fibres were performed using a hard X-ray undulator installed in the Tristan main ring at KEK, Tsukuba, Japan. The performance of the undulator, along with an example experiment which exploited the unique characteristics of undulator radiation, are reported. The vertical divergence angle of the first harmonic of the undulator was ∼10 µrad under 8 GeV multi-bunch operating conditions and the peak photon flux density was estimated to be ∼3 × 1016 photons s−1 mrad−2 (0.1% bandwidth)−1 (10 mA)−1. The well collimated X-ray beam from the undulator made it possible to resolve clearly, with high angular resolution (∼700 nm), the closely spaced diffraction peaks on the meridional axis in the X-ray patterns arising from the thick filaments of a striated muscle under static conditions. By fitting the meridional intensity pattern, a model for the molecular arrangement of the constituent proteins in the thick filaments is proposed. These studies of muscle demonstrate the promise of undulator radiation from third-generation sources for high-resolution diffraction studies.
Beam-position monitors in the X-ray undulator beamline at PETRA
Authors: Hahn U. , Brefeld W. , Hesse M. , Schneider J. R. , Schulte-Schrepping H. , Seebach M. , Werner M.
Published: July 2004

At the 12 GeV storage ring PETRA, the first synchrotron radiation beamline uses a 4 m-long undulator. The beamline, with a length of 130 m between source and sample, delivers hard X-ray photons usable up to 300 keV. The photon beam has a total power of 7 kW. Combined with the high brilliance, the powerful beam is very critical for all beamline components. Copper, located at a distance of 26 m, hit by the full undulator beam, melts within 20 ms. Different monitors are described for stable, safe and reliable operation of beam and experiments.
High-Resolution High-Count-Rate X-ray Spectroscopy with State-of-the-Art Silicon Detectors
Authors: Strüder L. , Fiorini C. , Gatti E. , Hartmann R. , Holl P. , Krause N. , Lechner P. , Longoni A. , Lutz G. , Kemmer J. , Meidinger N. , Popp M. , Soltau H. , Weber U. , von Zanthier C.
Published: July 2004

For the European X-ray multi-mirror (XMM) satellite mission and the German X-ray satellite ABRIXAS, fully depleted pn-CCDs have been fabricated, enabling high-speed low-noise position-resolving X-ray spectroscopy. The detector was designed and fabricated with a homogeneously sensitive area of 36 cm2. At 150 K it has a noise of 4 e− r.m.s., with a readout time of the total focal plane array of 4 ms. The maximum count rate for single-photon counting was 105 counts s−1 under flat-field conditions. In the integration mode more than 109 counts s−1 can be detected at 6 keV. Its position resolution is of the order of 100 µm. The quantum efficiency is higher than 90% from carbon K X-rays (277 eV) up to 10 keV. New cylindrical silicon drift detectors have been designed, fabricated and tested. They comprise an integrated on-chip amplifier system with continuous reset, on-chip voltage divider, electron accumulation layer stabilizer, large area, homogeneous radiation entrance window and a drain for surface-generated leakage current. At count rates as high as 2 × 106 counts cm−2 s−1, they still show excellent spectroscopic behaviour at room-temperature operation in single-photon detection mode. The energy resolution at room temperature is 220 eV at 6 keV X-ray energy and 140 eV at 253 K, being achieved with Peltier coolers. These systems were operated at synchrotron light sources (ESRF, HASYLAB and NLS) as X-ray fluorescence spectrometers in scanning electron microscopes and as ultra low noise photodiodes. The operation of a multi-channel silicon drift detector system is already foreseen at synchrotron light sources for X-ray holography experiments. All systems are fabricated in planar technology having the detector and amplifiers monolithically integrated on high-resistivity silicon.
Development of 32-channel silicon drift detectors and digital electronics for X-ray spectroscopy
Authors: Gauthier Christophe , Goujon Gerard , Goulon José , Moguiline Eric , Dressler Pierre , Henck Roland , Lampert Marie-Odile
Published: July 2004

The performance of silicon-drift-detector (SDD) arrays and digital electronics designed for X-ray absorption spectroscopy in the fluorescence excitation mode is reported. Different detectors have been manufactured and tested: two single-channel SDDs with different active areas (10 mm2 and 1 cm2) and a monolithic 2 cm2 SDD with eight readout anodes. The energy resolution varies between 160 and 170 eV FWHM. A new digital multichannel shaping amplifier has been produced. Its performance is presented in comparison with that of a standard commercial shaper.
High-accuracy detector calibration in the 3–1500 eV spectral range at the PTB radiometry laboratory
Authors: Scholze Frank , Henneken Heike , Kuschnerus, Peter , Rabus Hans , Richter Mathias , Ulm Gerhard
Published: July 2004

State-of-the-art detector calibration in the UV/VUV and soft X-ray spectral ranges at the Physikalisch-Technische Bundesanstalt (PTB) is based on the primary detector standard SYRES, a cryogenic electrical substitution radiometer capable of measuring radiant power of a few µW. At the PTB radiometry laboratory at the synchrotron radiation facility BESSY, two dedicated beamlines are operated, providing monochromatic radiation of high spectral purity, high radiant power and tunable photon energy in the 3–1500 eV range. The spectral responsivity of detectors, e.g. photodiodes, can be measured with a relative uncertainty of about 1% by direct comparison with SYRES, as will be demonstrated for PtSi/Si and GaAsP/Au Schottky and silicon n-on-p photodiodes. The calibration of photon-counting detectors traceable to SYRES can by accomplished by exploiting the unique capability to scale the spectral photon flux over several orders of magnitude by changing the stored electron current. Calibrations of CCDs and photomultipliers are presented as examples.
A high-temperature environmental chamber for nuclear-resonant Bragg scattering studies
Authors: Zhao J. Y. , Zhang X. W. , Ando M.
Published: July 2004

A compact environmental chamber with a furnace operating in the range from room temperature to about 900 K has been built for a high-temperature nuclear-resonant Bragg scattering study. The compact size (75 mm diameter and 70 mm depth) allows an external magnetic field to be applied from outside permanent Nd–Fe–B alloy magnets; a magnetic field up to 1000 G has been obtained. The chamber can be mounted on a precise θ–2θ goniometer so that in situ observations of X-ray diffraction from a single crystal can be carried out. The temperature is measured by two thermocouples placed at the top and back of the sample and controlled by a PID controller. The temperature fluctuation of the chamber is less than ±1 K.
Instrumentation Developments for X-ray Linear and Circular Dichroism at the ESRF Beamline ID12A
Authors: Goulon José , Rogalev Andrei , Gauthier Christophe , Goulon-Ginet Chantal , Paste Stéphane , Signorato Riccardo , Neumann Claus , Varga Laurence , Malgrange Cécile
Published: July 2004

This paper reports on the performance of the instrumentation developed for the ESRF beamline ID12A, which is dedicated to spectroscopic applications requiring full control of the polarization at energies ≥2.0 keV. Emphasis is placed on the characterization of various optical components of the beamline and on problems associated with either the control or the conversion of the polarization state. A few examples have been selected to illustrate what sort of new spectroscopic information has already been obtained at the beamline. These include the comparison of X-ray magnetic dichroism spectra recorded with linear or circular polarization and the very first detection of X-ray natural circular dichroism in single crystals known to exhibit a very large non-linear susceptibility at optical wavelengths.
Reconstruction for the brilliance-upgrading project of the Photon Factory storage ring
Authors: Katoh M. , Hori Y. , Kobayashi Y. , Sakanaka S. , Izawa M. , Haga K. , Honda T. , Mitsuhashi T. , Obina T. , Pak C. O. , Ohmi K. , Tsuchiya K. , Kanaya N. , Ueda A. , Tadano M. , Takiyama Y. , Asaoka S. , Nogami T. , Shioya T. , Mishina A. , Sato Y. , Tokumoto S. , Takahashi T. , Kasuga T. , Maezawa H. , Kobayashi M. , Kobayakawa H.
Published: July 2004

Reconstruction of the Photon Factory storage ring (PF ring; 2.5 GeV) is now in progress to provide very brilliant synchrotron radiation to users, i.e. the emittance is being reduced by a factor of five. Components, such as the quadrupole and sextupole magnets, vacuum chambers, beamlines and beam-position monitors, are being replaced by new ones in 16 normal-cell sections of the PF ring. The accelerating cavities, injection systems and control systems are also being replaced. Operation will commence when the improvements are completed on 1 October 1997.
High-resolution X-ray topographic images of dislocations in a silicon crystal recorded using an X-ray zooming tube
Authors: Kimura Shigeru , Matsumura Tatsuya , Kinoshita Katsuyuki , Hirano Keiichi , Kihara Hiroshi
Published: July 2004

A Be-window-type X-ray zooming tube is an X-ray digital imaging system whose magnification factor of X-ray images can be easily varied from 10 to 200, and whose spatial resolution is less than 0.5 µm. This zooming tube was used as an imaging detector in double-crystal X-ray topography to obtain high-resolution images of dislocations in a silicon crystal. X-ray interference images of about 5 µm were observed even though optimal performance of the X-ray zooming tube could not be achieved. The results indicate that the X-ray zooming tube might make a good detector for X-ray topography with minor improvements in its stage structure.
Submicrometre-area high-energy-resolution photoelectron spectroscopy system
Authors: Kiyokura Takanori , Maeda Fumihiko , Watanabe Yoshio , Shigemasa Eiji , Yagishita Akira , Oshima Masaharu , Iketaki Yoshinori , Horikawa Yoshiaki
Published: July 2004

A submicrometre-area photoelectron spectroscopy system that uses a multi-layer-coated Schwarzschild objective as the soft X-ray microbeam optics has been developed. The system is located at an undulator beamline (BL-16U) at the Photon Factory in the High Energy Accelerator Research Organization. By knife-edge measurement, the microbeam size was estimated to be 160 nm at the sample position using a 25–75% criterion. Photoelectron spectral measurements revealed that the Fermi edge width was 0.12 eV, which means that the instrumental resolution was 0.05 eV, after removing the natural broadening of the Fermi edge at room temperature. This system offers both high energy resolution and high spatial resolution.
Phase-Contrast Tomographic Imaging Using an X-ray Interferometer
Authors: Momose Atsushi , Takeda Tohoru , Itai Yuji , Yoneyama Akio , Hirano Keiichi
Published: July 2004

Apparatus for phase-contrast X-ray computed tomography using a monolithic X-ray interferometer is presented with some observational results for human breast tissues. Structures characteristic of the tissues were revealed in the phase-contrast tomograms. The procedure of image analysis consists of phase retrieval from X-ray interference patterns and tomographic image reconstruction from the retrieved phase shift. Next, feasibility of phase-contrast imaging using a two-crystal X-ray interferometer was studied aiming at in vivo observation in the future. In a preliminary study, the two-crystal X-ray interferometer was capable of generating fringes of 70% visibility using synchrotron X-rays.
Development of scanning X-ray microscopes for materials science spectromicroscopy at the Advanced Light Source
Authors: Warwick T. , Ade H. , Cerasari S. , Denlinger J. , Franck K. , Garcia A. , Hayakawa S. , Hitchcock A. , Kikuma J. , Klingler S. , Kortright J. , Morisson G. , Moronne M. , Rightor E. , Rotenberg, E. , Seal S. , Shin H.-J. , Steele W. F. , Tonner B. P.
Published: July 2004

The development of two zone-plate microscopes for X-ray spectroscopic analysis of materials is described. This pair of instruments will provide imaging NEXAFS analysis of samples in transmission at atmospheric pressure and imaging XPS and NEXAFS analysis of sample surfaces in a UHV environment.
Activities of optical laboratories 1 and 2 at the Photon Factory
Authors: Mitsuhashi Toshiyuki , Hiramatsu Sigenori , Takeuchi Naoya , Itoh Masahide , Yatagai Toyohiko
Published: July 2004

Recent activities at optical laboratories 1 and 2 at the Photon Factory are presented. The activities are (i) construction of optical laboratory 1, (ii) reconstruction of optical laboratory 2, (iii) construction of a visible synchrotron radiation beam extraction mirror made of beryllium, (iv) small-beam-profile measurement by means of the image restoration method, (v) application of the adaptive optical system for correction of distorted wavefronts caused by deformation of the extraction mirror, (vi) construction of a synchrotron radiation interferometer for investigation of the spatial coherency of the visible synchrotron radiation beam and its application to the measurement of vertical beam profile and size.
Pump and probe X-ray absorption fine structure using high-brilliance photon sources
Authors: Oyanagi H. , Kolobov A. , Tanaka K.
Published: July 2004

Pump and probe X-ray absorption fine structure (XAFS) is used as a local probe of excited atoms, which can provide direct information on lattice distortion, relaxation and atomic rearrangements associated with electronic excitations. In situ XAFS experiments during optical excitation are reported. Utilizing a grazing-incidence fluorescence excitation, which minimizes the mismatch between the probing depths of X-ray excitation and optical pumping, it is found that the dominant photoinduced defect state in amorphous selenium at low temperature is a pair of threefold neutral C^0_3 states: 2C^*_2 \rightarrow (C^0_3-C^0_3), where C^*_2 denotes the twofold excited lone-pair state. The results indicate that optical pumping of chalcogen atoms at low temperature leads to locally over-coordinated defect pairs similar to those in the liquid state. The origin of reversible photostructural changes, such as photodarkening or photoinduced fluidity, is attributed to the structural disorder caused by the formation and annihilation of dynamical interchain bonds during optical melting.
Sample-angle feedback for diffraction anomalous fine-structure spectroscopy
Authors: Cross J. O. , Elam W. T. , Harris V. G. , Kirkland J. P. , Bouldin C. E. , Sorensen L. B.
Published: July 2004

Diffraction anomalous fine-structure (DAFS) experiments measure Bragg peak intensities as continuous functions of photon energy near a core-level excitation. Measuring the integrated intensity at each energy makes the experiments prohibitively slow; however, in many cases DAFS can be collected quickly by measuring only the peak intensity at the center of the rocking curve. A piezoelectric-actuator-driven stage has been designed and tested as part of a sample-angle feedback circuit for locking onto the maximum of the rocking curve while the energy is scanned. Although software peak-tracking requires only a simple calculation of diffractometer angles, it is found that the additional hardware feedback dramatically improves the reproducibility of the data.
SPring-8 in-vacuum undulator beam test at the ESRF
Authors: Hara T. , Tanaka T. , Tanabe T. , Maréchal X.-M. , Kitamura H. , Elleaume P. , Morrison B. , Chavanne J. , Van Vaerenbergh P. , Schmidt D.
Published: July 2004

Before the commissioning of SPring-8, the in-vacuum hybrid undulator developed at SPring-8 had been brought to the ESRF for the first beam test in the summer of 1996. The purpose of this test was to investigate the influence of the in-vacuum undulator on the beam and check its vacuum system. However, heating by the resistive wall impedance turned out to be a critical issue for the in-vacuum undulators.
New beam-position monitor system for upgraded Photon Factory storage ring
Authors: Haga K. , Honda T. , Tadano M. , Obina T. , Kasuga T.
Published: July 2004

Accompanying the brilliance-upgrading project at the Photon Factory storage ring, the beam-position monitor (BPM) system has been renovated. The new system was designed to enable precise and fast measurements to correct the closed-orbit distortion (COD), as well as to feed back the orbit position during user runs. There are 42 BPMs newly installed, amounting to a total of 65 BPMs. All of the BPMs are calibrated on the test bench using a coaxially strung metallic wire. The measured electrical offsets are typically 200 µm in both directions, which is 1/2–1/3 of those of the old-type BPMs. In the signal-processing system, PIN diode switches are employed in order to improve reliability. In the fastest mode, this system is capable of measuring COD within about 10 ms; this fast acquisition will allow fast suppression of the beam movement for frequencies up to 50 Hz using a global feedback system.
A compact superconducting ring as a radiation source for X-ray crystallography
Authors: Iwasaki H. , Kurosawa N. , Masui S. , Fujita S. , Yurugi T. , Yoshimura Y. , Nakamura N.
Published: July 2004

A compact superconducting storage ring installed at Ritsumeikan University is operated at an electron-beam energy of 0.575 GeV and an initial beam current of 300 mA. The radius of the circular electron orbit is as small as 0.5 m, suggesting that the radiation emitted contains short-wavelength components. With an imaging plate as a detector, X-ray precession diffraction patterns were recorded for organic single crystals within a reasonable period of time using radiation of wavelength 0.155 nm (8 keV) to 0.248 nm (5 keV). The use of the radiation in the structural study of organic crystals containing 3d metal atoms using the phenomena of anomalous scattering is described. If appropriately planned, X-ray diffraction and/or scattering experiments can be made at the compact ring without recourse to a large-scale ring.