GeV Electron Storage Ring Research Articles

LNLS status report

The Brazilian synchrotron light source consists of a 1.15 GeV electron storage ring with a 100 MeV injector. Most of their components have already been developed in-house and production has started. The increase of injection energy is being considered via a booster, for full energy, or by recirculating the beam in the LINAC (200 MeV) [R. H. Farias et al. (unpublished)]. An update of the production and characterization of the accelerators components and beamlines is presented.

Thermal effects of undulator radiation on Si optics for a plane grating monochromator

Insertion devices on the third-generation 1.5 GeV electron storage ring MAX II will subject the grazing incidence mirrors and gratings of new soft x-ray beamlines to high thermal loads. These thermal loads will cause distortion in the optical surfaces which can be reduced to acceptable levels by the proper choice of substrate material and cooling. A finite element analysis of the temperature variation and thermal distortions is carried out for Si plane mirrors and gratings under thermal load from the 66 mm period undulator planned for MAX II. The energy dependence of the reflectivity for Au-coated mirrors is taken into account. The minimum cooling requirements are determined for each of these optical components in the beamline. The effect of the final induced figure errors on the performance of a plane grating monochromator are discussed.

Response of thermoluminescent lithium fluoride (TLD-100) to photon beams of 275, 400, 500, 600, 730, 900, 1200, 1500, and 2550 eV

LiF:Mg,Ti (TLD-100) extruded ribbons and cleaved crystals were exposed to monoenergetic photons of 275-2550 eV energy to determine their potential usefulness as radiation dosimeters for radiobiology experiments at these energies. The radiation source was synchrotron radiation from the 1 GeV electron storage ring, Aladdin. The authors report TLD response and glow curves for He- and air-annealed dosimeters. The undesirable effects of air annealing increase with decreasing photon penetration in the dosimeter. Under certain experimental conditions, UV radiation produced anomalous bleaching of high-temperature traps. The crystals and the chips presented a supralinear response, Supralinearity factors were determined to be of the order of 1.5 for crystals, and 1.7 for the chips. The authors' results indicate that TLDs are a reliable means to monitor the total energy deposited in irradiated cells and are now used routinely for radiobiology cell irradiations.

Design and performance of two CsI/NaI(T1) calorimeters in an internal target detector setup

The design, construction and performance of two total-absorption calorimeters for nuclear physics experiments is described. They are used in conjunction with an internal polarized deuterium target in the 2 GeV electron storage ring VEPP-3 in Novosibirsk to detect scattered electrons with energies up to 1.9 GeV and protons up to 600 MeV. Each calorimeter consists of three layers of CsI(T1) blocks followed by two layers of NaI(T1) blocks, a total of 16 radiation lengths of scintillating material. Scintillation light from the CsI(T1) is collected by wavelength-shifter plates and sensed by silicon photodiodes connected to charge-sensitive preamplifiers. The NaI(T1) is read out with photomultiplier tubes. An overview is given of the performance of these calorimeters together with the other components of the detector system under the background conditions of the internal target setup. The electron energy resolution obtained was ≈10% (FWHM).

Construction and commissioning of the Synchrotron Radiation Research Center vacuum system

The installation of the vacuum system of the Synchrotron Radiation Research Center 1.3 GeV electron storage ring was completed in January 1993. Both the straight (S-) chambers and bending (B-) chambers are made of aluminum alloy. Oil-less machining processes were adopted in the fabrication of the B-chambers and some components of the S-chambers. Stringent welding processes were performed in a clean room in order to get a good welding quality and a clean chamber surface. The pumping system is a combination of several kinds of oil-free pumps. In the commissioning phase, the photon induced desorption phenomenon was clearly observed. The major desorbed gases are H2, CH4, CO, and CO2. The desorption yields of these gases are described in this paper. An interlock system for the purpose of vacuum safety is also built in the system in order to increase the reliability of the vacuum operation. In the early stage of the commissioning, the malfunction of some ion gauges and quadrupole mass spectrometers were observed due to the beam interference. A solution has been found to reduce the interference.

Vacuum System of the Third-Generation Synchrotron Light Source at SRRC.

The SRRC 1.3 GeV electron storage ring was designed as a third-generation synchrotron light source. Aluminum alloys were adopted as the materials of the ring vacuum chambers. The anti-chamber structure with a “concentrated + distributed ion pump” pumping configuration effectively removed the desorbed gas molecules in the bending chamber. A computer program was devised to simulate the distribution of the outgassing rate in the storage ring. It was shown that the arrangement of the pumps, according to the simulation, was effective to reduce the average pressure. An oil-free machining method with complete oil-free pumping configuration resulted in the reduction of the hydrocarbon contamination on the surface of the chamber. The welding and installation work were performed in a clean room or dust-controlled area so that little dust trapping was observed during the machine operation. The desorbed gases were mainly hydrogen molecules, which had less effect on the beam lifetime. An accumulated beam dose of>80 A·h was quickly achieved and the pressure rise per electron beam current (dP/dI) was reduced by three orders of magnitude in a short time period of normal operation.

The straight vacuum chambers of the SRRC 1.3 GeV electron storage ring

The straight vacuum chambers (S-chamber) of the SRRC 1.3 GeV electron storage ring are designed, fabricated and tested. Vacuum pipes, bellows, flanges, pumping ports and most of the other components are made of aluminum. The S-chambers are designed to have the function of reducing radio-frequency ( rf) impedance and removing the heat created by synchrotron radiation. A stringent tungsten-inert gas (TIG) welding process is performed to minimize the deformations in both longitudinal and transverse directions. In order to achieve uhv, in situ bakeout by tape heaters is adopted. The testing results showed that the designs for removing the baking-related problems work well.

Scientific program of the advanced light source at LBL

Abstract Construction of the Advanced Light Source (ALS) at the Lawrence Berkeley Laboratory is nearing completion, with operation as a US Department of Energy national user facility scheduled to begin in the spring of 1993. Based on a low-emittance, 1.5 GeV electron storage ring with ten long straight sections available for insertion devices and, initially, 24 bend-magnet ports, the ALS will be a third-generation source of soft X-ray and ultraviolet (collectively, the XUV) synchrotron radiation. Experimental facilities (insertion devices, beamlines, and end stations) will be developed and operated by participating research teams working with the ALS staff. The ability to exploit the high spectral brightness of the ALS was the main criterion for PRT selection. In the XUV spectral regions served by the ALS, a major benefit of high brightness will be the ability to achieve spatial resolution in the neighborhood of 200 A in X-ray microscopy and holography and in spatially resolved spectroscopy. Other beneficiaries of high brightness include very-high-resolution spectroscopy, spectroscopy of dilute species, diffraction from very small samples, and time-resolved spectroscopy and diffraction.

The SIBERIA dedicated synchrotron radiation source: status report on the storage rings complex at the Kurchatov Institute for Atomic Energy

This paper reviews the status of the SIBERIA storage rings complex. The parameters of the linac, booster synchrotron and main ring are given. The transfer of the SIBERIA-1 storage ring to its new site is described. The main parameters of the engineering systems for the SIBERIA complex are presented. The assembly of the SIBERIA-2 storage ring is planned to be finished in 1991. The SIBERIA storage rings complex has been constructed at the Kurchatov Institute for Atomic Energy (IAE) and is the first dedicated synchrotron radiation source in the USSR. The facility includes the SIBERIA-1 450 MeV electron storage ring, the SIBERIA-2 2.5 GeV electron storage ring, two electron transport lines EOC-1 and EOC-2, and an 80–100 MeV electron linac which serves as the injector. The general layout of SIBERIA is shown in fig. 1. All accelerators of the SIBERIA facility are designed and manufactured at the Institute of Nuclear Physics (INP) at Novosibirsk.

Utilization of a commercially supplied synchrotron radiation source

Louisiana State University (LSU) is developing the Center for Advanced Microstructures and Devices [1] (CAMD) in Baton Rouge, Louisiana. The centerpiece of CAMD will be a 1.2 GeV electron storage ring [2] purchased from Maxwell Laboratories, Inc. The high-tech building for CAMD has been designed by TECH-IV [3] of Baton Rouge with engineering support from Lester B. Knight and Associates [4] of Chicago. The storage ring has been optimized for X-ray lithography. The procedures developed at CAMD for printing integrated circuits may well be of significant importance to US competitiveness in semiconductor and related industries. However, the spectral range of the ring also supports scientific and engineering activities in several other areas.

The advanced light source at the Lawrence Berkeley laboratory

The Advanced Light Source (ALS), a national facility currently under construction at the Lawrence Berkeley Laboratory (LBL), is a third-generation synchrotron light source designed to produce extremely bright beams of synchrotron radiation, in the energy range from a few eV to 10 keV. The design is based on a 1–1.9 GeV electron storage ring (optimized at 1.5 GeV), and utilizes special magnets, known as undulators and wigglers (collectively referred to as insertion devices), to generate the radiation. In this paper we describe the main accelerator components of the ALS, the variety of insertion devices, the radiation spectra expected from these devices, and the complement of experiments that have been approved for initial operation, starting in April 1993.

Technological applications of synchrotron radiation at the synchrotron sadiation center of the university of Wisconsin

The use of synchrotron radiation for fundamental research in a wide range of disciplines is now well established, world wide. Not so well known are the technologically oriented programs that are now in progress on Aladdin [E.M. Rowe, Nucl. Instr. and Meth. B24/25 (1987) 414], the 1 GeV electron storage ring at the Synchrotron Radiation Center of the University of Wisconsin-Madison. We describe three such programs: X-ray lithography, high T c superconductor to normal conductor junction technology, and X-ray microscopy.

DELTA, a new storage-ring-FEL facility at the University of Dortmund

This paper presents the concept of the new FEL facility at the 1.5 GeV electron storage ring DELTA, currently under construction at the University of Dortmund. Furthermore, detailed information about the accelerator itself and the first FEL experiment (FELICITA I) are given.

Beamline 10: A multipole wiggler beamline at SSRL (invited)

A beamline has been constructed at Stanford Synchrotron Radiation Laboratory (SSRL) whose radiation source is a multipole permanent magnet wiggler installed in a straight section of the SPEAR 3–3.5 GeV electron storage ring. The wiggler is a hybrid design that utilizes Nd–Fe alloy magnet material combined with Vanadium Permendur poles. It is approximately 2 m long and has 15 full wiggler periods. Its field is regulated by varying its gap height. It has a peak operating field, limited by the electron beam vacuum chamber vertical aperture, of 1.4 T. The beamline consists of vacuum, safety, and optical components capable of transporting photons to one hard x-ray (3–30 keV) end station, with provisions for implementing up to two additional branch lines. The existing hard x-ray branch can be focused by a Pt-coated toroidal mirror with a cutoff energy of approximately 22 keV. The experimental end station is serviced by a Hower–Brown type double crystal monochromator. The wiggler and beamline construction was completed in the fall of 1987 and was operated for a brief period for characterization and experimental use. We present design details and results of the initial characterization studies.

The control system of the photon factory storage ring

The Photon Factory 2.5 GeV electron storage ring at KEK, a dedicated machine for synchrotron radiation, stored its first beam on March, 1982. The first control system of the storage ring comprised seven distributed minicomputers connected through a star-type network. However, from 1985 they have been gradually replaced in order to meet increasing system requirements. At present, the control system uses four “supermini” computers as device controllers and a general-purpose computer as a library computer. These computers are connected to each other through a token ring-type network. Each control computer independently performs several processes. However, console functions as man-machine interfaces of all processes can be treated in a unified way using the network. A prototype database for operation logging has been completed and tested.

Maximum: A scanning photoelectron microscope at Aladdin

The recent successful installation of the 30-period undulator on Aladdin, the 1 GeV electron storage ring at the Synchrotron Radiation Center of the University of Wisconsin, opens new possibilities for photoelectron spectroscopy. In particular, the high brightness of the machine, together with innovative optics, make possible the application of photoelectron spectroscopy to high-resolution soft X-ray microscopy. We call this system MAXIMUM (for Multiple Application X-ray IMaging Undulator Microscope). The proposed optical system will have a lateral resolution of better than 1000 Å and a resolving power of better than 200 at 100 eV. After monochromatization, the radiation will be focused on a pinhole that can range in diameter from 1 to 100 μm, and will be prepared by lithographic techniques on a thin nickel film. The image of the pinhole, suitably demagnified, will be relayed to the sample. The image resolution and magnification can be adjusted by changing the pinhole size and the scanning step. A Schwartzschild objective can produce a demagnified image of the pinhole which is diffraction limited even at a wavelength of 40 Å. At 100 Å and at a numerical aperture of 0.2, the objective can produce a 250 Å diameter spot. High flux will be achieved with a Mo-Si multilayer coating, for which preliminary experiments have demonstrated reflectivities near 40% at normal incidence. Other focusing elements (Fresnel zone plates and Kirkpatrick-Baez objectives) will also be implemented.

Nuclear excitation in 189 Os with synchrotron radiation

The 6 h radioactivity of 189mOs was observed after irradiation of 189Os with white synchrotron radiation produced at a superconducting wiggler installed in a 2.5 GeV electron storage ring. It was considered that production of the activity resulted mainly from the excitation of the 70 keV nuclear level in 189Os through a process referred to as nuclear excitation by electron transition (NEET). The NEET probability was deduced to be (5.7 ± 1.7) × 10 −9 per created K-hole, which was smaller by a factor of thirty than the previous result obtained with electron bombardment.

Photon factory: status in 1986

The Photon Factory (PF) consists of a 2.5 GeV electron storage ring, a full energy injector linac and experimental facilities, and has been operated steadily in the third fiscal year 1985 since it was opened as a national synchroton light source in June 1983. The linac has served as the injector of the Photon Factory Ring and the 6 GeV Accumulation Ring of TRISTAN. The light source, 2.5 GeV-electron storage-ring has been running steadily after overcoming various types of instabilities and a lifetime more than 8 hr was achieved for a storage current of 200 mA and 300 mA with and without the vertical wiggler, respectively. The user's experiments started with 8 beam lines (25 experimental stations) in 1983. In addition to commissioning two beam lines in 1985, now, two new beam lines are under construction and two are under design. In collaboration with outer organizations, five beam lines are in operation or under construction.

Response functions of a Si(Li) detector for 1.3–4.0 keV monochromatic photons

The response functions of a Si(Li) detector have been measured for monochromatic photons in the energy range 1.3–4.0 keV using synchrotron radiation from a 2.5 GeV electron storage ring. The contribution of the low-energy tail, just below the Gaussian full-energy peak, changed drastically at the boundary energy of the Si-K. absorption edge. The structure of the low-energy tail and the tail-to-peak ratio can be described by introducing a new simple geometrical model. The results of a fit based on the model were excellent for all data obtained over a wide energy range.

SOR-RING at ISSP and its activity

The present status of SOR-RING, a 0.38 GeV electron storage ring dedicated to synchrotron radiation science and the materials research at the Institute for Solid State Physics of the University of Tokyo, and a brief introduction of its recent activity in the VUV science are described. The correlation between the intensity of available light and the amount of the stored beam current has been observed. The result indicates the effect of the change in the electron beam size. Experience with single-bunch-mode operation and efforts to improve beam stability as well as a few examples of the experimental data in the solid state research are also described.