ABSTRACT
A 100 MeV eight-turn accelerator-recuperator intended to drive a high-power infrared free-electron laser (FEL) is currently under construction in Novosibirsk. The first stage of the machine includes a one-turn accelerator-recuperator that contains a full-scale RF system. It was commissioned successfully in June 2002.
ABSTRACT
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.
ABSTRACT
A low-energy positron beam is a unique probe of materials. In high-energy electron and positron storage rings it is possible to generate intense synchrotron radiation with a photon energy of 1-3 MeV by installing a high-field (8-10 T) superconducting wiggler. High-energy photons are converted to low-energy positrons by using a suitable target-moderator system. For an 8 GeV electron storage ring at a beam current of 100 mA, final yields are estimated to be about 10(8)-10(10) slow-e(+) s(-1) or larger depending on the moderation efficiency, with the size of the positron source 10(1)-10(2) cm(2). In the present work a wiggler magnetic system of 10 T is proposed. The main parameters of the superconducting wiggler are presented.
ABSTRACT
A superconducting 7 T wiggler is under fabrication in a collaboration between Budker INP and LSU CAMD. The wiggler magnet has been successfully tested inside a bath cryostat and a maximum field of 7.2 T was achieved after six quenches. The main parameters of the wiggler and the method of the wiggler installation onto the storage ring are discussed.
ABSTRACT
The K-edge dichromography method was applied for preliminary bronchography test studies at the angiography station on the VEPP-3 storage ring. Images of xenon distribution over the test sample of Plexiglass were acquired. The obtained results demonstrate that thicknesses of xenon as small as 0.5 mm can be visualized.
ABSTRACT
A low-energy positron beam is a unique probe of Fermi surfaces, defects, surfaces and interfaces. In high-energy electron and positron storage rings (E > 6 GeV) it is possible to generate intense synchrotron radiation with 1-3 MeV photons by installing a high-field superconducting wiggler. The strength of the wiggler should be ~8-12 T. High-energy photons are emitted from the wiggler and converted to low-energy positrons by using a suitable target-moderator system. For an 8 GeV electron storage ring at a beam current of 100 mA, final yields are estimated to be ~10(10)-10(12) (slow-e(+) s(-1)) with the size of positron source ~10(2)-10(3) cm(2). The possibility of increasing the brightness of the low-energy positron beam is discussed. Advantages of using synchrotron radiation for producing positrons are pointed out. The effect of a superconducting wiggler on the stored electron beam is also discussed.
ABSTRACT
BACKGROUND: Tracer studies are an important tool to obtain information about the processes involved in the immunological response. Colloidal gold is widely used as a tracer, but its small size of label can cause some difficulty during low-resolution analysis. To overcome this difficulty, we developed a new method to follow the route of tracer movement within lymph nodes. METHODS: We applied conventional X-ray analysis, X-ray fluorescence analysis (XFA) subtractional microscopy using synchrotron radiation (SR) beams, light microscopy, and ultrastructural analysis to study the distribution and quantity of colloidal gold coupled with albumin within rat parasternal lymph node 2, 4, 6, 8, and 10 h after intrapleural injection of the tracer. RESULTS: At all the time points XFA-SR revealed that tracer formed a circle with a maximum concentration in the node periphery. XFA-SR measured colloidal gold concentration in the nodes reached its maximum (0.5-0.75 weight %) in 6-8 h. Subtractional microscopy revealed superficially located groups of cells filled with colloidal gold tracer. Light microscopy and ultrastructural analysis confirmed that the tracer was concentrated in the reticular cells, situated in the sinuses of the node. Sinusoidal reticular cells concentrated tracer at much higher rates than sinusoidal macrophages. Four hours after injection, gold appeared in the lysosomes of the follicular reticular cells. At the same time point, evidence of antigen presentation was obtained. Antigen presentation proved to be an extremely rara event since only one ultrastructural incident was found in 150 analysed grids. CONCLUSIONS: SR is a valuable tool for the analysis of gold tracer passage within the living organism.