A beamline has been constructed at Stanford Synchrotron Radiation Laboratory (SSRL) whose radiation source is a multipole permanent magnet '\.\iggler 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 ofvacuum, safety, and optical components capable oftransporting photons to one hard xray (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 operation of Metro, red (AC buses), green (Non-AC buses), purple (HoHo buses) and orange buses ( Cluster buses) has provided a new and strong image to public transport in Delhi. Due to availability of a large number of public modes, the concept of multi modal transport has led to success in Delhi and other Indian metropolitan cities. Integration and Interchange are two important components of multi modal transport system and hence security perceptions of the commuters' at interchange need to be assessed for implementation of both general and specific security measures. In this context, qualitative model based on perceived relative importance of five security attributes of commuters' at metro bus interchange has been developed. It is suggested that public transport sector has to make efforts and design the system to prepare and protect passengers and infrastructure. The other non-transport factors such as built environment, design, staff skills, awareness, regular inspection, uninterrupted power supply, etc can contribute to make public transport systems more secure. It is important to have policy level co-ordination among various operators and facilitators to follow up actions in emergency situations. Further, a separate "Multi Modal Transport Security Regulatory Authority" with strong fiscal base to support the cost of security measures and consequences of security failures, must be created.
New platinum-coated grazing incidence mirrors with low surface roughnesses have been developed to focus bending magnet radiation from the SSRL/SLAC SPEAR storage ring on the entrance slits of two Beam Line VIII grating monochromators. The first mirror 1n the toroidal grating monochromator (TGM) branch Is a cooled SIC cylinder capable of absorbing synchrotron radiation power levels of up to 260 watts without excessive distortion. Tht-; mirror deflects the beam vertically through a 12' angle and focuses it sagitally on the TGH entrance slit plane. The second TGM optica! element 1s a fused-silica spherical mirror with a large radius of curvature that deflects the beam vertically through an additional 12° and focuses ft tangentlally with 3/1 demagntf icat Ion. The first mirror In our spherical grating branch 1s a 5°-vert1cally deflecting, cooled SIC torold designed to focus tangentlally on the monochromator entrance slits and sagitally on the exit slits. A 4°-deflectlng fused silica mirror is used after the exit slits In each beam 11ne to refocus on to the sample. For this application a thin cylinder is bent to approximate an ellipsoid. The mirrors are now installed at SSRL and performance measurements are planned. Quali tatively the focus of the TGM optics at the entrance slit plane appears very good. In this paper we discuss considerations leading to the choice of SiC for each of the two first mirrors. Ue present highlights of the development of these mirrors with some emphasis on S1C polishing techniques. In addition, the specialized metrology developed to produce the more difficult figure of the torold will be described. Measured surface roughness and figure results will be presented.
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