Advanced photon source

Soft X-ray absorption measurements are done at low-energy synchrotron X-ray facilities such as the UV ring at NSLS or the Advanced Photon Source (APS) at Lawrence Berkeley National Laboratory (LBNL). The beam size is typically 1 mm in diameter. The electron yield data are usually obtained in the total electron yield (EY) mode, measuring the current from a channel electron multiplier (Channeltron). Sometimes a voltage bias is applied to increase surface sensitivity. This is referred to as the partial electron yield (PEY) mode. Huorescence yield (EY) data are recorded using a windowless energy dispersive Si (Li) detector. The experiments are conducted in vacuum at a pressure of 2 X 10 torr. 

It should be mentioned that another synchrotron source, the Advanced Photon Source (APS) will be built at the Argonne National Laboratory and should be operational in the mid-1990s.]... 

In situ CO-TPR XAFS studies were performed at the Materials Research Collaborative Access Team (MR-CAT) beam line at the Advanced Photon Source,... 

Bulk and micro-XAFS analyses were performed at the PNC-CAT s bending magnet (20-BM) and undulator (20-ID) beamlines of the Advanced Photon Source (APS), Argonne, IL, USA. Other microanalytical and mineralogical characterization studies were conducted at CANMET. Details of the methodology can be found in Paktunc (2008) and other publications by the author. 

The XAFS experiments were carried out at the Pacific Northwest Consortium -Collaborative Access Team s (PNC/XOR) beamline at the Advanced Photon Source... 

Advanced Photon Source (APS), 26 412 Advanced Photo System (APS), 19 266 Advanced power reactors, 17 594—595 Advanced SclairTech dual-reactor system, 20 197... 

Acknowledgements We thank Robert Gordon and Steve Heald of the Advanced Photon Source, Chicago and David Gray, Nathan Reid, David Lentz and Gwendy Hall for commenting on earlier versions of the abstract. 

SXRF imaging and XANES analysis were made at the PNC/XOR beamline at the Advanced Photon Source, Argonne National Laboratory (Heald. et al 2007) using photon energies of 17.0 and 12.5 keV for SXRF imaging and 11.8 to 12.1 keV for XANES analysis. XANES analysis across the Au L3 edge used steps of 5 eV (from 11.82 - 11.89 keV), 0.5 eV (from 11.89-11.97 keV) and 0.07 k (from 11.97-12.1 keV) with a one second dwell per step. 

Rapid collection of diffraction data depends on access to such powerful X-ray sources. This chapter describes how high-quality, high-throughput data collection can be achieved. We use SGX-CAT, the SGX Collaborative Access Team beamline, located at the Advanced Photon Source of Argonne National Laboratory as an example to illustrate the concepts behind the design of, and the hardware used at, synchrotron beamlines. Many of these features are found, individually or in combination, at other beamlines. Data collection at synchrotron sources produces enormous quantities of data. We, therefore, also discuss the information technology infrastructure and software that is necessary for effective data management. 

SGX-CAT maintains a direct T1 network connection from the Advanced Photon Source in Illinois to SGX San Diego. Database inquiries are handled over this link. Interactions with the database occur in three ways. An extensive web-based system is used for data entry and retrieval. For crystals generated by external users of the beamline, upload of an electronic spreadsheet transfers the required crystal data attributes to the SGX LIMS. For automated operations, such as crystal screening and data collection, custom scripts place the computed results directly into the database. 

APS Advanced Photon Source at Argonne National Laboratories (www.aps.anl.gov)... 

For example, at present such work can be done at the Advanced Photon Source at the Argonne National Laboratory in the United States, among other places. 

Sandy, A. R., Lurio, L. B., Mochrie, S. G. J., Malik, A., Stephenson, G. B., Pelletier, J. F., and Sutton, M. (1999). Design and characterization of an undulator beamline optimized for small-angle coherent X-ray scattering at the advanced photon source. J. Synchrotron Radiat. 6, 1174-1184. 

Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL... 

Acknowledgments I would like to thank Mohammed Abu Haija, Phil Ryan, and Sean Frigo for various contributions to this work. This work was performed at the Advanced Photon Source and was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-06CH11357. 

Wasielewski then focused on a particular ring structure found in antenna proteins to see how a system could be developed based on chlorophyll that mimics some of these features. It turns out that the spectral shift does not explain anything. He said that there needs to be a structural tool to present specific information. The Advanced Photon Source, the brightest X-ray source in the country, at Argonne National Laboratory, is currently being used for this purpose. 

Figure 2 Experimental arrangement for measurements of the Fe nuclear resonance at the Advanced Photon Source (APS). In the standard fill pattern, electron bunches with a duration of 100 ps are separated by 153 ns. X-ray pulses are generated when alternating magnetic fields in the undulator accelerate these electron bunches. The spectral bandwidth of the X-rays is reduced to 1 eV by the heat-load monochromator and to 1 meV by the high-resolution monochromator. At the sample, the flux of the beam is about 10 photons/s. APD indicates the avalanche photodiode used to detect emitted X-rays. The lower right inset illustrates that counting is enabled only for times weU-separated from the X-ray pulse, so that only delayed photon emission resulting from decay of the nuclear excited state contributes to the experimental signal...

The authors acknowledge EPSRC support under grant number GR/N03006. Use of the Advanced Photon Source was supported by the U.S. Depaitmenl of Energy. Basic Energy Sciences, Office of Energy Research, under Contract No. W-31-109-ENG-38. 

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