Synchrotron radiation background

M. Sullivan Calculation of the TPC Vertex Chamber Synchrotron Radiation Backgrounds Jul31,1991... 

If the synchrotron is operated in discontinuous mode, the storage ring will be refilled two or three times every day. The interval between two consecutive refills is called a synchrotron radiation run. The parasitic scattering (machine background) should at least be recorded once within each synchrotron radiation run. You might consider... 

In this chapter, we briefly discuss the theoretical background of polarized x-ray absorption spectroscopy (PXAS). Many of the recent applications of synchrotron radiation to polarized absorption edge structure and to EXAFS are discussed, with particular emphasis being given to the study of discrete molecular systems. We present here some indication of the potential applications of PXAS to systems of chemical and biological interest. 

The statistical precision of better than 10 can be achieved by 10 scattered photons in a given interval of scattering angle. Lets divide the scattering curve into 10 intervalls, then 10 ° scattered photons would be sufficient to solve the above problem. Assuming that the detector would count 10 useful photons per second and about the same amount of background scattering, then the 86 400 seconds of a 24 hour day at a 100% efficient synchrotron radiation source would just allow to do this experiment. Realistically one has to foresee at least two days of beam time for such an experiment. 

The SAXS instrument was constructed at ANL and used on the Basic Energy Sciences Synchrotron Radiation Center (BESSRC-CAT) undulator beamline ID-12 at the APS. Monochromatic X-rays (8.98 keV here) were scattered off the samples and collected on a 15 cm X 15 cm Mosaic CX. D array (1538 x 1538 pixels). This system is capable of a resolution of -0.5 s. The scattered intensities were corrected for absorption, empty cell scattering, and instrument background. 

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