scholarly journals The PM3 beamline at BESSY II

Author(s):  
Torsten Kachel

<p>PM3 merges the developments of the former BESSY I SX700 III monochromator for elliptically polarized VUV radiation and of BESSY II collimated plane grating monochromators. This way it is possible to achieve circular polarization from a BESSY II dipole in the range 20 – 2000 eV with high photon flux, high energy resolution and high stability.</p>

1993 ◽  
Vol 37 ◽  
pp. 405-411
Author(s):  
C. S. Rossington ◽  
N. W. Madden ◽  
K. Chapman

AbstractA new x-ray spectrometer has been constructed which incorporates a novel large area, low capacitance Si(Li) detector and a low noise JFET (junction field effect transistor) preamplifier. The spectrometer operates at high count Tates without the conventional compromise in energy resolution. For example, at an amplifier peaking time of 1 p.sec and a throughput count rate of 145,000 counts sec-1, the energy resolution at 5.9 keV is 220 eV FWHM. Commercially available spectrometers utilizing conventional geometry Si(Li) detectors with areas equivalent to the new detector have resolutions on the order of 540 eV under the same conditions. Conventional x-ray spectrometers offering high energy resolution must employ detectors with areas one-tenth the size of the new LBL detector (20 mm2 compared with 200 mm2). However, even with the use of the smaller area detectors, the energy resolution of a commercial system is typically limited to approximately 300 eV (again, at 1 μsec and 5.9 keV) due to the noise of the commercially available JFET's. The new large area detector is useful in high count rate applications, but is also useful in the detection of weak photon signals, in which it is desirable to subtend as large an angle of the available photon flux as possible, while still maintaining excellent energy resolution. X-ray fluorescence data from die new spectrometer is shown in comparison to a commercially available system in the analysis of a dilute muhi-element material, and also in conjunction with high count rate synchrotron EXAFS applications.


2018 ◽  
Vol 51 (3) ◽  
pp. 761-767 ◽  
Author(s):  
Tom Faske ◽  
Wolfgang Donner

This article reports the development and characterization of a laboratory-based high-resolution X-ray powder diffractometer equipped with a 5.5 T magnet and closed-cycle helium cryostat that is primarily designed for the investigation of magneto-structural phase transitions. Unique features of the diffractometer include the position-sensitive detector, allowing the collection of an entire diffraction pattern at once, and the high energy resolution with Mo Kα 1 radiation. The ability to utilize a lower energy resolution but higher photon flux by switching to an X-ray mirror monochromator makes it a versatile setup for a variety of compounds. In this contribution, details of the design and performance of the instrument are presented along with its specifications.


1995 ◽  
Vol 66 (2) ◽  
pp. 2072-2074 ◽  
Author(s):  
M. Bissen ◽  
M. Fisher ◽  
G. Rogers ◽  
D. Eisert ◽  
K. Kleman ◽  
...  

2017 ◽  
Vol 139 (49) ◽  
pp. 18024-18033 ◽  
Author(s):  
Rebeca G. Castillo ◽  
Rahul Banerjee ◽  
Caleb J. Allpress ◽  
Gregory T. Rohde ◽  
Eckhard Bill ◽  
...  

2007 ◽  
Vol 127 (16) ◽  
pp. 164702 ◽  
Author(s):  
Alessandro Baraldi ◽  
Erik Vesselli ◽  
Laura Bianchettin ◽  
Giovanni Comelli ◽  
Silvano Lizzit ◽  
...  

2015 ◽  
Vol 112 (52) ◽  
pp. 15803-15808 ◽  
Author(s):  
Ofer Hirsch ◽  
Kristina O. Kvashnina ◽  
Li Luo ◽  
Martin J. Süess ◽  
Pieter Glatzel ◽  
...  

The lanthanum-based materials, due to their layered structure and f-electron configuration, are relevant for electrochemical application. Particularly, La2O2CO3 shows a prominent chemoresistive response to CO2. However, surprisingly less is known about its atomic and electronic structure and electrochemically significant sites and therefore, its structure–functions relationships have yet to be established. Here we determine the position of the different constituents within the unit cell of monoclinic La2O2CO3 and use this information to interpret in situ high-energy resolution fluorescence-detected (HERFD) X-ray absorption near-edge structure (XANES) and valence-to-core X-ray emission spectroscopy (vtc XES). Compared with La(OH)3 or previously known hexagonal La2O2CO3 structures, La in the monoclinic unit cell has a much lower number of neighboring oxygen atoms, which is manifested in the whiteline broadening in XANES spectra. Such a superior sensitivity to subtle changes is given by HERFD method, which is essential for in situ studying of the interaction with CO2. Here, we study La2O2CO3-based sensors in real operando conditions at 250 °C in the presence of oxygen and water vapors. We identify that the distribution of unoccupied La d-states and occupied O p- and La d-states changes during CO2 chemoresistive sensing of La2O2CO3. The correlation between these spectroscopic findings with electrical resistance measurements leads to a more comprehensive understanding of the selective adsorption at La site and may enable the design of new materials for CO2 electrochemical applications.


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