X-ray Scattering at Sulfur and Phosphorus Edges
2014 Advanced Light Source User Meeting
http://www-als.lbl.gov/index.php/user-information/users-meeting.html
October 6-8, 2014
Lawrence Berkeley National laboratory
Berkeley CA 94720
Workshop Organizers
Alex Hexemer (ALS, LBNL), Cheng Wang (ALS, LBNL), Petrus Zwart (PBD, LBNL), Chenhui Zhu (ALS, LBNL)
ahexemer@lbl.gov, cwang2@lbl.gov, phzwart@lbl.gov, chenhuzhu@lbl.gov
Summary
The goal of this one-day workshop is to bring together researchers who currently utilize soft x-ray (e.g. at carbon K-edge) or tender x-ray (e.g. at sulfur or phosphorus k-edge) scattering with scientists who could benefit from using the technique. The current and potential research topics and analysis techniques will be discussed, aiming to expand resonant x-ray scattering to a much broader range, including the sulfur-containing energy materials and phosphorus-containing biological materials (DNA, proteins, etc).
Invited speakers
Dr. Wei Chen, Materials Science Division, Argonne National Lab, Chicago
Prof. Hiroshi Okuda, Kyoto University, Japan
Dr. Ron Pindak, NSLS II, Brookhaven National Lab, New York
Dr. Giuseppe Portale, European Synchrotron Radiation Facility, Grenoble, France
Dr. Tod Pascal, Molecular Foundry, Lawrence Berkeley National Lab, Berkeley, CA
Dr. Armin Wagner, Diamond Light Source, UK
Dr. Jan Wernecke, Physikalisch-Technische Bundesanstalt, Germany
Preliminary workshop schedule:
(To attend the workshop you need register for the 2014 ALS user meeting (link below), which will be held at Berkeley Lab October 6-8. Workshop will begin October 7th early afternoon and end on October 8th noon. When you register, you must indicate “scattering at sulfur and phosphorus edges” as your workshop.)
http://www-als.lbl.gov/index.php/user-information/users-meeting/556-registration.html
Tuesday, October 7, 2014
Location: building 2, 400F
(from ALS patio/tent, walk across the 'bridge' to building 2, 400F is on the same floor )
Wednesday, October 8, 2014
Location: building 2, 400F
Title/abstract:
Dr. Wei Chen, Materials Science Division, Argonne National Lab, Chicago
Prof. Hiroshi Okuda, Mater. Sci. Eng., Kyoto University,Japan
Topic: GISAXS measurements near the absorption edge of P
Abstract: GISAXS measurements around the photon energy of 2 keV made at Photon Factory, KEK Japan are to be presented. GISAXS measurements in tender X-ray region are useful for depth-resolved measurements and anomalous GISAXS. The measurements were made with image plates and under vacuum. Large refractive indices at the tender X-ray region are convenient for depth resolved GISAS for two reasons; one is strong absorption, and the other is large critical angle, which is useful to reduce the effect of irregularity of the samples such as surface undulation. Some results on GISAXS measurements of soft materials thin films are presented. Present state of the measurements for phospholipid alloy systems and some problems are discussed
Dr. Ron Pindak, NSLS II, Brookhaven National Lab, New York
Topic: Liquid Crystals - Resonant X-ray Scattering at the Sulfur, Chlorine, & Selenium Edges
Abstract: Resonant x-ray scattering provides a direct probe of orientational structures in liquid crystals with periodicities that range from molecular dimensions (0.1 nm) to dimensions that can be observed with visible light (a few microns). We have applied this technique to study interlayer orientational ordering in ferro-, ferri-, and antiferro-electric tilted liquid crystal smectic phases in well-aligned free-standing films as well as in a device cell geometry, that is, sandwiched between two thin (0.15 mm) glass plates with an ITO conductive layer and a rubbed polymer alignment coating. The liquid crystal compounds studied as free-standing films typically contained either a sulfur (K-edge = 2.47 keV) or chlorine (K-edge = 2.82 keV) atom either in the molecule itself or in an additive. For the device cells, in order to have the x-rays penetrate the glass plates, we used liquid crystal compounds containing a selenium atom that has a higher energy x-ray resonant energy (K-edge = 12.7 keV). We studied both linear and bent-core molecules. The bent-core molecules, even when non-chiral, can develop chiral structures that are ferro- or antiferro-electric. They also exhibit a number of modulated phases. I’ll provide an overview of this work highlighting the most important discoveries and open issues for the future.
Dr. Giuseppe Portale, European Synchrotron Radiation Facility, Grenoble, France
Topic: Soft and intermediate X-ray energies opportunities in polymer science and nanoscience.
Abstract: Hard X-rays (E = 8-100 KeV) are by far the most commonly used in order to investigate structure in soft condensed matter and nanostructured materials. However, the use of lower X-ray energies can give access to study selectively structures involving light elements such as C, F, O and S.
Recently, it has been shown that the use of soft X-rays scattering at the C and O K-edge offers chemical sensitivity and can give unique information on the structure of di- and tri- block-copolymers [1-3]. Among block-copolymers, sulfur containing polymers are quite interesting for energy applications, thus the development of X-ray scattering and absorption techniques at the sulphur edge is extremely interesting.
In this contribution I will discuss based on some recent results the possibility to use hard, intermediate and soft X-rays to study the structure over different length scales for block-polymers and nano-structured materials. Indeed, the importance to gather data at hard and intermediate energies is even more evident when inorganic (nano) structures containing both high and low Z atoms are studied, i.e. nanostructures for photonic and catalysis applications.
[1] Virgili, J. M., Tao, Y., Kortright, J. B., Balsara, N. P., & Segalman, R. A. (2007). Analysis of order formation in block copolymer thin films using resonant soft X-ray scattering. Macromolecules, 40(6), 2092-2099.
[2] Wang, C., Lee, D. H., Hexemer, A., Kim, M. I., Zhao, W., Hasegawa, H., ... & Russell, T. P. (2011). Defining the nanostructured morphology of triblock copolymers using resonant soft X-ray scattering. Nano letters, 11(9), 3906-3911.
[3] Pavlopoulou, E., Anastasiadis, S. H., Kortright, J. B., Bras, W., & Portale, G. (2010, November). Investigation of the Micellization in Thin Films Using Resonant Soft X-Ray Scattering. In IOP Conference Series: Materials Science and Engineering (Vol. 14, No. 1, p. 012017). IOP Publishing.
Dr. Tod Pascal, Molecular Foundry, Lawrence Berkeley National Lab, Berkeley, CA
Topic: Electronic and structural parameters that affect sulfur K-edge X-ray absorption spectra: first-principles understanding of Li-S battery chemistry
Dr. Armin Wagner, Diamond Light Source, UK
Topic: Anomalous phasing of native macromolecular crystals at long wavelengths
Abstract: Over the past two years single-wavelength anomalous dispersion (SAD) phasing experiments exploiting the small signals from sulphur or phosphorous have solved increasingly complex structures from native macromolecular crystals in the wavelength range between 1.7 and 2.0 angstrom. As sulphur and phosphorus are present in proteins and nucleic acids no additional labelling is needed to apply this technique. Extension of the wavelength range beyond 2 A to increase the anomalous signals is difficult with current beamline setups. Therefore the long-wavelength MX beamline I23 has been designed for optimal usage of longer wavelengths towards the sulphur K-edge (2.47KeV). It will operate in a vacuum environment with a large curved area detector. It is currently in its commissioning phase towards first users at the end of 2014. The presentation will focus on the potential scientific opportunities and present the current status of the beamline project.
Jan Wernecke, Physikalisch-Technische Bundesanstalt, Germany
Topic: GISAXS below 4 keV: Tools and applications
Abstract: GISAXS below 4 keV offers many interesting applications, for example anomalous or resonant scattering at absorption edges of light elements (silicon, phosphorus, sulphur, chlorine, ...) or scattering contrast matching. However, photon energies below 4 keV pose a number of (technical) challenges, most notably the availability of suitable area detectors due to air scattering and strong absorption in vacuum windows.
I will present some technical details of a windowless in-vacuum PILATUS 1M detector, which was developed in a cooperation of the Physikalisch-Technische Bundesanstalt (PTB) and Dectris Ltd., that makes imaging down to 1.75 keV possible. The detector was radiometrically and geometrically characterized in a traceable manner and is in regular operation at our four crystal monochromator beamline in the PTB laboratory at BESSY II in Berlin.
Presented application examples are resonant GISAXS measurements at the S and Cl absorption K-edges on organic photovoltaic systems and thermoelectric polymer films. Another interesting technique that becomes possible at low photon energies is the scattering contrast matching of (polymer) thin films and the substrate. I will also show depth-resolved GISAXS with scattering contrast matching at the silicon K-edge (1839 eV) to study structural changes in annealed PS-b-P2VP block copolymer thin films along the film thickness. The study revealed a significantly reduced ordering at the surface of the annealed film, while order is preserved towards the substrate interface
Acknowledgement:
Deborah Smith and Susan Bailey (ALS; conference organizers);
Travel info:
(1) ALS LBNL address:
1 cyclotron road, Berkeley, CA 94720
(2) nearby airport
San Francisco international airport, (SFO)
It is about 25.5 miles away from LBNL
(3) from SFO to LBNL
by car (30-60 min depending on traffic)
by shared shuttle (~$35)
(e.g. supershuttle
or BART (~$10)
If take BART, get off at Berkeley downtown station
from Berkeley downtown station to LBNL
LBNL shuttle bus, to ALS or LBL guest house (shuttle schedule below)
http://www2.lbl.gov/Workplace/Facilities/Support/Busses/all_routes.html
(4) lodging
LBL Guest house is on site, walking distance to ALS, please make reservations ASAP since it will be gone quickly.
http://www.berkeleylabguesthouse.berkeley.edu/
there are many hotels in Berkeley, e.g.