SLAC National Accelerator Laboratory
Showing 81-90 of 90 Results
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Joachim Stöhr
Professor of Photon Science, Emeritus
BioEducation:
1968 Vordiplom in Physics, Bonn University, Germany
1971 M.S. in Physics, Washington State University, USA
1974 Dr. rer. nat. in Physics, TU München, Germany
Professional History:
Scientist at Lawrence Berkeley Laboratory (1976-77)
Senior Research Associate at Stanford Synchrotron Radiation Laboratory (1977-81)
Senior Staff Physicist at Exxon Research and Engineering Company (1981-85)
Research Staff Member at IBM Almaden Research Center (1985-89)
Manager, Department of Condensed Matter Science, IBM ARC (1989-91)
Manager, Department of Magnetic Materials and Phenomena, IBM ARC (1991-94)
Manager, Synchrotron Radiation Project, IBM ARC (1994-95)
Research Staff Member at IBM ARC (1995-99)
Professor of Photon Science, Stanford University (2000 – 2017)
Deputy Director, Stanford Synchrotron Radiation Lightsource (SSRL) (2000-2005)
Director, SSRL (2005-2009)
Director, Linac Coherent Light Source (LCLS) (2009-2013)
Professor Emeritus (2017 – present)
Fellowships, Awards, Honors:
Fulbright Scholarship 1969-70
Postdoctoral Scholarship from Deutsche Forschungsgemeinschaft 1975-76
Fellow of the American Physical Society since 1988
Adjoint Professor in Physics at Uppsala University, Sweden (1993-2000)
Consulting Professor at Stanford Synchrotron Radiation Laboratory (1994-1999)
IBM Outstanding Technical Achievement Award 1997
Hofstadter Lecture, Stanford University, 2010
Davisson-Germer Prize 2011 in Surface Physics from American Physical Society
Ångstrom Lecture, Uppsala University, 2017
Summary of Scientific Work:
My early scientific research focused on the development of x-ray based surface techniques, especially surface EXAFS and NEXAFS, and their use for the determination of the geometric arrangement and bonding of atoms, molecules and thin organic films on surfaces. This work is summarized in my review article “SEXAFS: Everything you always wanted to know about SEXAFS but were afraid to ask” (in X-Ray Absorption: Principles, Applications, Techniques of EXAFS, SEXAFS and XANES, Edits. D. Koningsberger and R. Prins, Wiley, 1988) and my 1992 book “NEXAFS Spectroscopy” (Springer).
My later research focused on magnetic materials and phenomena, in particular the study of magnetic thin films, interfaces and nanostructures, and their ultrafast dynamics by use of forefront x-ray techniques. This work forms the foundation of my 2006 book (with H. Siegmann) entitled “Magnetism: From Fundamentals to Nanoscale Dynamics” (Springer).
With the advent of x-ray free electron lasers (XFELs) around 2010 my research increasingly focused on the description of x-rays and their interactions with matter within modern quantum optics, leading to my 2023 book “The Nature of X-Rays and their Interactions with Matter”.
In total I have written 3 books, 10 review articles in the form of book chapters and about 250 scientific Journal publications. I hold 5 patents and have given more than 150 invited talks at international scientific conferences, about 100 colloquia at Universities and Scientific Research Institutions, and 3 public lectures on the topic of magnetism and x-ray free electron lasers.
More information on my career, research, students and postdocs is given on my Stanford website: https://stohr.sites.stanford.edu/ -
Hirohisa A. Tanaka
Professor of Particle Physics and Astrophysics
Current Research and Scholarly InterestsParticle physics and astrophysics, neutrino properties, dark matter
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Sami Gamal-Eldin Tantawi
Professor of Particle Physics and Astrophysics, Emeritus
BioFor over a decade I have advocated for dedicated research efforts on the basic physics of room temperature high gradient structures and new initiatives for the associated RF systems. This required demanding multidisciplinary collaboration to harness limited resources. The basic elements of the research needed to be inclusive to address not only the fundamentals of accelerator structures but also the fundamentals of associated technologies such as RF manipulation and novel microwave power sources. These basic research efforts were not bundled with specific developments for an application or a general program. The emerging technologies promise a broad, transformational impact.
With this underlying philosophy in mind, in 2006 the US High Gradient Research Collaboration for which I am the spokesman was formed. SLAC is the host of this collaboration, which comprises MIT, ANL, University of Maryland and University of Colorado, NRL and a host of SBIR companies. This led to the revitalization of this research area worldwide. The international collaborative effort grew to include KEK in Japan, INFN, Frascati in Italy, the Cockcroft Institute in the UK, and the CLIC team at CERN.
This effort led to a new understanding of the geometrical effects affecting high gradient operations. The collaborative work led to new advances in understanding the gradient limits of photonic band gap structures. Now we have a new optimization methodology for accelerator structure geometries and ongoing research on alternate and novel materials. These efforts doubled the usable gradient in normal conducting high gradient linacs to more than 100 MV/m, thus revitalizing the spread of the technology to other applications including compact Inverse Compton Scattering gamma-ray sources for national security applications, and compact proton linacs for cancer therapy. -
Christopher John Tassone
Associate Professor (Research) of Photon Science
BioChristopher J. Tassone, PhD is the Associate Lab Director for the Energy Sciences Directorate. His scientific interests lie in the development and characterization of advanced materials for energy. Dr. Tassone’s research addresses critical challenges in energy transition materials, plastics production, and catalysis, with the goal of improving energy technologies and utilizing domestically secure feedstocks. He is an expert in synchrotron-based X-ray scattering techniques, which he uses to probe the time resolved structure of materials as they are synthesized, and how they evolve under operation. He compliments this focus on developing operando and in-situ methods, with the development and application of machine learning for data interpretation and experimental steering. Through this work, Dr. Tassone helps accelerate the discovery of innovative materials for energy and catalysis.
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Caterina Vernieri
Assistant Professor of Particle Physics and Astrophysics
BioCaterina Vernieri received her PhD on the CMS experiment from the Scuola Normale Superiore in Pisa, Italy, in 2014 and then moved to Chicago for a postdoctoral fellowship at the Fermi National Accelerator Laboratory. She joined SLAC in 2018 as a Panofsky Fellow and moved to the ATLAS experiment, and in 2022 she became Assistant Professor.
Throughout this time, she has been devoted to studying the Higgs boson using data from the LHC. She co-led the group in the CMS experiment studying the Higgs decay to b quarks at the time that this important decay process was finally discovered in the data. At SLAC, Caterina is working with the ATLAS experiment at the LHC with a focus on Higgs physics. She is responsible for the integration activities at SLAC of the new ATLAS Pixel Inner Tracker detector.
She was also co-convener of the group on Higgs boson properties in the US national study of the future of particle physics. -
Soichi Wakatsuki
Professor of Photon Science and of Structural Biology
Current Research and Scholarly InterestsUbiquitin signaling: structure, function, and therapeutics
Ubiquitin is a small protein modifier that is ubiquitously produced in the cells and takes part in the regulation of a wide range of cellular activities such as gene transcription and protein turnover. The key to the diversity of the ubiquitin roles in cells is that it is capable of interacting with other cellular proteins either as a single molecule or as different types of chains. Ubiquitin chains are produced through polymerization of ubiquitin molecules via any of their seven internal lysine residues or the N-terminal methionine residue. Covalent interaction of ubiquitin with other proteins is known as ubiquitination which is carried out through an enzymatic cascade composed of the ubiquitin-activating (E1), ubiquitin-conjugating (E2), and ubiquitin ligase (E3) enzymes. The ubiquitin signals are decoded by the ubiquitin-binding domains (UBDs). These domains often specifically recognize and non-covalently bind to the different ubiquitin species, resulting in distinct signaling outcomes.
We apply a combination of the structural (including protein crystallography, small angle x-ray scattering, cryo-electron microscopy (Cryo-EM) etc.), biocomputational and biochemical techniques to study the ubiquitylation and deubiquitination processes, and recognition of the ubiquitin chains by the proteins harboring ubiquitin-binding domains. Current research interests including SARS-COV2 proteases and their interactions with polyubiquitin chains and ubiquitin pathways in host cell responses, with an ultimate goal of providing strategies for effective therapeutics with reduced levels of side effects.
Protein self-assembly processes and applications.
The Surface layers (S-layers) are crystalline protein coats surrounding microbial cells. S-layer proteins (SLPs) regulate their extracellular, self-assembly by crystallizing when exposed to an environmental trigger. We have demonstrated that the Caulobacter crescentus SLP readily crystallizes into sheets both in vivo and in vitro via a calcium-triggered multistep assembly pathway. Observing crystallization using a time course of Cryo-EM imaging has revealed a crystalline intermediate wherein N-terminal nucleation domains exhibit motional dynamics with respect to rigid lattice-forming crystallization domains. Rate enhancement of protein crystallization by a discrete nucleation domain may enable engineering of kinetically controllable self-assembling 2D macromolecular nanomaterials. In particular, this is inspiring designing robust novel platform for nano-scale protein scaffolds for structure-based drug design and nano-bioreactor design for the carbon-cycling enzyme pathway enzymes. Current research focuses on development of nano-scaffolds for high throughput in vitro assays and structure determination of small and flexible proteins and their interaction partners using Cryo-EM, and applying them to cancer and anti-viral therapeutics.
Multiscale imaging and technology developments.
Multimodal, multiscale imaging modalities will be developed and integrated to understand how molecular level events of key enzymes and protein network are connected to cellular and multi-cellular functions through intra-cellular organization and interactions of the key machineries in the cell. Larger scale organization of these proteins will be studied by solution X-ray scattering and Cryo-EM. Their spatio-temporal arrangements in the cell organelles, membranes, and cytosol will be further studied by X-ray fluorescence imaging and correlated with cryoEM and super-resolution optical microscopy. We apply these multiscale integrative imaging approaches to biomedical, and environmental and bioenergy research questions with Stanford, DOE national labs, and other domestic and international collaborators. -
Risa Wechsler
Director, Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), Humanities and Sciences Professor and Professor of Physics and of Particle Physics and Astrophysics
BioRisa Wechsler is the Humanities and Sciences Professor and Professor of Physics in the School of Humanities and Sciences and Professor of Particle Physics & Astrophysics at SLAC National Laboratory. She is the Director of the Kavli Institute of Particle Astrophysics and Cosmology and the Center for Decoding the Universe and an Associate Director at Stanford Data Science. She is a cosmologist whose work investigates some of the most profound questions about our universe — how it formed, what it is made of, how it is structured, and what its future holds.
Her research focuses on understanding the evolution of galaxies, the large-scale structure of the universe, and the nature of dark matter and dark energy. She uses large numerical simulations, theoretical models, and the largest observed maps of the universe to explore these forces that shape the cosmos. Her recent work also investigates the formation and cosmological context of the Milky Way and probes dark matter through small-scale cosmic structure, and explores how data science and AI/ML can drive new understanding. Wechsler has played key leadership roles in major international collaborations including the Dark Energy Survey, Dark Energy Spectroscopic Instrument, and Rubin Observatory's Legacy Survey of Space and time, a decade-long survey that will reveal the dynamic universe in unprecedented detail. She is recently involved in the Via Survey, which will map the Milky Way at high precision to probe dark matter physics in new ways.
Wechsler is an elected member of the National Academy of Sciences and the American Academy of Arts and Sciences and a Fellow of the American Physical Society and the American Association for the Advancement of Science.
