SLAC National Accelerator Laboratory
Showing 101-150 of 1,934 Results
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Sandra Beauvarlet
Visiting Physicist, SLAC National Accelerator Laboratory
BioPostdoctoral Researcher and Visiting Scholar specialized in ultrafast laser-matter interaction.
My PhD research focused on investigating molecular chirality through the interaction of electrons with laser pulses at the femtosecond and attosecond timescale via the PhotoElectron Circular and ELliptical Dichroism (PECD and PEELD). This finality demanded several laser source and metrology developments such as : (i) Performed frequency conversion up to the 4th harmonic of an Amplitude System Tangerine Yb-fiber short pulse laser at 1030 nm and used its Optical Parametric Amplifier to generate short pulse continuously tunable source. (ii) Engineered various polarization schemes ranging from the simplicity of 1 color pulse circularly polarized to the complexity of 2 non-colinear sets of two-color orthogonally polarized pulses with an active sub-cycle delay stabilization. (iii) Contributed to low-loss capillary-based visible pulse compression at the Yb-fiber laser's second harmonic (515nm) and built the FROG instrument to measure sub-15 fs pulses. (iv) Build and tuned UV attosecond table-top sources using the process of High Harmonic Generation (HHG). (v) Developed 2D and 3D electron spectroscopy instruments (VMI, COLTRIMS) and algorithmS notably using Fourier Transform, Abel inversion, Radon transform...
My postdoctoral research focus extended to the physics of X-ray Free Electron Laser (XFEL) at LCLS and broadened to the use of these X-ray attosecond pulses to drive ultrafast dynamics in atoms and molecules. My current work and interest focus on electron/ion spectroscopy (MBES), absorption spectroscopy and X-ray diffraction probing Charge Migration, Ring Opening, Isomerization, Conical Intersections, Raman Scattering ... but also enhance the collected data quality using variability to our advantage through Covariance approaches and ghost imaging based Machine Learning procedure to improve attosecond spectroscopy. -
Surjendu Bhattacharyya
Research Assoc-Experimental, SLAC National Accelerator Laboratory
BioI am currently a Research Associate at SLAC’s LCLS SRD Chemical Science Department. My research focuses on time-resolved dynamics in the gas phase, with a particular interest employing novel experimental techniques to investigate the dynamics of molecules, radicals, and ions. These techniques include Coulomb explosion imaging, MeV electron diffraction (MeV-UED), X-ray scattering, X-ray absorption, and photoelectron spectroscopy. This work aims to improve the fundamental understanding of energy, environmental, biological, and atmospheric processes.
I am currently adapting a pyrolysis source to a time-of-flight spectrometer to perform time-resolved studies of radicals using UV, high harmonic generation (HHG), and X-rays. Additionally, I plan to integrate the pyrolysis setup with MeV-UED to investigate structural molecular dynamics through diffraction measurements. -
Alex Bien
Accel System Operator I, SLAC National Accelerator Laboratory
BioI am a 2022 graduate with a B.S. in physics from the University of Maryland at College Park, and I currently operate the world's longest and most powerful linear particle accelerator administrated by Stanford University under the direction of the US Department of Energy. Here I interface directly with the machinery, controls, and safety systems for three linear accelerator facilities: FACET-II where electron-pair beams are shot thru hot plasma to study novel wakefield acceleration techniques, LCLS where coherent x-rays of very high energy (and inversely low wavelength) probe deep into matter for imaging at atomic scales, and LCLS-II where commissioning is underway to produce a much more powerful megahertz rep rate superconducting beam that can leverage the same XFEL mechanism to (instead of just taking snapshots) also resolve the dynamics of chemical reactions in situ.
