About Lauren Mason

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So far Lauren Mason has created 103 blog entries.

STROBE solved a century-old scientific problem: Determining the 3D atomic structure of amorphous solids

Amorphous solids such as glass, plastics and rubber are ubiquitous in our daily life and have broad applications ranging from telecommunications to electronics and solar cells. However, due to the lack of any crystal-like long-range order, the traditional X-ray crystallographic methods for extracting the three-dimensional (3D) atomic arrangement of amorphous solids simply do not work. STROBE advanced atomic electron tomography to determine the 3D atomic positions and chemical species of an amorphous solid for the first time – with a stunning precision of 21 picometer. We found that instead of long-range order characteristic of crystals such as diamond, this amorphous metallic glass had regions of short- and medium-range order. Moreover, although the 3D atomic packing is disordered, some regions connect with each other to form crystal-like networks, which exhibit translational but no orientational order. Looking forward, we anticipate this approach will open the door to determining the 3D atomic coordinates of a wide range of amorphous solids, whose impact on non-crystalline solids may be comparable to the first 3D crystal structure solved by x-ray crystallography over a century ago.

Congrats to Franklin Dollar for Receiving the 2021 Tom Angell Fellowship Award for Outstanding Mentoring from UC Irvine

Awarded annually at the Office of Inclusive Excellence’s Mentoring for Achievement and Excellence event, this fellowship is intended to honor Tom Angell’s contributions as the UCI Graduate Counselor to graduate student wellness and retention. Awards are open to graduate students, faculty, and postdoctoral scholars. Award recipients demonstrate outstanding mentorship by going above and beyond their normal duties to create new opportunities to mentor UCI students.

IMEC CDI/Reflectometry Postdoc

Development of EUV-based coherent diffractive imaging for nanoscale device and interface inspection
Supervisor: Claudia Fleischmann
Co-supervisor: John Petersen

Summary:
The semiconductor industry relies on quantitative nanoscale imaging to inspect devices and components. This project will develop non-destructive, quantitative coherent diffraction imaging techniques compatible with modern and future semiconductor device architectures.

Motivation: Developing and realizing non-destructive, extreme ultraviolet, coherent diffractive imaging techniques suitable for semiconductor devices, interfaces, and materials.

Type of work: 70% computation, 20% experimental, 10% literature Requirements: coherent imaging, algorithm-based image reconstruction

Abstract:
The semiconductor industry routinely relies on nanoscale imaging methodologies for inspection and characterization of nanoscale features in devices and components. However, many of these metrologies are destructive, compatible with a limited sample set, or provide little or no chemical characterization. Extreme ultraviolet (EUV) coherent diffractive imaging (CDI) is a new approach for nanoscale imaging that utilizes diffraction patterns obtained from an impinging photo beam to reconstruct images of a sample via phase retrieval algorithms and is compatible with
a diverse sample set. CDI is non-destructive and, when performed with EUV light, can yield nanoscale, chemically specific images of transmissive and reflective samples (e.g., thin films/2D materials and device stacks, respectively). Imec’s AttoLab is a state-of-the-art metrology laboratory equipped with bright, coherent, tabletop sources which, working on the high harmonic generation (HHG) principle, emit attosecond pulses of tunable EUV light (56-10.3 nm). These sources will be used for performing CDI experiments in both reflection and transmission geometries, with achievable image resolutions of a few 10’s of nm (lateral) and sub-nm (axial). In addition to standard CDI geometries, this project will explore advanced CDI techniques such as ptychographic CDI and CDI coupled with reflectometry for quantitative chemical imaging with a large field of view. The grand challenge of coherent diffractive inspection is the reconstruction of the image from the diffraction patterns and due to the complexity of this process the main focus of this project will be on algorithm development using multithreading GPU processing and machining learning. Additionally, the immense versatility of the HHG EUV sources enables unexplored imaging modalities such as structured illumination CDI, single pixel detection, and time-resolved CDI with few-nm and few-femtosecond spatiotemporal resolution, each of which comes with a dedicated set of development needs. The results of this work will not only provide a yet-to-be-realized metrology pipeline for the semiconductor industry, but also pave the way for non-destructive, quantitative, nanoscale imaging of semiconductor components and devices, while also informing design strategy for device optimization.

We are seeking an outstanding candidate with enthusiasm for a mix of experimental and computational imaging science, with a PhD degree in physics, applied mathematics, data science, or an equivalent specialisation. The candidate should be able to work in an international environment and good written and oral communication skills in English are a prerequisite. Experience in experimental ultrafast optics, coherent imaging, and phase retrieval techniques is required.

Strategic motivation
Coherent Diffractive Imaging (CDI) using the newly installed EUV sources in the AttoLab is a completely new capability for the imec research programs. As a high-resolution, non-destructive and chemically specific imaging technique, CDI holds the potential to be a game-changer for defect, mask, wafer and device inspection. Under the umbrella of the cross-departmental AttoLab endeavour, impact across imec and into partner collaborations is assured, and the successful candidate will be able to carry out groundbreaking research in an inherently cross-functional team. At present, imec is lacking CDI expertise both on the application side as well as on the fundamental aspects. To excel in this research area, we need an experienced, skilled researcher (postdoc) in this field. The postdoc should fill in the missing knowledge gap, transfer knowledge to imec staff and assist us in boosting this line of research.

Atomic structure of a glass imaged at last

The positions of all the atoms in a sample of a metallic glass have been measured experimentally — fulfilling a decades-old dream for glass scientists, and raising the prospect of fresh insight into the structures of disordered solids. If the chemical element and 3D location of every atom in a material are known, then the material’s physical properties can, in principle at least, be predicted using the laws of physics. The atomic positions of crystals have long-range periodicity, which has enabled the development of powerful methods that combine diffraction experiments with the mathematics of symmetry to determine the precise atomic structure of these materials. Moreover, deviations from periodicity that create defects in crystals can be imaged with sub-ångström resolution. But these methods do not work for glasses, which lack long-range periodicity. Our knowledge of the atomic structure of glasses is therefore limited and acquired indirectly. Writing in Nature, Yang et al.1 report the experimental determination of the 3D positions of all the atoms in a nanometre-scale sample of a metallic glass.

Century-old problem solved with first-ever 3D atomic imaging of an amorphous solid

UCLA-led study captures the structure of metallic glass. Glass, rubber and plastics all belong to a class of matter called amorphous solids. And in spite of how common they are in our everyday lives, amorphous solids have long posed a challenge to scientists. Since the 1910s, scientists have been able to map in 3D the atomic structures of crystals, the other major class of solids, which has led to myriad advances in physics, chemistry, biology, materials science, geology, nanoscience, drug discovery and more. But because amorphous solids aren’t assembled in rigid, repetitive atomic structures like crystals are, they have defied researchers’ ability to determine their atomic structure with the same level of precision. Until now, that is. A UCLA-led study in the journal Nature reports on the first-ever determination of the 3D atomic structure of an amorphous solid — in this case, a material called metallic glass.

Do You Know the Way to Berkelium, Californium?

Heavy elements and a really powerful microscope help scientists map uncharted paths toward new materials and cancer therapies. Heavy elements known as the actinides are important materials for medicine, energy, and national defense. But even though the first actinides were discovered by scientists at Berkeley Lab more than 50 years ago, we still don’t know much about their chemical properties because only small amounts of these highly radioactive elements (or isotopes) are produced every year; they’re expensive; and their radioactivity makes them challenging to handle and store safely.

Congrats to Iona Binnie for Receiving an NSF Graduate Research Fellowship

The NSF GRFP recognizes and supports outstanding graduate students in NSF-supported STEM disciplines who are pursuing research-based master’s and doctoral degrees at accredited US institutions. The five-year fellowship includes three years of financial support including an annual stipend of $34,000 and a cost of education allowance of $12,000 to the institution.

Physics Education Research postdoc position at the University of Colorado

Applications are invited for a Postdoctoral Researcher in Physics Education in the Department of Physics at the University of Colorado Boulder (CU). The postdoc will work on a project titled “Development and Implementation of an assessment of student understanding of measurement and uncertainty in experimental physics.” This project aims to develop a scalable and validated assessment of students’ understanding of measurement uncertainty at the introductory level. Most of the research will be quantitative in nature and use item response theory.

The project is run jointly by Heather Lewandowski at the University of Colorado and Danny Caballero at the Michigan State University.

Candidates must have a Ph.D. in physics, physics education research, or closely related field. Prior experience with experimental physics research or physics education research is preferred. Prior experience with assessment development is preferred, but not required.

To apply for the position please send the following materials to lewandoh@colorado.edu.

  1. Cover letter that addresses the required and preferred qualifications described above, describes the applicant’s interest in joining the project, and answers the following questions:
    A) How do your previous experiences prepare you to work cooperatively and productively with colleagues and supervisors?
    B) In this postdoctoral research position, you will gain significant skills in physics education research. How do you envision those skills will be useful to you later in your career?
  2. CV with references listed.

The University of Colorado is an Equal Opportunity Employer committed to building a diverse workforce. We encourage applications from women, racial and ethnic minorities, individuals with disabilities and veterans. Alternative formats of this ad can be provided upon request for individuals with disabilities by contacting the ADA Coordinator at hr-ada@colorado.edu.

Postdoctoral Research Scholar Position Announcement

Norfolk State University’s Department of Engineering is seeking a candidate for a Postdoctoral Research Scholar position to conduct research in the area of biophotonics. The focus of this
research is on designing microfluidic devices to enable on-chip laser tweezers and traps and conducting surface enhanced Raman spectroscopy (SERS) for identifying breast cancer cells.
Successful candidate is expected to develop and demonstrate new approaches of system integration to improve accuracy, efficiency, scalability, and automation of the optofluidic sensing
platform and publish the findings in reputed journals and conference proceedings. The successful candidate will work in Computational Cardiac Engineering Lab at Norfolk State University in
Norfolk Virginia, and will be expected to collaborate across disciplines to ensure successful completion of research tasks.

Primary Responsibilities:
– Design a working SERS system for analyzing live biological cells. Conduct SERS-based experiments with various cell lines and analyze experimental data.
– Design and fabricate novel SERS substrates to amplify the Raman signals.
– Setup a dual-beam optical tweezer system for non-contact cell trapping and stretching.
– Perform Multiphysics modeling to configure the experimental setup and perform theoretical investigations.
– Develop, implement, and demonstrate new approaches to improve accuracy, efficiency, scalability, and automation of the optofluidic sensing system.
– Mentor graduate and undergraduate students; contribute in other ongoing research projects in the group.

Requirements:
– PhD in engineering or physical sciences in optics/photonics, biosensing, bioelectrics or related fields.
– Demonstrated expertise in Raman spectroscopy/SERS imaging, microfluidics and micro/nano-fabrication.
– Prior experience of micro/nano fabrication in cleanroom and handling of cleanroom equipment.
– Ability to quickly learn, analyze, and implement innovative biosensing applications/systems.
– Creativity and analytical skills.

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