Showing papers by "Joachim Schulz published in 2010"

Cryptotomography: reconstructing 3D Fourier intensities from randomly oriented single-shot diffraction patterns.

Abstract: We reconstructed the 3D Fourier intensity distribution of monodisperse prolate nanoparticles using single-shot 2D coherent diffraction patterns collected at DESY's FLASH facility when a bright, coherent, ultrafast x-ray pulse intercepted individual particles of random, unmeasured orientations. This first experimental demonstration of cryptotomography extended the expansion-maximization-compression framework to accommodate unmeasured fluctuations in photon fluence and loss of data due to saturation or background scatter. This work is an important step towards realizing single-shot diffraction imaging of single biomolecules.

Sacrificial tamper slows down sample explosion in FLASH diffraction experiments.

Abstract: Intense and ultrashort x-ray pulses from free-electron lasers open up the possibility for near-atomic resolution imaging without the need for crystallization. Such experiments require high photon fluences and pulses shorter than the time to destroy the sample. We describe results with a new femtosecond pump-probe diffraction technique employing coherent 0.1 keV x rays from the FLASH soft x-ray free-electron laser. We show that the lifetime of a nanostructured sample can be extended to several picoseconds by a tamper layer to dampen and quench the sample explosion, making <1 nm resolution imaging feasible.

Aerosol Imaging with a Soft X-Ray Free Electron Laser

Abstract: Lasers have long played a critical role in the advancement of aerosol science. A new regime of ultrafast laser technology has recently be realized, the world's first soft x-ray free electron laser. The Free electron LASer in Hamburg, FLASH, user facility produces a steady source of 10 femtosecond pulses of 7–32 nm x-rays with 1012 photons per pulse. The high brightness, short wavelength, and high repetition rate (> 500 pulses per second) of this laser offers unique capabilities for aerosol characterization. Here we use FLASH to perform the highest resolution imaging of single PM2.5 aerosol particles in flight to date. We resolve to 35 nm the morphology of fibrous and aggregated spherical carbonaceous nanoparticles that existed for less than two milliseconds in vacuum. Our result opens the possibility for high spatial- and time-resolved single particle aerosol dynamics studies, filling a critical technological need in aerosol science.

Short-pulse Laser Induced Transient Structure Formation and Ablation Studied with Time-resolved Coherent XUV-scattering

Abstract: The structural dynamics of short‐pulse laser irradiated surfaces and nano‐structures has been studied with nm spatial and ultrafast temporal resolution by means of single‐shot coherent XUV‐scattering techniques. The experiments allowed us to time‐resolve the formation of laser‐induced periodic surface structures, and to follow the expansion and disintegration of nano‐objects during laser ablation.

Single-shot femtosecond x-ray diffraction from randomly oriented ellipsoidal nanoparticles

Abstract: Coherent diffractive imaging of single particles using the single-shot "diffract and destroy" approach with an x-ray free electron laser (FEL) was recently demonstrated. A high-resolution low-noise coherent diffraction pattern, representative of the object before it turns into a plasma and explodes, results from the interaction of the FEL with the particle. Iterative phase retrieval algorithms are used to reconstruct two-dimensional projection images of the object from the recorded intensities alone. Here we describe the first single-shot diffraction data set that mimics the data proposed for obtaining 3D structure from identical particles. Ellipsoidal iron oxide nanoparticles (250 nm x 50 nm) were aerosolized and injected through an aerodynamic lens stack into a soft x-ray FEL. Particle orientation was not controlled with this injection method. We observed that, at the instant the x-ray pulse interacts with the particle, a snapshot of the particle's orientation is encoded in the diffraction pattern. The results give credence to one of the technical concepts of imaging individual nanometer and subnanometer-sized objects such as single molecules or larger clusters of molecules using hard x-ray FELs and will be used to help develop robust algorithms for determining particle orientations and 3D structure.

First automated production line for X-ray-LIGA (FELIG) is brought on line

Abstract: The project FELIG sets a milestone in X-ray-LIGA technology. The first automated LIGA production is brought online. The units have been implemented at the synchrotron source ANKA at Forschunszentrum Karlsruhe. They are linked via a conveyor line and controlled by a superior software system. Other process steps as resist technique have been partly automated. The whole process has been adapted to a wafer format of 6″. Automation and enlargement of formats will reduce production costs for LIGA components and help LIGA technique for industrial breakthrough.

Chapter 13 – Deep X-Ray Lithography

Abstract: Publisher Summary This chapter emphasizes the strengths of the manufacturing method and its main fields of application with examples taken from various groups worldwide, especially in micro-mechanics and micro-optics. The leading technology for the manufacturing of MEMS (micro-electric-mechanical systems) devices is silicon micro-machining with its various derivatives. Many applications of micro-systems have requirements in respect of materials, geometry, aspect ratio, dimensions, shape, accuracy of micro-structures, and number of parts that cannot be fulfilled easily by mainstream silicon-based micro-machining technologies. LIGA, a German acronym for Lithography (Lithographie), Electroplating (Galvanoformung), and Molding (Abformung) enables the highly precise manufacture of high aspect ratio micro-structures with large structural thickness ranging from hundreds to thousands of microns. These tall micro-structures can be produced in a variety of materials with well-defined geometry and dimensions, very straight and smooth side walls, and tight tolerances. LIGA technology is also well suited for the mass fabrication of parts, particularly in polymers. Many micro-systems benefit from the unique characteristics and advantages of the LIGA process in terms of product performance.