We have positions available for motivated PhD students with a background in one of more of the fields of photon science, optics, experimental science, or signal processing.  A fundamental knowledge in laser science or X-ray physics would be advantageous.  A basic knowledge of English is required.

We have specific PhD projects open to address the challenges of single-particle diffractive imaging and to advance the field of ultrafast coherent diffractive imaging. These projects include:

1. •Development of new phase-retrieval and data assembly methods to determine the three-dimensional structure of a stream of randomly oriented but reproducible objects, from their coherent X-ray diffraction patterns.  This project has both experimental and computational components.
   

2. •Development of novel holographic and interferometric X-ray imaging methods to image particles, biological cells, and materials under with extremely intense X-ray pulses, to obtain images superior to achievable by today’s X-ray microscopy.  This will be applied to imaging ultrafast events, such as the laser ablation of materials.
   

3. •Controlling the trajectories and orientations of particle streams and molecules using synchronized laser beams or other radiation, to carry out ultrafast X-ray diffractive imaging on these systems to obtain movies of molecular motions.
   

4. •Development of X-ray optics for focusing intense FEL pulses.  These are based on multilayer and thin-film techniques, and optimization requires the development of novel wavefront control and measurement techniques for coherent X-rays.
   

5. •Ultrafast nanocrystallography.  Powder patterns can be collected from streams of submicron protein crystals at synchrotron sources.  Using XFEL pulses these same samples can be used to collect single-crystal data.  Experimental and computational methods must be developed to merge this data to determine 3D atomic structures.
   

6. •Development of ultrafast holography to measure the interaction of particles with intense X-ray pulses. It has been suggested that the imaging of molecules could be carried out by delaying their destruction in the X-ray pulse, with the use of a sacrificial “tamper” layer.  Holographic methods can be adapted to the X-ray regime to directly see “before” and “after” images with sub-femtosecond time resolution.
   

7. •Development of correlation X-ray imaging techniques to extract 3D structural information from diffraction of a gas of completely randomly oriented objects.  This would extend the field of small-angle X-ray scattering (SAXS) and be used in the study of protein folding dynamics.
   

Requirements: We are looking for motivated PhD and diploma/Masters candidates with a background in experimental physics or chemistry, photon science, Fourier optics, synchrotron radiation research, or a closely related field.

Further information: Salary and benefits are as determined for public service organizations in Germany.  The thesis supervision is through the University of Hamburg.  Women are explicitly encouraged to apply.  If you are interested in this work please contact Prof. Henry Chapman (henry.chapman@desy.de) or send a CV and academic achievements.

Start Date: 15.1.2009 or as soon as possible

Duration: 3 years