Time-Stabilized Ultrafast Electron Diffraction and Microscopy

Statement of the problem or situation that is being addressed: Ultrafast Electron Diffraction and Microscopy systems can provide snapshots of a dynamic system on a time scale of femtoseconds. It can be used to study: ultrafast phenomena in condensed matter physics; biological processes such as unfolding and re-folding of proteins; and the kinetics and mechanisms involved in inflammation, oxidative stress and antioxidant/anti- inflammatory drug action. A relatively inexpensive and compact system can allow greater access and increased data security for users. Statement of how this problem or situation is being addressed: A single-cavity RF photocathode gun accelerates electrons to around 1 MeV, after which, they are taken through an alpha magnet designed for a constant time-of-flight between the photocathode and sample chamber independent of small fluctuations of beam energy. The project will eventually establish a user facility at Northern Illinois University. What is to be done in Phase I? Phase I of this project will include the simulation and optimization of the beam evolution in the system including alpha magnet and focusing solenoids. We will also evaluate the choice of photocathode emitter, design any magnetic elements, specify and design the sample chamber and diagnostics system, and specify the laser system. Commercial Applications and Other Benefits: The proposed Ultrafast Electron Diffraction microscopy device will create a new center for the study of ultrafast phenomena. It will help to educate students, and it will likely be used in the thesis work of one student in the particle accelerators field, one in chemistry, and one in engineering/nano-technology. The proposed device, or adaptations of it, will be offered for sale to commercial customers. This will put the technology into the hands of many additional research groups and companies. The proposed system may also be purchased by a company wishing to perform the research in private as a way of protecting trade secrets or to guarantee confidentiality. Key Words: Ultrafast Electron Diffraction, electron gun, alpha magnet, photoinjector Summary for Members of Congress: Ultrafast Electron Diffraction microscopy can provide snapshots of a dynamic system on a time scale of femtoseconds. It can be used to study: ultrafast phenomena in condensed matter physics; biological processes such as unfolding and re-folding of proteins; and the kinetics and mechanisms involved in inflammation, oxidative stress and antioxidant/anti-inflammatory drug action. A relatively cheap and compact system is being developed that can allow greater access and increased data security for users.