Wave-guided X-ray Tomographic Microscope

Project Summary Abstract X ray microscopy systems with resolution in the tens of nanometers are enabling significant advances in studies of cellular structure and functionprotein crystallography and many other fieldsThe reliance on synchrotron sources of x ray fluxhoweverlimits the scope of the work that can be done and the access many groups have to this powerful toolAs offor examplethere were only four cryo SXT microscopes installed and operational at synchrotrons worldwideAlternative sources such as liquid metal jetLMJand miniature synchrotrons are advancing but still have limited brightnessfor long image acquisition timesand they too require rotation of the subject for tomographic imagingThe proposed wave guided x ray tomographic microscopeWXTMwill combine recent advances in waferbased x ray waveguides developed at the University of Gottingennow used with synchrotronswith a novel electron beam impact source called the forward flux channelFFCdeveloped at StellarrayA tapering optic will connect these two components for efficient coupling of exit beams to the acceptance angles of the waveguide inputIn the FFC primary sourcex rays are generated by e beams accelerated into holes or slits in a metal anode targetfor a kind ofD anode geometry that will produce an extended source of sheet beam fluxThis is ideally suited to coupling to a long line of entrances to high aspect ratio waveguide channels that will be combined to exit anm or smaller exit at the other end of the waveguideFFC sources efficiently use nearly all the e beamsupplied by lateral cold cathode edge emittersand spread the beam over a very large anode surface area so high power can be input to the sourceWafer based waveguides have been developed at Gottingen that can transmit up toof the flux input and compress the beams to high ordersThe specific aims of Phase I are to conduct detailed parametric studies of the primary sourceoptical coupling and waveguide combining branch patterns for an initial source designand de risk the major new componentsthe FFC and the waveguide chipby process developmentfabrication and testPhase II will build on this work to make the full x ray source and a prototypeD projection microscope with at least an order of magnitude higher flux intensity and brightness than LMJ sourcesto approximate second generation synchrotronsThe WXTM source will be small and light enough for rotating or stationary tomography systems with no subject rotationor for phase contrastbuilding on the Phase II platformThe target energy for the project will bekeV using Cu anodesbut other sources can be developed for the water window or for harder beam imagingThe outcome of the project will be a versatile new x ray microscopy tool that will make this imaging modality widely accessible to research groups and commercial customersWXTM will be the workstation to the synchrotron supercomputerlagging behindbut spreading the benefits x ray microscopy more widely and into new areas Project Narrative X ray microscopy has emerged as an essential tool in cellular imaging studies including structureabnormal cell growth and genetic changesprotein functionality and other subjectsSynchrotron x ray beams with focusing optics are mainly used now for high brightness providing resolution in tens of nanometers and acquisition times fast enough for tomographic imaging by rotating the sampleThe proposed wave guided x ray tomographic microscopeWXTMwill combine several innovationsincluding an extended x ray source based on aforward flux channelD anode and nano scale x ray waveguide optics made on silicon wafersto make a high brightnessbench top x ray microscope with nano scale resolution that can be used inDrotating tomography and stationary tomography systems