Understanding typical users for this instrument Graduate studentGraduate student –not an X-ray expert but wants to make a spatially resolved measurement; probably in communication with a more experienced professor. Busy Expert –Swoops in at 9.01 am, takes data rapidly and zooms out to beat the rush hour. Cutting edge experimenter –Drives up with a truck of experimental equipment to spend a week of beam time, but needs little help. –Resident scientist (lives at the beamline)

Diffractometer Design points Easy to use, robust –Designed well,and supported; e.g. beam focussing is fast. Good reciprocal space access Modular –Optics choices: KB, capillaries, CRL –Sample manipulation: Reflection, transmission, environment –Detectors: Area (CCD) detector, point detector w/ analyzer crystal, image plate,... Simultaneous Fluorescence detection Computerized alignment (Optical,fluorescence) Remote operation Continually evolving –How does one do practical diffraction with spatial resolution < 100nm? –Hard X-ray imaging

Put the optics and sample motions on the same bar and mechanically vibration isolated from the world and detector motions. –Note sample motion and detector motions are disconnected. Temperature stabilization Overall Schematic

X-ray Optics details Kirkpatrick-Baez –Achromatic within a bandpass. Capillaries –Large divergence, small working distance, good for powder Refractive lenses (CRL) –Dispersive(?); focal point shifts with energy. Others Design to allow easy choice between:

Overall X,Y,Z Chi rotation Phi rotation Sample X,Y,Z, Coarse and Fine Not shown: Tilt(2) +rotation to get a sample feature to line up with mechanical translations Standard Sample mount

Sample Motion Specifications Sample Translations Crude XYZ : 25mm range, with 1micron steps Fine XYZ: Piezo, 200micron range with 5nm resolution Sample Rotations Theta(th):360 o range, Resolution / Repeatability o Chi: 360 o range, Resolution / Repeatability o. Alignment Translations This entire assy has its own alignment table: X,Y,Z ranges 50mm with 50micron resolution. Off the shelf parts, should operate down to 0.1micron with patience. Encoders/laser interferometry for good recovery/remote operation

Reflective Geometry Transmissive Geometry Sample diffractometer versions Typical sample is a film on a “thick” substrate “Thin” sample

Build to match sample problem; it is too expensive and cumbersome to buy stages that carry very heavy items. By restricting some of the motions one can still do the experiment. Will need “spare parts” to be able to do this Issues with sample environment Some examples of possible sample environments Low temperature Thermal cycling Mechanical loading (Tensile, bending,thermal,X20) UHV

Very high resolution questions The sample will be sitting on order of 3+(2) sets of ball bearings; too many. See how far we get with the off the shelf setup, but be thinking and designing for nanometer scale operation. For example a)minimize as many mechanical degrees of freedom with computer control. b) Move and clamp. (Does computerized clamping exist in the right profile?)

Visual Feedback Computer interfaced cameras, selectable input. Helps on crash recovery. One microscope objective focussed and fixed on the sample center of rotation (COR),with a 1mm field of view. Allows you to easily steer the diffractometer COR to the beam. Allows you to move the sample around and see what you are scattering from Allows the height adjustment. Images here should be available as input data to the SPEC. Beam find/spectroscopy. If you can adjust/zoom in with a 10micron field of view you could refocus optics/slits. One camera with large field of view sitting on table but also looking at COR. Other inexpensive cameras as required to trace the X-ray path with phosphor flags. Good camera optics on a stage with YAG to do rapid focussing/slits. (Separate stage?)

Detector arm with 2 degrees of freedom Gives good reciprocal space access Switch between Area detector (CCD) and point detector easily Translation stage to vary the CCD to sample distance (resolution) Will be able to support typical CCD weight. Point detector will typically be a scintillator with an analyser xtal.