# Presentation: 398077

## Understanding typical users for this instrument

- _Graduate 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

_**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

- 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:

##  Standard Sample mount 

- 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):360o    range, Resolution / Repeatability 0.0005o
-  Chi:  360o  range, Resolution / Repeatability 0.0005o.
_**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

## Sample diffractometer versions

_**Transmissive Geometry**_

- 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)+3+3+3 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

_**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.