david fritz xpp [email protected] june 17, 2008 1 the x-ray pump-probe instrument...
Post on 21-Dec-2015
213 views
TRANSCRIPT
David Fritz
XPP Instrument [email protected]
June 17, 20081
The X-ray Pump-Probe Instrument
Instrument Scientist: David Fritz
Second Scientist: Marc Messerschmidt
Lead Engineer: J. Brian Langton
Designer: Jim Defever
Designer: Jim Delor
David Fritz
XPP Instrument [email protected]
June 17, 20082
Outline
Brief Instrument Overview
Sample Goniometer System
Detector Mover System
Optics Table Design
Conclusion
David Fritz
XPP Instrument [email protected]
June 17, 20083
XPP Experimental Techniques
Time-Resolved X-ray Diffraction (TRXD)
Time-Resolve Diffuse Scattering (TRDS)
Time-Resolved Protein Crystallography (TRPX)
X-ray Emission Spectroscopy (XES)
Small Angle X-ray Scattering (SAXS)
Optical Probing of X-ray Transients
* The instrument budget is not sufficient to provide capability to all techniques
David Fritz
XPP Instrument [email protected]
June 17, 20084
XPP Instrumentation Categories
X-ray BeamPreparation (spatial profile, intensity, spectrum, repetition rate)
Delivery to sample
Characterization (spatial profile, intensity, arrival time)
Optical BeamCreation
Preparation (spatial profile, intensity, spectrum, repetition rate, temporal profile)
Delivery to sample
Characterization (spatial profile, intensity, spectrum, temporal profile)
Sample EnvironmentOrientation & Positioning
X-ray Detection
David Fritz
XPP Instrument [email protected]
June 17, 20086
XPP Instrument Location
XCS
AMO(LCLS)
CXI
XPPEndstation
Near Experimental Hall
Far Experimental Hall
X-ray Transport Tunnel
David Fritz
XPP Instrument [email protected]
June 17, 20088
Detector Mover – Design Goals
Flexibility to accommodate a wide variety of sample environments
Capable of orienting small samples (~ 50 μm) over a wide range of reciprocal space
Sphere of confusion < 30μm
Open access to allow close proximity laser optics
No interference with direct beamline while in monochromatic mode
David Fritz
XPP Instrument [email protected]
June 17, 20089
Sample Goniometer – Tilt Platform
400 mm x 400 mm top surface
± 5°angular range of arc segments
Large load capacity (>> 50 kg)
200 mm working distance
David Fritz
XPP Instrument [email protected]
June 17, 200811
Sample Goniometer – Kappa Configuration
David Fritz
XPP Instrument [email protected]
June 17, 200812
Detector Mover – Design Goals
Operate in both interaction points 10 cm – 100 cm sample to detector distance in forward-scattering upper hemisphere quadrant10 cm – 50 cm sample to detector distance in back-scattering upper hemisphere quadrantRepeatable position the XPP detector pixels to a fraction of the pixel size Definitively know the position of all detector pixels to a fraction of the pixel size
David Fritz
XPP Instrument [email protected]
June 17, 200815
Detector Mover – Concept
6-axis Industrial Robot
Load capacity (> 20 kg)
± 50 µm repeatability
Floor or ceiling mountable
No counterweights Remotely variable sample to detector distance
Remote control of detector clocking angle
David Fritz
XPP Instrument [email protected]
June 17, 200816
Detector Mover – Path Forward
Engineering and manufacturing will be broken up into 3 work packages
Statement of work 1Verify that a industrial robot has the capability of meeting motion requirements
Statement of work 2Create a concept for integrating robot into the XPP instrument
Statement of work 3Manufacturer, install, test and integrate system
David Fritz
XPP Instrument [email protected]
June 17, 200817
Detector Mover – SOW 1
Test 1 – Spherical motion and pointingSystem is capable of moving the detector about a spherical surface of a user defined radii while pointing the detector at the interaction region
Test 2 – RepeatabilityMeasure repeatability and hysterisis of system
Test 3 – Detector Clocking AngleMeasure how well the clocking angle can be controlled
Test 4 – Stability Measure long term (~ hours) motion drift for various fixed positions
Test 1
Test 2
David Fritz
XPP Instrument [email protected]
June 17, 200818
Detector Mover – SOW 2
Concept for integrating system into XPPRobot arm mounting
Reach requirements can be met without intruding into mechanical stay clear zones
Safety system
David Fritz
XPP Instrument [email protected]
June 17, 200819
Optics Support Table – Design GoalsRepeatable position optics in two operating positions (mono, direct)
Initial beam based alignment is expected for each position but the desire is to have a configuration file loaded for each operating mode without the need for alignment
Stably support X-ray optics and diagnosticsDesign logic:
Optical axis will be defined by XPP slitsX-ray optics and interaction point can drift together on the order of 100 µm with minimal impact
However, the diffractometer thermal drift is an unknownIt was determined that it was best to design a support table that fixes the position and alignment of the optical elements to the highest extent reasonably achievableThis reduces misalignment issues to a one dimensional problem
Design goals in priority order:Stability of optics with respect to each other over short and long term periodsAbsolute position stabilitySlits are the gold standard and need to be the most stable of all elements
David Fritz
XPP Instrument [email protected]
June 17, 200820
Optics Support Table – Case Studies
Analyzed component displacement due to bowing of support structure for a 2° F temp changeAnalyzed global displacement of entire structure due to 2° F thermal expansionLarge granite surface plate with a low profile strongback was best option
Themalization time constant of the granite is many daysHowever, the drawback is the rigging effort – must be moved in through the FEH
David Fritz
XPP Instrument [email protected]
June 17, 200821
Optics Support Table – Design
Strongback has been split into two sections to minimize bowing and to prevent system overconstraintsStrongback is strategically tied down to rails near locations of slits
David Fritz
XPP Instrument [email protected]
June 17, 200822
Questions for the Committee
Is the sample goniometer design optimized form the scientific goals of the instrument?
Are the sample mover design requirements reasonable?
Does the sample mover path forward seem reasonable?
Is the design logic of the optics support table valid?
Any other concerns/comments?