X-ray Correlation Spectroscopy Instrument Aymeric Robert XCS Instrument Scientist
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X-ray Correlation Spectroscopy Instrument Aymeric Robert XCS Instrument Scientist June 17-18, 2009 X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 1 1 Aymeric Robert aymeric@slac.stanford.edu Outline XCS Science XCS Goals and Physics Requirements XCS Instrument Overview X-ray Optics and Diagnostics MonochromatorS Diffractometer System Large Angle Detector Mover Hutch Facilities Operating Modes Work Breakdown Structure Early Science Instrument Scope Preliminary Instrument Design Review Summary X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 2 2 Aymeric Robert aymeric@slac.stanford.edu Science Team Specifications and instrument concept developed with the science team The XCS Team Leaders Brian Stephenson, ANL Gerhard Grübel, DESY Karl Ludwig, Boston University A workshop was held on October 17 2009 Applications of Coherent X-rays at the LCLS http://www-conf.slac.stanford.edu/coherence2008/default.asp X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 3 3 Aymeric Robert aymeric@slac.stanford.edu X-ray Photon Correlation Spectroscopy Coherent X-rays Coherent Scattering (Speckles) Speckles : scattering patterns produced by the coherent illumination of the sample XPCS : observation of the time-fluctuation of speckle patterns Characterization of the underlying dynamics of the system XPCS is independent of the scattering geometry (SAXS, Diff., GI-SAXS, Refl.,…) XPCS probes dynamical phenomena X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 First Hard X-ray Speckles 4 4 Aymeric Robert aymeric@slac.stanford.edu XPCS / Coherent Scattering at XFEL’s XPCS experiments on 3rd generation machines are strongly signal limited Limited coherent flux Beam damage Detector issues X-ray Free Electron Laser Sources Advantages New Challenges •Orders of magnitude larger coherent flux •Large Coherent Flux at any Es X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 •Pulsed source •Large number of coherent photons/pulse 5 5 Aymeric Robert aymeric@slac.stanford.edu XPCS / Coherent Scattering at XFEL’s Intensity autocorrelation function Dt Dt Dt Dt 4 3 2 1 1 2 3 4 Dt Dt Time-average Brilliance •1/(Rep. Rate) < tC< mach stab •Large Q’s accessible X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 6 6 Aymeric Robert aymeric@slac.stanford.edu Ultrafast XPCS with a Split and Delay Unit X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 7 7 Aymeric Robert aymeric@slac.stanford.edu Ultrafast XCS : Split & Delay No Dynamics (zero delay) Δt Change in Contrast ! Dynamics X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 8 8 Aymeric Robert aymeric@slac.stanford.edu Ultrafast XCS : Split & Delay Peak Brilliance & Pulse Duration t •Pulse duration < C< several ns •Large Q’s accessible Development of Split and Delay technology is crucial to success in Ultrafast dynamics with XFEL’s X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 9 9 Aymeric Robert aymeric@slac.stanford.edu XPCS capabilities on XFEL’s LCLS Ultra Fast Mode Sequential Mode LCLS Beam Parameters Full Transverse Coherence 8 and 24 keV X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 High Time–average Brilliance Rep. Rate 120 Hz 10 10 High Peak Brilliance Short pulse duration 200fs Aymeric Robert aymeric@slac.stanford.edu X-ray Correlation Spectroscopy Science Ultra dilute systems ( gases , aerosol, fogs, fumes) Ionic liquids and Transport theories Nano-systems (nanoscale = sub ns dynamics) Biological samples dynamics (in their native state) Dynamics of hard materials ( phonons, low-E excitations,… ) Hard condensed matter phase transitions 1600 -10 °C / 1 bar Q= 1.6 t=5±3 H 2O 2nm-1 t-1 F(Q,t) (a.u.) S(Q,E) (a.u.) 2400 ps 800 0 -10 -5 0 E (meV) 5 0.0 -0.8 1 10 X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 0.8 10 100 t (ps) 11 11 Aymeric Robert aymeric@slac.stanford.edu XCS Instrument Goals/Requirements Goals Time-resolved observation of coherent diffraction patterns using LCLS coherent hard x-rays (6-25keV) Requirements described in SP-391-001-35 Tailor and characterize X-ray beam parameters Spatial Profile Intensity Repetition rate Spectral Bandwidth X-ray Photon Correlation Spectroscopy Requirements Versatility of the instrumentation (SAXS,WAXS, GI) Coherence Preservation of X-ray optics Detector with small pixel size / Large sample-detector distance Key Performance Parameters Provide very large coherent flux on the overall LCLS energy range X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 12 12 Aymeric Robert aymeric@slac.stanford.edu XCS Instrument Location Near Experimental Hall X-ray Transport Tunnel (200m long) XCS Source to Sample distance : ~ 420 m Far Experimental Hall X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 13 13 Aymeric Robert aymeric@slac.stanford.edu Far Experimental Hall X-ray Correlation Spectroscopy X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 Coherent X-ray Imaging 14 14 Material Extreme Conditions Aymeric Robert aymeric@slac.stanford.edu XCS Instrument Overview Photon Shutter Requirement Primary Slits Device Transport Tunnel Diagnostics Tailor X-ray spatial profile X-ray Slits Monochromators Select X-ray energy and tailor spectrum width Control longitudinal coherence length Monochromators Split X-ray pulse and control the delay Split and Delay (MoU DESY) Tailor X-ray spatial profile ( < 50 microns ) X-ray Focusing Lenses Tailor X-ray intensity and spectrum Attenuators Tailor X-ray repetition rate Pulse Picker Tailor X-ray spectrum Harmonic Rejection Mirrors Characterize X-ray pulse intensity Intensity Monitor Characterize X-ray spatial profile Profile Monitor Characterize incident X-ray intensity before optical component of before sample Non-destructive Intensity Monitor Sample orientation and alignment Diffractometer Position X-ray area detector and minimize air absorption and air scattering Large Angle Detector Stage Measure X-ray speckle patterns 2D Detector (BNL) Secondary Slits Diagnostics Split and Delay Secondary Slits Diagnostics Focusing Lenses Photon Shutter Attenuators Pulse Picker FEH Hutch 4 Harm. Rej. Mirrors Defining Slits Diagnostics Diffractometer Large Angle Detector Stage X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 15 15 Aymeric Robert aymeric@slac.stanford.edu XCS Instrument Overview Hutch 4 Optics, Diffractometer Large Angle detector Mover Split and Delay Area Post-Monochromator Large Offset Monochromator X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 16 16 Aymeric Robert aymeric@slac.stanford.edu XCS Instrument Overview Optical raft (1.4.2) Optics and Diagnostics (1.5) Diffractometer (1.4.4.1) Large Angle Detector Stage (1.4.4.3) X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 17 17 Aymeric Robert aymeric@slac.stanford.edu X-ray Optics and Diagnostics Photon Shutter Primary Slits Diagnostics Monochromator Transport Tunnel Secondary Slits Diagnostics Split and Delay Secondary Slits Diagnostics Focusing Lenses Photon Shutter Attenuators Requirement Pulse Picker Device FEH Hutch 4 Harm. Rej. Mirrors Remove X-ray beam halo X-ray Guard Slits Defining Slits Tailor X-ray intensity Attenuators Diagnostics Tailor X-ray repetition rate Pulse Picker Characterize X-ray pulse intensity Intensity Monitor Characterize X-ray spatial profile Profile Monitor Diffractometer Large Angle Detector Stage X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 18 18 Aymeric Robert aymeric@slac.stanford.edu X-ray Optics and Diagnostics Photon Shutter Primary Slits Diagnostics Monochromator Transport Tunnel Secondary Slits Diagnostics Split and Delay Secondary Slits Diagnostics Focusing Lenses Photon Shutter X-ray Focusing Lens System Attenuators Down to 2 μm beam waist Variable spot size below 40-60 μm when working out of focus Can withstand full LCLS flux 3 different configurations Pulse Picker FEH Hutch 4 Harm. Rej. Mirrors Defining Slits Diagnostics Diffractometer Large Angle Detector Stage B. Lengeler et al., J. Synchrotron Rad., 6, 1153-1167 (1999). X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 19 19 Aymeric Robert aymeric@slac.stanford.edu X-ray Optics and Diagnostics Photon Shutter Primary Slits Diagnostics Monochromator Transport Tunnel Secondary Slits Diagnostics Split and Delay Secondary Slits Diagnostics Focusing Lenses Photon Shutter Attenuators Pulse Picker FEH Hutch 4 Harm. Rej. Mirrors Defining Slits Diagnostics Diffractometer Large Angle Detector Stage LUSI Attenuator\Pulse Picker System Excellent Optical Quality > 3 steps per decade of attenuation above 6 keV > 1012 attenuation < 17 keV Isolate 3rd harmonic from fundamental Tailor rep rate up to 10 Hz X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 20 20 Aymeric Robert aymeric@slac.stanford.edu X-ray Optics and Diagnostics Photon Shutter Primary Slits Diagnostics Monochromator Transport Tunnel Secondary Slits Diagnostics Split and Delay Secondary Slits Diagnostics Focusing Lenses Photon Shutter Attenuators Pulse Picker FEH Hutch 4 Harm. Rej. Mirrors Defining Slits Diagnostics Diffractometer Large Offset Monochromator 600mm offset 6-25keV Si(111) and Si(220) Relocation closer to #4, Post-Monochromator DCM 6-25keV Si(111) then Si(511) Scope addition Feb09 Large Angle Detector Stage APS,8ID X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 21 21 Aymeric Robert aymeric@slac.stanford.edu 4-C Hor. Scatt. Diffractometer Photon Shutter Primary Slits Diagnostics Monochromator Transport Tunnel Secondary Slits Diagnostics Split and Delay Secondary Slits Diagnostics Focusing Lenses Photon Shutter Attenuators Pulse Picker FEH Hutch 4 Harm. Rej. Mirrors Defining Slits Diagnostics Diffractometer Large Angle Detector Stage Diffractometer System Horizontal Scattering 4-circle Diffractometer Same platform-CoR distance as XPP Diff Possibility to remove from the beam path (airpads) No interference with CXI beamline (600mm aside) X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 22 22 Aymeric Robert aymeric@slac.stanford.edu Large Angle Detector Mover Photon Shutter Primary Slits Diagnostics Monochromator Transport Tunnel Secondary Slits Diagnostics Split and Delay Secondary Slits Diagnostics Focusing Lenses Photon Shutter Attenuators Pulse Picker FEH Hutch 4 Harm. Rej. Mirrors Defining Slits Diagnostics Diffractometer Large Angle Detector Stage Large Angle Detector Mover Sample/detector distance 7-8m Decoupled from diffractometer SAXS, WAXS, GI 2θ up to 55º, vertical tilt Height adj. X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 23 23 Aymeric Robert aymeric@slac.stanford.edu Large Angle Detector Mover Photon Shutter Primary Slits Diagnostics Monochromator Transport Tunnel Secondary Slits Diagnostics Split and Delay Secondary Slits Diagnostics Focusing Lenses Photon Shutter Attenuators Pulse Picker FEH Hutch 4 Harm. Rej. Mirrors HERIX, sector 30 Defining Slits Diagnostics Diffractometer Large Angle Detector Stage X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 24 24 Aymeric Robert aymeric@slac.stanford.edu XCS Detector 2D Pixel Array Detector Developed at BNL (MoU) 1024 x 1024 pixels 55 x 55 mm2 pixel size High DQE 10 2 dynamic range Noise << 1 photon 120 Hz Readout Rate Delivered in 2012 D/=1.410-4 20mm, Flat Pink : D/=1.5% 20mm, Focussed “Early Science” Detector BNL, 1024x1024 90 x 90 mm2 pixel size 10 4 dynamic range Pink : D/=1.5% 12mm, Focussed X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 25 25 D/=1.410-4 20mm, Focussed Aymeric Robert aymeric@slac.stanford.edu Hutch Facilities XCS Hutch facilities Raised flooring Storage cabinets, work benches and tool chests Extended utilities distribution (water, compressed air,…) Example of the XPP layout X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 Example of the XPP hutch 26 26 Aymeric Robert aymeric@slac.stanford.edu Split and delay The Split and Delay unit will be provided by DESY (Coherence group of G. Grübel) DESY/SLAC MoU in place describing the details of the agreement for the split and delay X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 27 27 Aymeric Robert aymeric@slac.stanford.edu Operating Modes Photon operating modes described in LCLS Document 1.6.009 XCS operation requires SH1, SH2 and S5 open XCS has 2 operation modes: Operation in the LCLS main line (temporarily for early science) Operation in the XCS line downstream the large offset monochromator X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 28 28 Aymeric Robert aymeric@slac.stanford.edu Work Breakdown Structure WBS Scope/CD-2 Cost Includes: 1.4.1 XCS Physics support & engineering integration 1.4.2 XCS X-ray optics & support tables 1.4.3 2D XCS Detector from BNL by MoU 1.4.4 XCS Sample Environment & Diffractometer system 1.4.5 XCS Hutch facilities 1.4.6 XCS Vacuum system 1.4.7 XCS Installation Other related WBS 1.5 Diagnostics & Common Optics, incl. Monochromator 1.6 Controls and data system In kind contribution Split and Delay setup ( from SLAC/DESY MoU in process) X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 29 29 Aymeric Robert aymeric@slac.stanford.edu Scope Early Science Scope (available 2011) Post-Monochromator CD 4 (available in 2012 or before) Large Offset Monochromator Large Angle Detector Mover Diffractometer X-ray Diagnostics (All) X-ray Optics and Diagnostics Support Stands Vacuum System Controls & Data Systems Hutch Facilities “Early Science” Detector X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 XCS X-ray Detector System 30 30 Aymeric Robert aymeric@slac.stanford.edu Transport Tunnel X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 30m 31 31 Beam Dump Wide Angle Detector Stage Diffractometer LUSI Position Monitor LUSI Slits System LUSI Slits System LUSI Attenuators LUSI Pulse Picker LUSI Position Monitor PPS Photon Shutter Valve LUSI Slits System LUSI Position Monitor Photon Stopper Valve LUSI Slits System Split and Delay Unit LUSI Position Monitor Photon Stopper Valve LUSI Monochromators LUSI Slits System LUSI Intensity Monitor LUSI Profile Monitor PPS Photon Shutter Valve LUSI Slit System Complete XCS Layout CXI FEH Hutch 4 Aymeric Robert aymeric@slac.stanford.edu Preliminary Instrument Design Review Design Review held on July 2008 PIDR Committee Members Ercan Alp, APS Bran Brajuskovic, APS Tom Rabedeau, SSRL Quotes from the Report “ We were very positively impressed with the technical, budgetary, and scheduling details given at the meeting. It is clear that what was presented is commensurate with the time frame and financial aspects of such a large project. We commend the technical staff and LUSI management for the work they have done so far. “ PS : Advanced procurement Review for the Diffractometer, the Large Angle Detector Mover and the Large Offset Monochromator 100% completed and DoE Approved on June 16. X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 32 32 Aymeric Robert aymeric@slac.stanford.edu Preliminary Instrument Design Review About the monochromator PIDR Comments In addition to XCS, the scientific scope has been widened to include small-angle x-ray scattering, SAXS, and wide-angle x-ray scattering, WAXS, over 8-24 keV. This expansion may be difficult to realize with tight budget allocation. It may be advisable to split the low energy part and simplify the high-energy effort. Particularly, the large energy range between 8-24 keV is a major cost-determining factor. The science team is advised to revisit this issue. The committee was surprised to see the length and the number of optical components needed to bring the beam into the experimental area. Because of the complexity of the LCSL machine, and the need for diagnostics over 450 m length of the beamline, the choice of 60 cm horizontal off-set between XCS and CXI beamlines might drive the cost up. This should be re-visited after the exact locations of the XCS upstream components are determined. In particular, the location of the monochromator at 200 m upstream of the sample position may prove to be too long of a level arm, in addition to creating a need for a separate beam pipe and additional diagnostics. The need for the horizontal deflecting monochromator to operate between 8-24 continuously should be revisited. A tunable monochromator operating in the larger energy half of this energy range significantly complicates the design of the large offset monochromator, raises the cost of the monochromator, and potentially compromises its stability yet it is not well justified. Instead a fixed energy monochromator operating at some appropriate energy inside this upper energy range should be considered in addition to a tunable large offset monochromator operating in the smaller energy half of the energy range. This approach is more consistent with likely beam split and delay systems that will eventually replace the 8.3keV fixed energy system. The monochromator is supposed to be a common element, and to be duplicated for the XPS beamline, following a contingency plan. Thus any change in scope or implementation is to be coordinated. It may be better to decouple the two instruments, and if in the end, they turn out to be the same, two instruments can be ordered at once. Post Review Resolution The Small and Wide Angle X-ray Scattering sections were always in the scope of the XCS instrument over the full range of the hard X-ray beam produced by LCLS (i.e 8-25keV). For now the SAXS section is however no longer in the scope of the XCS Instrument. The scientific capabilities of the XCS Instrument were refined with the XCS Team Leaders. The high energy range is of importance for the science to be produced for the XCS instrument, as it would allow widening the type of sample that could be experimentally investigated on the XCS instrument, as a result of smaller issues regarding beam damage for higher energies. This will be re-emphasize during the next XCS Team Leader meeting to be held on Oct 19. This issues will be discussed with the XCS Team Leaders on Oct 19. A new approach taking in consideration this recommendation will be presented by the XCS-IIT. The scheme to be presented to the XCS Team Leaders at the next XCS Team Leaders Meeting includes a change in the monochromatization process. The XCS-IIT appreciates the recommendation. To the extent possible both monochromator systems will be identical for the XCS and XPP instrument. In case the requirements differ, the XCS-IIT is ready to design its own monochromator system. X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 33 33 Aymeric Robert aymeric@slac.stanford.edu Preliminary Instrument Design Review About the monochromator Updated Resolution The Large Offset monochromator details were discussed during the XCS Team Leader meeting (Oct 09) The XCS team emphasized its interest in the large energy range of the LCLS spectrum and identified it as an important science driver for the instrument. The monochromator was relocated downstream the X-ray Transport Tunnel, as suggested by the PIDR, but also other reviews. The details of the specifications, cost and schedule and expected performances were reviewed during an independent Advanced Procurement Review on April 23, 2009. The comments from the Advanced Procurement Review were satisfactorily answered by the XCS instrument team. DoE Approval to proceed with the procurement of the Large Offset Monochromator was provided on June 16, 2009. X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 34 34 Aymeric Robert aymeric@slac.stanford.edu Preliminary Instrument Design Review About the Diffractometer/LADM PIDR Comments The long-arm detector mount, LADM, based on the APS-HERIX design, may be overkill in terms of stability and resolution requirements, and therefore a design simplification is recommended for potential cost savings. Specifically, for the XCS application only the detector position need be carefully controlled while the upstream end of the flight arm can be designed with much coarser position control hence cost. The APS HERIX instrument had to line up five elements (sample, slits, detector array, collimator and the analyzer array), thus the requirements were much more stringent. LUSI_XCS team can relax the resolution and the repeatability requirements for the upstream set of stages, and potentially save money. For the LADM, pipe dimension should grow as the x-ray beam progresses towards the detector to minimize the total weight. The granite block to move the diffractometer should be either eliminated or replaced with a cheaper design Post Review Resolution The XCS-IIT agrees. Even if the Large Angle Detector Mover is based on the design of the HERIX spectrometer of the Inelastic Scattering beamline of the Advanced Photon Source, its specifications are relaxed as compared to it. The XCS-IIT will consider this recommendation in the design to the extent possible. For a certain degree of modularity of the sample-detector distance, it might be convenient and cost-effective to combine both approaches. More engineering design is required to evaluate that concept. The XCS-IIT will also investigate different options and proceed to a detailed value engineering investigation of each option. Updated Resolution The details of the specifications, cost and schedule and expected performances were reviewed during an independent Advanced Procurement Review on April 23, 2009. The comments from the Advanced Procurement Review were satisfactorily answered by the XCS instrument team. DoE Approval to proceed with the procurement of the Large Angle Detector Mover and the diffractometer was provided on June 16, 2009. X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 35 35 Aymeric Robert aymeric@slac.stanford.edu Preliminary Instrument Design Review About the Split and Delay PIDR Comments One of the innovative aspects of the scientific program is to extend the time-resolved studies to nanosecond regime by implementing a “split-and-delay” instrument. While this is an exciting prospect, and some early work in Europe proves the feasibility for a fixed-wavelength, it remains to be seen if such an instrument can be developed fully tunable over a large energy range. The committee feels that, if this is part of the scientific program, the “split-anddelay” instrument itself should be included in scope, cost and schedule. The scientific opportunity to implement “split-and-delay” instrument is considered to be very important by our committee, and therefore, every effort should be made to include the construction of this critical component in the main program. However, it is also possible to consider a fixed-wavelength version of the instrument as Phase I, and delay the tunable “split-and-delay” instrument to a later period, after the beamline is completed, and early science experiments are done. Post Review Resolution The XCS-IIT agrees with the review committee and expressed the request to LUSI management. The current plan for the XCS instrument is to get a first prototype of Split and Delay Unit which perform at fixed energy. This prototype is provided by DESY via a SLAC/DESY MoU. The MoU also states that SLAC and DESY should collaborate regarding the development of the next generation of Split and Delay unit (i.e tunable wavelength). The details of this collaborations are not know yet in terms of its SLAC, LCLS, LUSI contribution. the XCS-IIT will make every effort possible to develop this technology at the laboratory. Updated Resolution SLAC and DESY signed an Memorandum of Understanding describing the details of the Split and Delay (provided by DESY ) to be installed and used at the XCS Instrument. The device is already commissioned. The MoU also describes that DESY and SLAC will collaborate in the development of the next generation of split and delay ; i.e an energy tunable in vacuum split and delay. X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 36 36 Aymeric Robert aymeric@slac.stanford.edu Preliminary Instrument Design Review Other Topics PIDR Comments There is a concern that the LCLS electron-beam based source fluctuations may limit the scientific program for XCS. Post Review Resolution These issues are understood and were investigated by the XCSIIT. This justifies the presence of the whole suite of diagnostics and apertures along the beam path, in order to transform any LCLS beam fluctuation into intensity fluctuations. By measuring these fluctuations, with the appropriate diagnostics, one can then normalize the experimentally measured data. Updated Resolution The LCLS is now commissioned and the expected beam fluctuations appear better than expected. The same scheme, as the one previously described will be used. PIDR Comments Photon shutters after each diagnostic element is not necessary, and should be replaced with simple commercial actuators with a steel block at the end. Post Review Resolution The XCS-IIT agrees. The recommended changes will be applied as soon as possible in the design of the XCS instrument. Updated Resolution This has been implemented in the design. X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 37 37 Aymeric Robert aymeric@slac.stanford.edu Preliminary Instrument Design Review Other Topics PIDR Comments Position sensitive detectors with 4-PIN diodes may not have the sensitivity at low photon flux. So the diagnostics detectors should be re-considered. APD based system may prove to be a better alternative. Post Review Resolution This recommendation will be communicated to the Diagnostics and Common Optics Integrated Team in charge of the design of the diagnostics. The XCS-IIT supports strongly this recommendation. Updated Resolution PIDR Comments There seems to too many “coherence-reducing” optical elements in the way before the x-ray beam hits the sample. We have counted some 20-bounces or filter transmissions. While the reduction in coherence at each element may be tolerable, when there are so many, the net coherence degradation should be a concern. The team is advised to look at this issue, and reduce the number of elements in the beam to a minimum. Post Review Resolution The total number of optical elements which may interact with the beam is effectively large, but is required for alignment and commissioning purpose. In running mode of the XCS instrument (i.e while measuring experimental data) the number of such elements is much less (2 bounces monochromator, 2 mirrors and 2 transmission diagnostics only). These are in any case required to conduct the experiment. The optical quality, especially its coherent preservation character is considered in the design of each of these elements, as required to conduct experiment with coherent x-ray beams. Updated Resolution The optical quality of the elements required to be in the beam for running the experiment is monitored. For example, this was tested for the split and delay unit (8 crystal bounces) and was measured to make negligible degradation of the contrast of hard x-ray speckle patterns. X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 38 38 Aymeric Robert aymeric@slac.stanford.edu Preliminary Instrument Design Review Others Topics PIDR Comments It was difficult to get a clean break down between instrument and effort costs, since some of the XCS instruments are common with the other two LUSI beamlines. We advise to remove this uncertainty soon to keep the schedule and cost tractable. Post Review Resolution The XCS-IIT agrees and will discuss this issue with LUSI management Updated Resolution The structure of the XCS instrument components within the LUSI project remained the same, except for the large offset monochromator which is located in the WBS 1.5, but is managed by the XCS Instrument Integrated Team. X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 39 39 Aymeric Robert aymeric@slac.stanford.edu Summary Instrument accommodates a wide variety of cutting edge research capabilities and fulfills the CD-0 mission The XCS instrument is versatile: X-ray optics can tailor FEL parameters for users experimental needs SAXS, WAXS, GI,… User operation start planned for 2011 First call for proposals Spring 2010 XCS Website: http://lcls.slac.stanford.edu/xcs/ XCS 2nd Scientist Opened Visiting Scientist from DESY (Feb 09) Soo-heyong Lee X-ray Correlation Spectroscopy Final Instrument Design Review, June 17-18 2009 40 40 Aymeric Robert aymeric@slac.stanford.edu
