Instructions XRD. 1 Choose your setup , Sami Suihkonen. General issues

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1 Instructions XRD , Sami Suihkonen General issues Be very gentle when closing the doors Always use Cu attenuator when count rate exceeds c/s Do not over tighten optical modules or attach them misaligned (module edges should align with module holder edges) Make sure detector side cables cannot knock down other modules when moving Do not move the tube when the generator is on 1 Choose your setup Choose a setup and screw modules in place. X-ray reflectivity (XRR) o Thin amorphous or crystalline film (<200nm) thickness, density and roughness Grazing incidence XRD (GIXRD) o Very thin film XRD (<100 nm). o Assumes random orientation, i.e. not suitable for preferred orientation Powder XRD (PXRD) o XRD of powders and bulk polycrystalline samples. Suitable for preferred orientation High resolution XRD (HRXRD) o Single crystal measurements.

2 1.1 XRR and GIXRD setup Incident beam optics o Progressive divergence slit (PDS) set to fixed 1/32 Soller slit 0.04 rad Mask, 5-20 mm Ni-filter (blocks Kβ- and broadband background radiation) o X-ray mirror (in extended position) ½ divergence slit Cu 0.1 mm attenuator, Attenuation factor , Activate 400k c/s de-activate 200k c/s o Monocromator, none Diffracted beam optics o Anti scatter slit: none o Receiving slit: Parallel plate collimator Slit o Filter: none o Mask: none o Soller slit: 0.04 rad o Beam attenuator: none o Mirror: none o Detector: either [1] or [2] o Collimator: Coll. 0.18" o Monocromator: Diff. Beam Flat Graphite

3 1.2 PXRD setup Incident beam optics o Progressive divergence slit (PDS) set to fixed 1/32 with attachments: Ni-filter (blocks Kβ- and broadband background radiation) Soller slit Beam mask. Size 5, 10, 15 or 20, depending on required beam size Diffracted beam optics o Progressive anti scatter slit (PASS) set to fixed 1/32 with attachments: Cu 0.1 mm attenuator (if not present in incident beam side mirror) Soller slit (optional) Progressive receiving slit (PRS) set to 3 mm Diffracted beam monochromator PW3123 Detector (either [1] or [2])

4 1.3 HRXRD setup Incident beam optics o Divergence slit: none o Mask: none o X-ray mirror Cu (MRD) in extended position ½ divergence slit (not in program options) o Monochromator 4xGe220(Mirror) Manual Crossed slits 4x4mm is a good starting point o Attenuator: Cu 0.1 mm (no need to set in program options during alignment) o Filter: none o Soller slit: none Diffracted beam optics o Triple axis with two beam paths: Anti-scatter slit, Receiving slit, Filter, Mask, Soller slit, Collimator, Mirror, Beam attenuator: none Lower beam path: Monochromator: Triple axis, 3 bounce, Detector [2] Upper beam path: Monocromator: none, Detector [1]

5 2 Starting procedure Close doors Open water flow, first outlet, then inlet Turn machine on from POWER button o Machine will lock doors, turn on generator and initialize o Wait until it is ready (1 min) o Open software Data Collector and connect to the right configuration XRR and GIXRD: Instrument->Connect->Linefocus_Collimator PXRD: Instrument->Connect->Linefocus_PRS+PASS HRXRD: Instrument->Connect->Linefocus_Triple axis, lower beam path o Clear sample offsets "No" Check that the components listed in Incident beam optics and Diffracted beam optics match the fitted modules o Mirror position, extended or standard, must be specified correctly to avoid ~0.8 error in 2θ o Especially for XRR measurements the Cu 0.1 attenuator settings need to be correct: Incident Beam Optics/Beam attenuator/cu 0.1 mm manual Activate at pre-set intensity, new user default values are wrong, correct ones: Activate level c/s De-activate level c/s Attenuation needs to be , new user default value 20 causes problems! can be changed in Main screen/customize/beam Attenuators Tube breeding o Machine has not been used in less than 100 hrs, no breeding is needed o Machine has not been used in more than 100 hrs, choose Tools->Tube breeding->fast (15 min) o Normal tube breeding (40 min) is needed only when conditioning new tube for the first time. Set tube current and voltage in Instrument Settings->X-Ray Generator to 40 ma and 40kV

6 3 Alignment 3.1 Basic alignment Step needs to be done only once after changing modules or starting machine. Steps and need to be done after changing sample Align detector to incident beam Make sure the Cu 0.1 attenuator is in place, and its settings are correct (see 2. Starting procedure) Scan 2θ around 0; the peak intensity must be the true 0-position (beam goes direct into detector) o Measure -> Manual scan->scan axis=2θ o Scan range usually < 0.5 o Time per step=.05 o Choose step size to taste (e.g for XRR, GIXRD and PXRD, for HRXRD) o Set position to 0 Right click and choose Peak Mode to calculate peak position. Press Move To, the detector will move to position of max intensity Save the offset in Tools->Sample offsets o Sample offsets works so that you always type in the value of what the current position SHOULD be and then press OK o In this case, it should be 0

7 3.1.2 Adjust sample height Increase Z-value until ½ of the intensity is blocked by the sample There is no scan for this Change z-value at Positions->z No need to save offset Align sample parallel to the beam The sample will be slightly misaligned, i.e. ω=0 will not correspond to zero angle between sample surface and beam. There are two ways to do the alignment, both scan ω to find the maximum value Direct beam: Scan ω around 0

8 Works for all samples Slightly inaccurate Scan ω around 0; the peak intensity must be the true 0-position (sample parallel to beam) o Manual scan->scan axis= ω o Scan range usually < 3 o Time per step=.05 o Choose step size to taste, e.g o Save ω peak position in offsets as 0 o Adjust z again, if offset is large Totally reflected beam: Scan ω around mirror condition Works for smooth, straight, well reflecting samples Very accurate Scan ω around half of 2θ value, i.e. assume mirror condition. The peak intensity must correspond to the true value of ω= θ. o Manual scan->scan axis= ω o Set position, e.g. 2θ=0.4, ω= 0.2 o Scan range usually < 3 o Time per step=.05 o Choose step size to taste, e.g o Save ω peak position in offsets in this case as 0.2, i.e. half of 2θ value if another 2θ value is used o Adjust z again, if offset is large, but remember to set 2θ=0 and ω=0 The diffractometer and the sample are now aligned.

9 4 XRR measurements 4.1 Test measurement A quick ω-2θ scan to check that everything is ok: o make sure that Cu 0.1 attenuator is in place o Manual scan->scan axis= ω-2θ o Set centre position of the measurement e.g. ω= 0.6 o Scan range usually e.g 1 o Time per step=.05 o Choose step size to taste, e.g , 1 min scan should be sufficient o This will make a ω-2θ scan from 0.1 to 1.1, which should show a total reflection at around ω< 0.3 and several oscillations o You should be asked to remove the Cu 0.1 attenuator when detector counts fall below 2000, and insert the attenuator when the scan is finished 4.2 Full measurement Use measurement programs to measure and automatically save data Create program: File->New program o Absolute scan o Linefocus_collimator, continuous o Choose scan Axis ω-2θ for XRR o Choose step size and time per step according to preference o Close and it will ask you to save changes To measure, choose: Measure->Program->Your program->give the file an unique name 4.3 Data export The data may be inspected using the software X'Pert Graphics&Identify The data can be exported using the software X'Pert Organizer o Choose Database/Export/Scans and select the files you want to export o Select all files in the Export Scans window and choose Folder and select your folder in C:\Program Files\Phillips\X'Pert Software\Data o Check that Xnn file format is selected o Select again all files and choose export o Copy the exported files to shared folder E:SharedWin2kXP\your folder o You can now access the files in WinXP 4.4 Data analysis The exported scans can be analysed with XRR simulation software Software available from the main users Tips: o o The software is installed by unzipping the contents of the xrr.zip file to a folder. Software is started by running the xrr.jar file. The simulated layer structure can be modified in the Layer editor -tab. The default layer structure consists of a silicon substrate, native oxide and the thin film layer. Layer parameters can be modified by selecting the desired layer and clicking the Edit -button. The fit-check box selects the parameters for automatic fitting.

10 o o o The simulated reflection curve of the layer structure is shown in the Manual fit -tab. Measurement data in.x00 format is added to the software from File/Load measurement. Automatic fitting is done in the Automatic fit -tab. First load the layer structure from Import model. Export model returns the fitted values to the Layer editor -tab and manual fitting window. Default fitting parameters of the software can be used. Fitted reflectivity curves can be exported in.txt format after fitting from Data/Linear plot and File/Export. First column of the text file is the angle (θ in degrees), second the simulated data and third the measured data. Fitted layer parameters can be exported in.txt format from File/Export layers to text file.

11 5 XRD measurements 5.1 Align a specific reflection Use Positions->Unit cell->your unit cell to insert Miller indices. The program will calculate angular positions based on unit cell parameters. Press OK If using HRXRD, switch to Upper beampath o Large acceptance angle will help in alignment Use manual scans to maximize intensity and bring the sample to the Bragg condition o rough ω-scan o ~7 φ scan, can in theory be omitted for symmetric reflection o ~7 ψ scan o More accurate ω scan If using HRXRD, switch to Lower beampath o Accurate 2θ scan 5.2 Full measurement Use measurement programs to measure and automatically save data Create program: File->Program->New program o Choose scan Axis o Choose step size and time per step according to preference o Close and it will ask you to save changes To measure, choose: Measure->Program->Your program->give the file an unique name 5.3 Data export The data may be inspected using the software X'Pert Graphics&Identify The data can be exported using the software X'Pert Organizer o Choose Database/Export/Scans and select the files you want to export o Select all files in the Export Scans window and choose Folder and select your folder in C:\Program Files\Phillips\X'Pert Software\Data o Check that Xnn file format is selected o Select again all files and choose Ok o Copy the exported files to shared folder E:SharedWin2kXP\your folder o You can now access the files in WinXP 5.4 Data analysis The exported scans can be analysed with XRD simulation software Software available from the main users

12 6 Shut-down Set generator current and voltage in Instrument Settings->X-Ray Generator to 15 kv and 5 ma Let tube cool down for a few minutes Insert Cu 0.1 attenuator Set diffractometer to zero position and remove the sample Switch off the generator Instrument->Disconnect Turn off the cooling water System stand by 7 Problems Diffractometer will not start, cannot connect to instrument o Doors were not locked and the instrument could not initialize o Turn off XRD-machine, close doors properly and restart No signal o Wrong detector