Click OK It may take a minute or two for the Datum to complete. You will know it is done by the message in the lower left portion of the screen, which will read “Datum completed.” Turn on the detector Go to the PHA tab in the Rigaku D/Max-b control window. Make sure that the values for “Base Line”, “Window”, and “Detector HV” correspond to those posted on the monitor of the data collection computer. Click SET for all three PHA properties: Base Line, Window, and Detector HV. Close the Rigaku D/Max-b control window after you have initialized the diffractometer. Set Up the Scan Parameters Part A of these instructions (pg 10- 11) tells you how to create a new data collection program by creating a single new Scan Job in the Task List. Part B of these instructions (pg 12) gives you instructions for collecting data from additional samples by editing a previous Task List. Appendix B (pg 18-22) provides additional information about saving, editing, and using the Task List and Scan Job, as well as information about scan parameters and data collection strategies. A) Creating a New Data Collection Program Go to the menu Scan> Routine Scan … This opens the Setup Scans window that holds the Task List. Never use the Quick Scan option; it doesn’t work well for our instrument. If the Task List in the Setup Scans window already contains a Scan Job, delete it. If you want to use the existing Scan Job (for example, if running a second sample) go to part B (pg 12) for instructions. Set the field “Output Dir:” to the folder where you want your data to be saved. Browse to change the folder where your data will be saved. Set the field “Append data filename with” to None Click on the New Scan Job button. This will open the New Scan Job window, where you can edit scan items. Edit the New Scan Job window Set the filename in the “Filename” field You can provide a sample description in the “Scan ID” field. Click on the New Range button.
The New Scan Range window will open. Define the Scan Parameters in the New Scan window. The New Scan Range window for a continuous scan (on left) and step scan (on right) Start: The minimum start angle is 3° 2theta End: The maximum end angle is 130° 2theta Step: the recommended step size is 0.02° The step size can be 0.01 to 0.05deg You MUST make sure that the scan range is evenly divisible by the step size: for example, if a step size of 0.03, then a scan range from 20 to 40 degrees 2theta (20 deg scan range) would produce an error, while a scan range from 20 to 50 degrees 2theta (30 deg scan range) would be ok. Mode: Continuous is recommended unless you want a scan rate less than 0.2 deg/min Scan Speed is defined differently for continuous and step scan modes For continuous mode, a Rate between 0.2 to 3 deg/min is recommended For step scan mode, a Dwell time between 5 and 10 sec is recommended Axis: should be Both axis should be 0.0, unless the sample includes a single crystal substrate Psi of 1.0 is recommended if the sample includes a single crystal substrate. Appendix B defines the various parameters and offers suggestions for data collection. Click OK in New Scan Range window and click OK in the New Scan Job window, so that you return to the Setup Scans window. the Scan Click on the Start button (in the bottom of the Setup Scans window) to begin data collection. OK on the resulting dialogue The shutter will automatically open and the instrument will to collect data You do not need to remain in the X-ray lab while your data are being collected, but you do need to return to the X-ray lab punctually when your measurement is finished so that you can turn off the instrument and clean up your sample.