SAXSLAB Operation Checklist Engage the SAXS instrument in Coral Ch I Assess instrument status and safety Is the instrument on? Is the generator on? What is the tube power? Is the shutter open? Ch I Ensure the X-ray tube is at full power 45 kV and 0.66 mA for the Cu microfocus tube Ch I Start the Ganesha System Control software Ch I Start the Ganesha GUI software (Ganesha Interactive Control Center, GICC for short) Ch I Vent SAXS system Ch II Load Ambient 8x8 holder with freestanding or capillary samples Ch II Evacuate SAXS system Ch II Plan SAXS measurements Ch III Align Ambient 8x8 holder to beam Ch III Write and run and automated measurement macro Ch IV Data reduction with SAXSGUI software Ch V When finished Leave the tube power at full power level: 45 kV and 0.66 mA for the Cu microfocus tube Vent SAXS system Retrieve your sample Evacuate SAXS system Clean the sample stage and sample holders Copy your data to a secure location Disengage the SAXS in Coral Ch VII The Chapter number and section number on the right-hand side of the page indicate where you can find more detailed instructions in the SAXS SOP.
t = 1/μ , where μ is the thickness at which the incident intensity is reduced by 1/e. To perform measurements on an absolute scale the thickness of the sample must be known. In Measurement Details, type in the sample thickness in centimeters. Check boxes for “Transmission + I0” and “BS mask” The volume normalized differential scattering cross section is calculated by, , where V is the volume of the sample, I(q) is the scattered intensity, B(q) is the background intensity, I0 is the intensity in the forward scattering direction, T is transmission factor, t is thickness of the sample and (ΔΩ) is the collection solid angle. By collecting data as a function of the differential scattering cross section, one can quantify certain values (number density of scatterers, molecular weight, volume fraction, specific surface area, surface-to-volume ratio, volume weighted or number weighted mean size). Note down Image number and click Measure button. IV. Writing and Running an automated measurement macro This section covers making a macro to automate the data collection at multiple sample positions, detector configurations and, when enabled, will display scattering data on an absolute scale. The y-axis is differential scattering cross section in units of cm-1 and the x-axis is photon momentum transfer, q, in Å-1. Open the right panel for the macro editor with the “>” button. Notice: When clicking on any buttion in the GICC, the action is not performed but instead, written into the macro list. At the top of the macro editor, click the “New” button Move to the sample of interest in position (Z,Y) by clicking on it in the Current Holder panel. Click Sample to Beam button. In Measurement Details, select a measurement Add a description including: sample name, exposure time, hole position, sample thickness Choose a measurement time in seconds. Measure button. Repeat for all samples in holder. Save macros written in the GICC panel with the .gicc extension. If you’d like to insert an instruction in a macro ahead of another without deleting all of the instructions, right click on the instruction and select “Insert before”. The instruction clicked has an anchor icon next to it. Perform mouse clicks on GICC to insert intended action. When done adding actions, right click and “Disable insert before”