X23A2 Beamline Evaluation: Data Quality

The purpose of this test is to assess the quality of data for a sample with a small edge step, but which is still thick enough to be measured in transmission rather than fluorescence. This is the sort of data for which multiple scans are required.

Zinc nitrate

445 mg Zn(NO₃)₂ was dissolved in about 40 ml of deionized water and stirred for 5 minutes. The solution was then brought to 50 ml total volume. An aliquot was dispensed into a 2mm thick plastic frame. The windows of the frame were covered with kapton tape. The solution was protected from the adhesive by a small piece of kapton film. This amount of water is less than 2 absorption lengths of water. My sample came out with an edge step of 0.2, about twice as thick as the sample used at the APS.

As expected, X23A2 is somewhat worse than the APS beamlines and considerably worse than 20BM.

Here is an Athena project file with the Zn solution data from all six beamlines.

Cadmium nitrate

The same test is made on a cadmium solution to test the data quality at high energy. 626 mg Cd(NO₃)₂ was dissolved in about 25 ml of deionized water and stirred for 5 minutes. The solution was then brought to 30 ml total volume. An aliquot was dispensed into a ...