Modifying Mail-In Sample Bases

The standard 11-BM mail-in mounting base accepts a Kapton tube of diameter ~ 0.8 mm. The mounted base and matching Kapton tubes are supplied to users with accepted proposals.

For weak scattering samples (low-Z, such as a typical pharmaceutical powder), users may obtain superior signal-to-noise in their data by using a larger diameter Kapton tube. The larger dimeter results in more diffracting sample material, and thus more counts. Make sure that the larger diameter tube will not result in high x-ray absorption.

For these samples, you may also wish to consider modifying the sample mounting base to obtain higher quality data. The standard 11-BM mounting base has a opening which fits the supplied 0.8 mm diameter Kapton capillary. However, this size is not ideal for a low Z composition like Na3FePO4CO3. Some users have carefully enlarged the capillary opening in their issued mounting bases to accept a larger diameter Kapton tube. Note you must purchase these larger diameter tubes.

Making the larger hole is a quick machine shop job to drill out the bases' opening to a larger diameter. The key is to make sure the opening is straight (perpendicular) to the bottom of the base, and centered in the mounting base. The maximum Kapton diameter size (due to the slits on the beamline) is ~ 1.8 mm. The hardest trick can be to securely hold the small sized mounting base in a drill press or mill while machining on the lathe. (easier that with a drill press)

Then you also need to purchase the larger diameter Kapton tubes and cut to an maximum length of ~ 1" (2.5 cm). The new tubes still need to fit inside when the magnetic cap is placed on the base. Also, same as with the standard tubes, the powder and/or any other capillary must be contained and secured inside the Kapton tube.

I recommend one size combination which works well: a 1/16 inch (0.0625 inch) drill to make the hole larger. Then use a Cole Parmer brand Kapton tubing (part number # 95820-12) with an outer diameter of 0.0615" (1.56 mm) and inner diameter of 0.0575" (1.46 mm). In our experience, it will fit very nicely into the new larger 1/16" opening.

see: https://wiki-ext.aps.anl.gov/ug11bm/index.php/Supplies_and_Tools#Capillaries:_Kapton

As an enhancement for early 2013 to the mail-in program, we will be offering bases with this larger opening to offer this an option (using the 1/16 " size). Until then - you will need to make the larger opening yourself.

Let me know if you have any questions.

best Matthew