We are trying to get good diffraction peaks on a STOE diffractometer
with a Ge mononchromator and a scintillation detector. We are dealing with
small amounts of material (0.2 mm filled capillaries or gum tragacanthe
rods). We have done the best we can with diffractometer alignment and
detector tuning and would still like to get more intensity. We have a fine
focus 1500kW tube(Cu).
I have calculated the absorption for copper radiation in air and I
was suprised to find that over the 50cm beam path from source through the
monochromator to the sample and then to the detector the Xrays are
attenuated by about 50%. Helium would only absorb 1% over the same distance.
If I were to put the diffractometer into a dry bag and keep it inflated with
helium, would I see double the counts for my peaks? (and a significant
reduction in low angle background, as a bonus)
Is there a flaw in this logic? If not why don't more people do this,
besides the hassle of changing samples?
Ron
PS. Would the diffractometer float around the room during data collection??
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* Ron Peterson *
* Department of Geological Sciences *
* Queen's University *
* Kingston, ON K7L 3N6 *
* Canada *
* Fax: 613-545-6592 *
* Tele: 613-545-6180 *
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