Yes, with our high temperature stage on a Scinatg diffractometer, we gain
back nearly all the intensity lost by absoprtion to the window by filling
the chamber with He.
He flight paths are the way to go, so I agree, why don't the manufacturers
develop this idea.
>Hello All,
> Can anyone suggest to me if there is something wrong with the
>following reasoning.
>
> 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??
>******************************************
>* Ron Peterson *
>* Department of Geological Sciences *
>* Queen's University *
>* Kingston, ON K7L 3N6 *
>* Canada *
>* Fax: 613-545-6592 *
>* Tele: 613-545-6180 *
>******************************************
Neutron Scattering Section
Solid State Division
Oak Ridge National Laboratory
Oak Ridge, TN 37831-6393
423-574-5235 phone
423-574-6268 FAX