Dear Stephen, I apologise for calling you chuisy last time round.
One suggest to test the size of the footprint is, I think, to use common rock salt. Grind this up and place liberally over your plate and you can check at low angle where the X-rays are striking the plate, because the salt will go dark? This should give an idea of how the incident beam changes with slits. Don't quote me on this as I haven't tried it. A nickel filter will remove most CuKbeta. I don't know what source you are using, but is there any risk of fluorescence, because if you are having problems with the slits, regardless of any precautions you take to remove fluorescence, if the slits are not correctly configured then a raised background may be noticed at low angle anyhow. Regards William Bisson On Fri, 4 Jun 2004 [EMAIL PROTECTED] wrote: > Dear William, > > Thank you for your kind suggestion. > > Well, our XRD is not a very new model, we use a fixed divergent slit, receving > slit and antiscattering slits. But I need to check them whether the divergent > and anti-scattering slits are in the same sizes. When I added the anti-scatter > slit, the bump did reduce in size but still there. In this case, can you teach > me what precautions we need to concern when the Ni-filter, beam mask, sample > holder (glass plate) and the receiving slits are used? > > I will make some reading as well, however I do willing to hear some practical > experience from XRD users. > > many thanks, > > stephen chui > > > Quoting William Bisson <[EMAIL PROTECTED]>: > > > Dear Chuisy, > > > > The broad bump you are experiencing at low angle may be to do with the > > slits. One has to be careful with these new XRD machines which have > > variable slits, to make sure the divergent and the anti-scattering slits > > are equal and if you choose to keep the slits fixed, which usually results > > in a broad peak, the footprint is small. However, this will result in poor > > high angle data. > > > > It does require a deal of playing around with the slits to see what each > > of the effects are. The main purpose of variable slits is to have > > consistant data throughout a range of 2Theta, which it will do, however, > > it does make refinement just that little harder, having to take into > > account changing slit width over 2Theta. If anyone has any good tips on > > this matter, I would be very interested to know. > > > > Regards > > William Bisson > > > > On Thu, 3 Jun 2004 [EMAIL PROTECTED] wrote: > > > > > Dear all, > > > > > > We are recently installing a XRD, and there is a huge peak occurred in the > > > 3-7deg (2T) which is masking the useful signals from the sample. How can > > we > > > eliminate the big peak there? > > > > > > We use 40kW, 30mA CuKa x-ray, divergent and receving slits are used, > > > > > > many thanks, > > > > > > stephen Chui > > > > > > > > > > > > > > > >
