very low counts in standards

[Alejandro Cortes]

While our Jeol is being repaired I decided to venture in the cameca instrument we also have for the first time. I am experiencing issues with counting on standards. Peak positions are found effectively but retrieving less than 2k cts. While for Si (Spec 4 TAP-Albite) and Na (Spec 2 LTAP-Albite) this is fine, Al is really bad (Spec 4 TAP - Corundum). I though this had to be with column alignment but then why is it good for some elements and bad for others... Any input will be greatly appreciated.
 

[Probeman]

While our Jeol is being repaired I decided to venture in the cameca instrument we also have for the first time. I am experiencing issues with counting on standards. Peak positions are found effectively but retrieving less than 2k cts. While for Si (Spec 4 TAP-Albite) and Na (Spec 2 LTAP-Albite) this is fine, Al is really bad (Spec 4 TAP - Corundum). I though this had to be with column alignment but then why is it good for some elements and bad for others... Any input will be greatly appreciated.

That sounds like spectrometer alignment issues to me.   

Usually this requires a service engineer but if you have instructions it can be done by any competent technician.  For alignment of TAP spectrometers one first vents the instrument, then removes the spectrometer covers and all column separation windows (of the low pressure spectrometers) and replace them with Mylar windows. Then pump the column down again, but leave the covers off the spectrometers so they are at atmosphere. One then utilizes high order reflections (i.e., Fe ka 4th order) to perform the spectrometer alignments.

Be careful to keep your hand out of the x-ray beam coming through the Mylar windows!

[wonachlas]

It sounds like there may be a leak in the detector window. This can cause counts to be present, but abnormally low, on one spectrometer but not others. To check for leak in detector window, remove detector from mounting rod, submerge in beaker of methanol and watch for bubbles. A small leak can produce a bubble every few seconds, which can still sustain some pressure in the detector and cause low, non-zero counts. Replace the window and count rate should return to similar values as the other spectrometers.