I have only once experienced the problem of saturating the pulse detector
with low concentration solutions. This happened when using a DIN. I was
aquiring counts of around 20,000 cps at 20ms dwell times. I attributed the
problem down to ineffeciently optimised nebulization as very noisy count
were being aquired. what i did find though was that on changing from pulse
counting mode to dual mode the problem disappeared. I no longer had 'S'
values but still had a noisy signal.
My simple interpretation is this
The analog detector is activated once the pulse mode is saturated (ie;
normal detector response with high count rates). However as less than
2million counts are reported by the analog detector it would appear as
though the signal spike is only affecting the pulse side of the detector.
Quite how this is achieved I am not sure, maybe someone with more detailed
electronic knowledge of how the detectors aquire signal and process this
Obviously this will only work if you have correctly setup the dual detector
calibration file. To cross calibrate both analog and pulse detector modes
on fully optimizing the DIN, the 'detector problem' dissappeared and has yet
dept of geological science
>We have an ELAN 6000 that seems to behave a bit strange sometimes. What
>happens is that when we run a sample an for a given element and have a
>stable signal, suddenly one reading gives "S" which means that the signal
>is higher than can be read in pulse counting mode (>2.000.000 cps). It can
>happen with only one reading in a long line of readings around 50.000 cps.
>This also happens when I look at two different isotopes of the same
>element, with short dwell time, then suddenly for one of the isotopes in
>one reading "S" appears???
>It seems unlikely that it actually should give this high readings (from a
>particle etc.) just in 10 ms on one isotope of an element (It happens with
>many different elements).
>Have any of You Elan 6000 users out there experienced anything like this?
>Can anyone tell me why this happens or if there is anything to do to avoid
>Thanks for Your reply.
>Best regards Erik
> Best regards:
> Erik Buseth
> University of Agriculture
> Laboratory for Analytical Chemistry
> P.O.Box 5026
> 1432 Aas, NORWAY
> Tlf. + 47 64 94 83 44
> FAX. + 47 64 94 83 32
> e-mail: [log in to unmask]