How long a multiplier detector lasts depends on the type of multiplier
and the number of ions that enter into the multiplier. You should
determine what type of multiplier you have and then you can find the
normal operating voltage for your multiplier. Five years is a long time
if you use the instrument on a daily or even weekly basis.
In general, as you increase the operating voltage on the multiplier you
will see an increase in the number of counts per second for a given
isotope. You can make a graph of the operating voltage versus counts and
generate a curve for your multiplier. At some point, increasing the
operating voltage will no longer increase the count rate and produce a
flat part of the curve. Increasing the voltage will often, but not
always, result in increasing counts again. If your multiplier produces
such a curve, the ideal operating voltage would be in the middle of the
flat part of the curve where a small change in voltage would produce a
small change in the count rate.
Not all multipliers have the same operating curve so you need to know
what type of multiplier you have. Multipliers are considered a
consumable item in ICP-MS so replacing it after 5 years is to be
expected. If your instrument has a faraday collector you can compare the
count rates of the multiplier to the converted count rate or analog
signal of the faraday. If you need more information do not hesitate to ask.
Department of Terrestrial Magnetism
Carnegie Institution of Washington
5241 Broad Branch Road, NW
Washington, DC 20015
On 9/7/11 9:04 AM, Luca Fedele wrote:
> Dear All,
> We own the Agilent 7500ce with ORS. Machine has been running smoothly since
> 2006, but I have a question ...
> We are thinking to replace the detector, however it is not clear to me if it
> is necessary or not at this point.
> We use this ICPMS only with a laser ablation system.
> Voltages are currently: Analog 2090 and Pulse 1260.
> Any suggestion will be greatly appreciated.
> Luca Fedele PhD
> Department of Geosciences
> 4044 Derring Hall
> Virginia Tech
> Blacksburg, VA, 24061
> VT Fluids Research Lab - http://www.geochem.geos.vt.edu/fluids/laicpms/
> AMS - Software for Laser Ablation Data Reduction (by Scott Mutchler) -