Agilent 7700 ICP-MS Electron Multiplier Failed

Hi emreretoprak, 

I have just replaced the electron multiplier myself at ICP-MS 7900. I have reset the EM and done an EM auto setting. I've got discriminator at 3.6 mV, analog 2197 and pulse 950 V. I have done a PA factor adjustment in batch, but on the tune report generated the sensitivity has gone down by half using the same lenses voltages and plasma conditions. Before the change we had 59 and 89 sitting at around 1000cps and 205 at around 2000 cps. Any suggestion? 

Hi, 

assuming all cables are correctly installed, and none is missing, the most common issue is, that the washers from the fixing screws are under the baseplate of the EM. 
They need to be on top of the baseplate, so that the EM is flat on ground. 

Hi, 

assuming all cables are correctly installed, and none is missing, the most common issue is, that the washers from the fixing screws are under the baseplate of the EM. 
They need to be on top of the baseplate, so that the EM is flat on ground. 

Hi cschulz,

Thank you for your help. I opened again  to check and two of the wires were touching some metal on the detector. It seems to be okay now.