We are having some trouble with our dual inlet delta plus, and thought someone
might have some suggestions as to what the problem may be. Here's what has
happened. The instrument had been running fine with no problems for several
months (it has been running deuterium on water via a Finnigan H/device), then the source filament went out. So we took out the source, replaced the filament and put it back in. Pumped down the source overnight, then turned on the HV in the morning. Emission came on and filament blew out within minutes. So now same thing...replaced the filament, pumped down overnight, and flipped on the HV. We had emission (light was on) but we had zero intensity when we would open gas to the source. We have tried it with H and CO2 gas and neither gave us any voltage. We also tried it from both the reference and sample sides and were confident that gas was getting to the source. It's almost as if no ions were being created. When we came in the next morning we found that the new filament had also blown out. We lost two filaments in as many days. Both were Finnigan filaments (which we've always used) bought at the same time. Any ideas as to what the problem could be? Is it possible !
that there is a bad batch of filaments? Or possibly some problem with an electrical board? Any help would be greatly appreciated as we are at a complete loss. Thanks so much!
University of Washington
Stable Isotope Lab
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