A noisy H signal with a (mostly) stable CO2 signal is consistent with what we have observed when a magnet control regulator is in the process of failing.-patrickOn Tue, Jul 23, 2019 at 5:10 PM Wei Huang <[log in to unmask]> wrote:Dear all,Our lab has a trace GC isolink coupled with Thermo Delta V through Conflo IV. Recently, we hav a very noisy D/H ratio trace shown as below.Once it happened, I cleaned the ion source, replaced the filament and the slit, re-tuned the ion source. But, the problem still exists.Also, we have found that the value of the HV step during the peak center at the start of an acquisition changes dramatically throughout the course of a sequence - Peak center value could change from 59307 to 60174, no matter with the old filament or the new filament.However, we havn't seen significant noises for our CO2 scan so far, or maybe very tiny bit which can be ignored.Any suggestions or hints are appreciated! Thank you very much in advance!
Wei Huang, Ph.D.
Stable Isotope Lab Manager
Lamont-Doherty Earth Observatory of Columbia University