i would like to ask you about possible reasons for wrong delta D values for IAEA CH7 while IAEA GISP comes out right after normalization to other water standards (SLAP and VSMOW as well as lab water standards). In a recent run, the CH7 suddenly came out approx. 20 per mil too heavy. This has never been the case before. I think it is caused by incomplete conversion of CH7 to H2 gas, especially because I believe to see that the two lowermost heating coils in the furnace are not glowing brightly like all the others. Since I am operating the HT furnace for technical reasons at 1330°C only, every degree less where the glassy carbon sits is likely to become a problem instantly.
I would like to ask you if you can think of other likely reasons for the wrong delta D values for CH7 compared to the water standards. I just want to assure myself that I am not missing something important or obvious before I start to struggle for a (quite expensive) replacement furnace…
Many thanks in advance for your help!
Dipl.-Geograph Marc Ruppenthal
AG Jun.-Prof. Dr. Y. Oelmann
Institut für Integrierte Naturwissenschaften
Tel.: +49 (0) 261 287 2278
Mobil: +49 (0) 176 96810834
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