U concentrations

Troy

Hi Bence and Joe,

In the past my U-Pb geochronology DRS (which I haven't modified) gave U concentrations and errrors but now I only get Pb concentrations. How can I get the U concentration results again?

Troy

Joe

Troy
That depends on why they're missing and where they're missing from. Are the channels created? Are the channels created but blank? Are the channels created and seem ok but not being exported?

Using the built-in U-Pb DRS, the Approx_U_PPM, Approx_Th_PPM and Approx_Pb_PPM channels are created as long as the U, Th and Pb concentrations are found for the reference material data. Having just reviewed the code, I can see that if you're using an instrument that records m238 (or similar) rather than U238, the concentrations will not be calculated -- I've just fixed that now. Which reference material are you using? Are you using an instrument that doesn't record the element?

All the best,

Troy

I am using WC-1, a calcite reference material. I have been using it for a long time and it was working, but maybe the RM file is corrupted. I didn't think of that.

Thanks!

WangJian

Hi Bence and Joe,

The U238 concentration in my sample is high so I only collect the U235(the instrument doesn't record the U238)，but the U238 input is set to 0 automatically, then the output is no information about the U concentration;
I tried to use the Calculator tool to replace the U238 input by U238=U235*137.818, the calculation worked and the channel changed in Time Series.
But when I try to run the U-Pb geochronology DRS, it gives the error message: "A required channel (one or more of 206, 207, 238) is missing."
What I should do to replace the U238 input channel completely? or only use the U235 to get U concentration？

Sincerely,
Jian

Joe

Hi WangJian

You should be able to set "U isotope selection" to 235 only, but I can see now that the DRS will still insist on 238 being there. I'll fix that for the next release.

In the meantime, you were on the right track I think. You should be able to create a U238 channel using the calculator. The trick is that the DRS does not look for "U238" it looks for a channel with its "Mass" property set to ~ 238 so that machines recording as "m238", for example, still work. After you create the channel with the calculator (being sure to create it as an input channel), open up the python console via the Tools menu and enter:

data.timeSeries('U238').setProperty('Mass', 238)

I think that should do it, but please do let us know if not!

All the best,

WangJian

Joe
It works well.
Thank you very much!

Best wishes,
Jian