Import U-Pb data files

PatrickHu

Hi all,

I have an issue with loading U-Pb data files to iolite 4. The file we got out of our mass-spec (Nu Plasma II) was not imported properly. The channels were identified as m238, m235, m219, etc. instead of U238, U235, Pb204 and so.

Do I need to alter the import model in this case?

Thank you in advance!
Cheers,
Pan Hu (Patrick)

Bence

PatrickHu Hi Patrick,
No, there is not an issue with your mass spec. Nu Plasma files only identify the mass, not the element, hence the name of the channels. You should still be able to run the U-Pb DRS though.

Cheers,
Bence

PatrickHu

Bence Thanks Bence,
Appreciate your reply!
I've received the following error message: 'DataManager::timeSeriesByMass] found no matches channels with for 206 of type 2' when trying to crunch my data with the U-Pb Geochronology DRS.
I've noticed that my channels for m238, m235, and m232 were marked correctly. While the 208Pb, 207Pb, 206Pb, 204Pb and 202Pb channels were marked as m219, m218, m217, m215, m213, respectively. Could this be the cause of the problem?

Pan

Bence

PatrickHu While the 208Pb, 207Pb, 206Pb, 204Pb and 202Pb channels were marked as m219, m218, m217, m215, m213, respectively. Could this be the cause of the problem?

Yes, this will cause problems. Taking 206Pb as an example, iolite will look for a channel with a m/z value of 206±0.2. If the data in your mass spec file says this channel has an m/z of 217, iolite will say it cannot find the correct channel.

Is there some way to correct how these masses are reported in the data file? You might want to contact Nu if the solution is not obvious.

Best regards,
Bence

Lindner

Dear All,

I have a similar problem as the one mentioned above.

I also have data from a Nu Plasma II, and I had to change the input Files in order to get to load the data correctly.
I can calculate ages and ratios, however I won't get U (ppm) values and U/Th ratios for my data.

When running the PlasmAge.py script, the columns for f206c, 206Pb, Uppm, Th/U, and 206Pb/204Pb only show "#NV"

Bence

Hi @Lindner ,

I think the issue is if there is no Pb204 measured, you won't get f206c or 206Pb/204Pb. Similarly, if your primary reference material doesn't have ppm values for U, you won't get Uppm or Th/U. Not sure why 206Pb is not exporting... do you see it in your list of intermediate channels (i.e. Pb206_CPS)?

Cheers,
Bence

Lindner

Dear @Bence ,

I have attached a screenshot from my channels (input, intermediate, output)
https://imgur.com/a/I44gjRf
I think I do have the Pb206_CPS intermediate channel (which is the m206_Pb_CPS, i suppose?)

My primary reference Material is the Z_GJ1 standard, which has ppm values for U and Th.

Bence

Hi @Lindner ,

It's not clear why it's not exporting those columns. Would you mind sending an email to the iolite support address, with an example experiment file?

We'll take a look at it and get back to you.

Cheers,
Bence

Lindner

Dear Bence and Joe ,

I have sent an example file to the support email address.

Joe

I believe the plasma age export script specifically looks for Pb206 in a few places and won't be happy with m206. It will need to be updated to select the 206 channel by mass rather than name to support such instruments.

Joe

Hi @Lindner,

I have updated the PlasmAge export script so that it searches for 204, 206 and 208 Pb by mass rather than by a specific name.

However, I have identified an additional problem for the data file you shared with the support email. In this file, your collectors are named according to the element, but the importer is expecting them in a different format. It is a relatively trivial change in the code to allow your collector names through, but I am hoping @Bence knows whether making that change will mess anything else up as someone that has more experience with Nu data.

In the current state, U - 238 is skipped because it expects at least 2 characters for the collector name (things like Ax, H1, L2, ... I suppose). You could open your data file in a plain text editor and add a character after the U, but if you have a lot of files that is a bit tedious. @Bence and I will discuss, make an adjustment to the importer, and get a new version out with the fix asap.

All the best,

Lindner

Dear Joe , thank you! I will try to add the Character after the "U".