Negative Rb/Sr results

jmacc

I have been working through using the software and have come across a strange bug/thing happening.
During the reduction of some Rb-Sr data I have had exported a few samples with negative Rb/Sr ratios, the issue is being is that my counts for Sr86, Sr87 and Rb87 are all positive in both inputs and intermediate, but it is when I get to the final output stage that the ratio inverts and turns negative.

The sample I am having the issue with is a muscovite sample so the Sr/Sr would already be low, but there is no reason as to why the output ratio just inverts and turns negative. I am using NIST610 as my reference.
I don't really know what to do, what information can I give you to help me/do you know how to fix this issue?

I have other negative ratios throughout my samples but they are randomly spread out throughout the sample's points and not consistently negative like this sample I have.

Bence

Hi @jmacc

Negative ratios are almost always associated with incorrect baseline splines. To get a negative ratio, one counts value must be negative, and this is where the counts for a sample is less than the baseline spline. I would recommend checking the baseline spline for all channels if you get a negative ratio.

That said, we did fix some bugs in the Neoma Rb/Sr DRS recently, so I would also recommend downloading the latest version from the GitHub repo if you're using the Neoma. There are instructions for downloading from the GitHub repo here: https://notes.iolite.xyz/posts/downloadingfromgithub/

Please let us know if you have any troubles.

Kind regards,
Bence