Thursday, April 7, 2011

Selecting integration periods automatically (Part 2)

As promised, this post will cover the 3rd option of automatic integration selection called "detect from beam intensity". This option allows you to select portions of your data that satisfy up to three different criteria (e.g., where U238 is greater than 10000 counts per second). Because such criteria are independent of how your data were collected (e.g., numerous small files vs. a single large file), the method is particularly useful for sessions that don't include some sort of labelling for each analysis. This first short video demonstrates the basics of the interface using a U-Pb dataset as an example:



So you would have noticed the extra level of feedback in this option, with the graph showing not only the location of each integration period, but also which ones you've selected, and the location of any pre-existing integration periods for the selected integration type.

But there's one other thing about this new option which we think makes it really powerful, which is that in addition to your input channels you can also use intermediate and output channels as selection criteria. This means you can use an isotopic ratio, or even the calculated 206/238 age of an analysis to distinguish between analyses, as this next video demonstrates:



The other benefit of being able to use intermediate and output channels is that anyone who's really keen can make waves in their DRS specifically for assisting in selecting integrations. For example, you could make an intermediate wave that is given the value 0 for all parts of your data that you don't want to select, and the value 1 for time intervals of interest, then use this wave as your selection criterion in the "detect from beam intensity" interface. In this way, you could either come up with discriminating criteria that are more complex than what's provided in the current interface, or just make your life a little easier by, for example, rolling three different criteria into a single wave, so that you don't need to set everything up in the interface every time you use it.

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