Hello,
I’m hoping to see if somebody else has been trying to model Johnson noise in MC-ICP-MS, and if so, whether they could provide some insight. It comes down to a simple case of not being able to calculate an intercept correctly (defined below from Paris et al., 2013 Chem Geol; see attached):
Here, the Johnson noise takes the form of a simple y = mx + b, where I am able to reproduce the slope (m = -1), and the remainder of the equation should be the intercept (4.5). If we use R = 0.0442 (34S/32S), and we assume that the noise on both cups is the same (17 uV), we end up with an intercept that's at least an order of magnitude too small (3.4; even if we up the noise to 40 uV; see attached spreadsheet).I’m using the conversion factor 6.25e7 cps/V to convert the voltage directly to cps.
I'm hoping there is something very obvious that I'm overlooking that will hopefully not consume too much time from someone a bit more experienced...
Do you have the paper or the book about the this equation. what is Fig 4.??
Hi Hongseok,
I have resolved this question recently, but thank you for your interest!
The equations are from Paris et al., 2012 (Chem Geol).
Cheers,
Jakub
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