monitor normalisation and error bars

[rsibille-psi]

The error bars are not properly normalised in pyzebra it seems. For instance, I open dat file 6349 of experiment 20211272, the natural monitor is 6 millions. The plot produced by pyzebra is normalised to monitor 100000 with unrealistically large error bars (image 1), while if I impose the natural monitor to pyzebra the error bars look correct (image 2) and consistent with our old "fit" tool (image 3).

[ivan-usov]

Currently, the errors are calculated as sqrt(n), where n is the number of counts. The number of counts scales linearly to a monitor value. What would be the right way to scale errors in that case? I guess, sqrt(original_n) * monitor_scale?

[rsibille-psi]

yes, with monitor_scale the ratio between the original and new monitors. thank you very much.

[ivan-usov]

let me know if it works, then I will update the main server too

[rsibille-psi]

yes it does work properly I think. Thank you!

From: Ivan Usov @.> Reply-To: paulscherrerinstitute/pyzebra @.> Date: Wednesday, 29 September 2021 at 16:54 To: paulscherrerinstitute/pyzebra @.> Cc: "Sibille Romain Franck (PSI)" @.>, Author @.***> Subject: Re: [paulscherrerinstitute/pyzebra] monitor normalisation and error bars (#40)

let me know if it works, then I will update the main server too

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