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FCS-analysis / PyCorrFit

data analysis and fitting software for fluorescence correlation spectroscopy (FCS)
pycorrfit.craban.de
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Definition of the structural parameter #195

Closed ESlenders closed 4 years ago

ESlenders commented 4 years ago

According to p. 20 of the manual, the structural parameter is defined as the square of the ratio of the height and the weight of the PSF. However, Eq. 12, a couple of lines below this definition, suggests that SP is just the ratio, not squared. I'd expect the latter to be the correct one. Could you confirm this?

Thanks. Eli

weidemann commented 4 years ago

Correct. Structure Parameter is SP=z0/w0, whereby w0 is the 1/e^2-radius in xy and z0 the 1/e^2-radius along the optical axis z.

1/e^2 radius is the radius in which the Gaussian intensity dirstribution has decayed to 1/e^2 ~ 1/(2.7)^2 ~1/10th

paulmueller commented 4 years ago

Thanks for spotting that. I updated the manual.