calibration

[Theanne Schiros]

Hi there,

When I click to calibrate my data (using 'get from header' as starting
point for the fit), i receive the error message that it is unable to
perform the fit because the program needs at least 8 peaks to do the
calibration. Is there a way around this?

i attached a mar file for C60 as an example of a file i am having
trouble with. Unfortunately this is the case for all my data...

Thanks for any help you might offer.

Theanne
-------------------------------
Theanne Schiros, PhD
Columbia University
Nanoscience and Engineering Center
530 W. 120th St.
Schapiro 901
NY, NY 10027

212.854.6558
ts2...@columbia.edu
-------------------------------

[Joshua Lande]

Hello Theanne. Basically, the way the fitting algorithm works is that
it first tries to find a list of peaks in the data where the intensity
is at a maximum and then it tries to fit the calibration parameters so
that the lines of constant Q lie near the peaks.

The error is saying that the program is unable to perform the first
step of finding a bunch of peaks, which can be caused by the program
having a poor initial guess at the calibration parameters. It is also
possible that you haven't set the true Q values of the source C60
before calibrating the data because without knowing the real Q values
of the calibration standard the program can't know where in the image
to find the rings it needs to calibrate. Do you have a list of the Q
(or D=2pi/Q or 2theta) values for C60 that I can have a look at? If
not, you may need to create one and the format for doing so is
described in the software manual.

Hope this helps and tell me how it goes,

Josh

>  090428_C60_40nm_Si_7a_phi12_600s_17_42_30.mar2300
> 5000KViewDownload
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