p = sw_res(source,poldeg)
p = sw_res(source,poldeg,true)
p = sw_res(fid,poldeg) reads tabulated resolution data from the
source file which contains the FWHM energy resolution values as a
function of energy transfer in two columns. First column is the energy
transfer values (positive is energy loss), while the second is the FWHM
of the Gaussian resolution at the given energy transfer.
p = sw_res(fid,poldeg,plot) the polynomial fit will be shown in a
plot is true.
This example shows how to fit a tabulated resolution data (MERLIN energy resolution for meV and 300 Hz chopper frequency). Using the fitted polynomial, the energy resolution can be calculated at an arbitrary energy transfer value.
resDat = [0 2.31;10 1.80;20 1.37;30 1.02;40 0.78;49 0.67]
resDat = 0 2.3100 10.0000 1.8000 20.0000 1.3700 30.0000 1.0200 40.0000 0.7800 49.0000 0.6700
polyRes = sw_res(resDat,3)
EN = 13 dE = polyval(polyRes,EN)
dE = 1.6635
- String, path to the resolution file or a matrix with two columns, where the first column gives the energy transfer value and second column gives the resolution FWHM.
- Degree of the fitted polynomial, default value is 5.
truethe resolution will be plotted, default value is
- The coefficients for a polynomial of degree that is a best fit (in a least-squares sense) for the resolution data. The coefficients in are in descending powers, and the length of is :
[polyfit] | sw_instrument