Simulation Project powder: Emulating real experimental data

All McStas simulations is performed in units of counts per unit time. Hence, to reach "real" count numbers, one should multiply the simulated intensity, \(I\), by the virtual measuring time, \(t\). There is, however, an upper limit to this value. If the Monte Carlo errorbar scaled with virtual counting time: \(t \delta I\) exceeds the equivalent experimental counting statistics: \(\sqrt{t I}\), the accuracy of the simulation is not sufficient to allow scaling to the given time value. The criterion reads

$t\delta I\leq {\sqrt {t}}I,$

or

$t\leq \left({\dfrac {I}{\delta I}}\right)^{2}$

for every data point.

The McStas tool mcrealistic performs the transformation from intensities to counts under the observation of this rule. Further, it adds "real" counting statistics if some simulation points are "too accurate". This tool will be explained in the class.

Run mcrealistic on your simulated data in the way described in the note "Recipe for Crystallographica-McStas-FullProf interplay". Assume the maximum experimental time allowed by the statistics.

Display the results as a function of \(q\) with errrobars.