.. _sec_qg_consistency_check:


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Checking experimental data for consistency
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- **Trends over time:**

  To verify that the sample "behaves" stationary during the measurement, it is helpful
  to plot a few selected features versus time. No systematic deviations should
  be observable, as in the figure below.

  .. figure:: figures/qg_time.jpg

     Deformation and event area versus time. There is no
     systematic trend over time, indicating stable measurement conditions.


- **Countrate:**

  Trends over time do not directly visualize the count rate (measured events
  per second). The count rate is the slope of the event index versus event
  time plot and should remain constant.
 
  .. figure:: figures/qg_countrate.jpg

     The event index versus event time plot shows a constant slope, an
     indicator for stable measurement conditions.
 