calibcant/procedure.tex: Describe residual and approach-retract

Mom suggested more clarity.

diff --git a/src/calibcant/procedure.tex b/src/calibcant/procedure.tex
index 2493fb89501b995fb83f1fdab008ff720d8864cf..9f922227dd790270559f01406d5eb2b928e2595f 100644 (file)
--- a/src/calibcant/procedure.tex
+++ b/src/calibcant/procedure.tex
@@ -36,9 +36,12 @@ during this approach--retract cycle is analyzed to measure $\sigma_p$
   \begin{center}
     \includegraphics[width=0.8\textwidth]{figures/calibcant/bump.png}
     \caption{Measuring the photodiode sensitivity $\sigma_p$ by
-      bumping the cantilever tip on the substrate surface.  This is
-      the first bump from the 2013-02-07T08-20-46
-      calibration.\label{fig:calibcant:bump}}
+      bumping the cantilever tip on the substrate surface.  The second
+      panel shows the residual (measured data minus modeled data) for
+      the bump.  There are two deflection measurements at each
+      position, one from the approach phase, and one from the
+      retraction phase.  This is the first bump from the
+      2013-02-07T08-20-46 calibration.\label{fig:calibcant:bump}}
   \end{center}
 \end{figure}