Refs #7149 added WIKI comments

Code/Mantid/Framework/Algorithms/src/ModeratorTzeroLinear.cpp

@@ -1,13 +1,25 @@
 /*WIKI*
 
-This algorithm Corrects the time of flight (TOF) of an indirect geometry instrument by substracting a time offset <math>t_0</math> dependent
-on the initial neutron energy being emitted through the moderator.
+This algorithm Corrects the time of flight (TOF) of an indirect geometry instrument by substracting a time offset <math>t_0</math>
+linearly dependent on the wavelenght of the neutron when emitted through the moderator. This algorithm is suitable to data reduction
+of indirect instruments featuring a neutron flux with a narrow distribution of wavelenghts.
 A heuristic formula for the correction, stored in the instrument definition file, is taken as linear on the initial
 neutron wavelength <math>\lambda_i</math>:
-<math>t_0 = a * \lambda_i + b</math>, [a]=microsec/Angstrom and [b]=microsec
+<math>t_0 = a * \lambda_i + b</math>, [a]=microsec/Angstrom and [b]=microsec.
+Below is the example XML code included in BASIS beamline parameters file.
+
+<pre>
+<!-- Moderator Tzero/LambdaZero Parameters  -->
+<parameter name="Moderator.TimeZero.Gradient">
+    <value val="11.967"/>
+</parameter>
+<parameter name="Moderator.TimeZero.Intercept">
+    <value val="-5.0"/>
+</parameter>
+</pre>
 
 The recorded TOF: <math>TOF = t_0 + t_i + t_f</math>, with
-#<math>t_0</math>: moderator emission time
+#<math>t_0</math>: emission time from the moderator
 #<math>t_i</math>: time from moderator to sample
 #<math>t_f</math>: time from sample to detector
 
@@ -17,11 +29,13 @@ For an indirect geometry instrument, <math>\lambda_i</math> is not known but the
 selected by the analyzers is known. For this geometry:
 #<math>t_f = L_f/v_f</math>, with <math>L_f</math>: distance from sample to detector, <math>v_f</math>: final velocity derived from <math>E_f</math>
 #<math>t_i = L_i/v_i</math>, with <math>L_i</math>: distance from moderator to sample, <math>v_i</math>: initial velocity unknown
-#<math>t_0 = a'/v_i+b'</math>, with a' and b'  constants derived from the aforementioned heuristic formula <math>a' = a \cdot 3.956 \cdot 10^{-3}</math> with [a']=meter, and <math>b' = b</math> with [b']=microsec
+#<math>t_0 = a'/v_i+b'</math>, with a' and b'  constants derived from the aforementioned heuristic formula <math>a' = a \cdot 3.956 \cdot 10^{-3}</math> with [a']=meter,
+and <math>b' = b</math> with [b']=microsec
 
 Putting all together:  <math>TOF' = \frac{L_i}{L_i+a'} \cdot (TOF-t_f-b') + t_f</math>, with [TOF']=microsec
 
-If the detector is a monitor, then we can treat it as both sample and detector. Thus, we use the previous formula inserting the time from sample to detector <math>t_f = 0</math> and with the initial fligh path <math>L_i</math> as the distance from source to monitor.
+If the detector is a monitor, then we can treat it as both sample and detector. Thus, we use the previous formula inserting the time from sample
+to detector <math>t_f = 0</math> and with the initial fligh path <math>L_i</math> as the distance from source to monitor.
 
 *WIKI*/
 
@@ -47,8 +61,8 @@ DECLARE_ALGORITHM(ModeratorTzeroLinear)
 /// Sets documentation strings for this algorithm
 void ModeratorTzeroLinear::initDocs()
 {
-  setWikiSummary("For an indirect geometry instrument, subtracts to the time of flight a quantity dependent on the initial neutron energy.");
-  setOptionalMessage(" Corrects the time of flight of an indirect geometry instrument by a time offset that is dependent on the velocity of the neutron after passing through the moderator.");
+  setWikiSummary("Corrects the time of flight of an indirect geometry instrument by a time offset that is linearly dependent on the wavelength of the neutron after passing through the moderator.");
+  setOptionalMessage(" Corrects the time of flight of an indirect geometry instrument by a time offset that is linearly dependent on the wavelength of the neutron after passing through the moderator.");
 }
 
 using namespace Mantid::Kernel;