Refs #16. instruments.sequoia: support violini workflow method

dgsres/instruments.py

@@ -20,13 +20,14 @@ class arcs:
     def scattering_angle_constraints(cls, theta, phi):
         return ((theta<135.) * (theta>-28)) * (phi<26) * (phi>-27)
 
-    
+
 class sequoia:
 
     instrument = sx.instrument(
         name = 'SEQ',
         detsys_radius = "5.5*meter",
         L_m2s = "20.05*meter",
+        L_m2fc = "18*meter",
         offset_sample2beam = "-0.15*meter" # offset from sample to saved beam. don't change this unless you are sure what you are doing
     )
 
@@ -40,6 +41,13 @@ class sequoia:
     def scattering_angle_constraints(cls, theta, phi):
         return ((theta<60.) * (theta>-30)) * (phi<18) * (phi>-18)
 
+    class violini:
+
+        tau_P = 10
+        tau_M = 8
+        sigma_thetai = 0.01
+        sigma_phii = 0.01
+
 
 class cncs: