modified: ../../.gitignore

	modified:   part1/simple_detector.md
	modified:   ../../static/gem_tracker_part1.png

.gitignore

@@ -5,6 +5,8 @@ npm-debug.log*
 yarn-debug.log*
 yarn-error.log*
 
+package-lock.json
+
 # Runtime data
 pids
 *.pid

src/docs/part1/simple_detector.md

@@ -50,8 +50,8 @@ Examine the compact description, specifically this part:
   <layer id="1" z="-100 *cm" inner_r="40*cm"  outer_r="120*cm"   phi0_offset="0.0*deg" />
   <layer id="2" z="-80 *cm"  inner_r="30*cm"  outer_r="90*cm"    phi0_offset="0.0*deg" />
   <layer id="3" z="-60 *cm"  inner_r="20*cm"  outer_r="70*cm"    phi0_offset="0.0*deg" />
-  <layer id="4" z="-40 *cm"  inner_r="20*cm"  outer_r="50.0*cm"  phi0_offset="0.0*deg" />
-  <layer id="5" z=" 40 *cm"  inner_r="20*cm"  outer_r="50.0*cm" phi0_offset="0.0*deg" />
+  <layer id="4" z="-40 *cm"  inner_r="10*cm"  outer_r="20.0*cm"  phi0_offset="0.0*deg" />
+  <layer id="5" z=" 40 *cm"  inner_r="10*cm"  outer_r="20.0*cm" phi0_offset="0.0*deg" />
   <layer id="6" z=" 60 *cm"  inner_r="25*cm"  outer_r="70.0*cm" phi0_offset="0.0*deg" />
   <layer id="7" z=" 80 *cm"  inner_r="30*cm"  outer_r="90.0*cm" phi0_offset="0.0*deg" />
   <layer id="8" z="100 *cm"  inner_r="40*cm"  outer_r="100.0*cm" phi0_offset="0.0*deg" />
@@ -100,6 +100,13 @@ Or if there are too many constants to dump, try searching:
 npdet_info search world --all gem_tracker.xml
 ```
 
+```bash
+world_side                     =     1000.000 = 10*m
+world_x                        =     1000.000 = world_side
+world_y                        =     1000.000 = world_side
+world_z                        =    10000.000 = 10*world_side
+```
+
 This is very useful with a good subsystem naming convention.