Adds Material STS_PLA

Polylatic acid used for STS near beampipe cut section for mCBM 2022.

media.geo

@@ -1431,6 +1431,12 @@ STS_Cable_21	   1  54.938  25  0.5656
 		   0  1  20.  .001
 		   0
 
+// Polylatic Acid as specified by MT 20220707. 3D printed component.
+// (C3H4O2)n, with a density of 1.3 g/cm^3
+STS_PLA		   -3  1.0079  12.011  15.999  1.  6.  8. 1.3 4. 3. 2.
+                   0  1  20.  .001
+                   0
+
 tof_pole_aluminium 1  26.98 13. 2.7
                    0  1  20.  .001
                    0