Set a one-meter absorption length for the fused silica MPT

The absorption length spectrum data which was used before may not apply for JGS2 fused silica. The data used before was commented out, but kept in the .cc file.

Author: jurenag

source/materials/OpticalMaterialProperties.cc

@@ -137,29 +137,55 @@ namespace opticalprops {
     // the real and the imaginary part) are shown. The absorption length is computed
     // out of such data as vacuum_wavelength_cm/(4*pi*k), where k is the imaginary
     // part of the refractive index.
+    // std::vector<G4double> abs_energy = {
+    //   optPhotMinE_,
+    //   h_Planck * c_light / (880.0 * nm), h_Planck * c_light / (840.0 * nm), h_Planck * c_light / (800.0 * nm),
+    //   h_Planck * c_light / (780.0 * nm), h_Planck * c_light / (760.0 * nm), h_Planck * c_light / (740.0 * nm),
+    //   h_Planck * c_light / (720.0 * nm), h_Planck * c_light / (700.0 * nm), h_Planck * c_light / (680.0 * nm),
+    //   h_Planck * c_light / (660.0 * nm), h_Planck * c_light / (640.0 * nm), h_Planck * c_light / (620.0 * nm),
+    //   h_Planck * c_light / (600.0 * nm), h_Planck * c_light / (580.0 * nm), h_Planck * c_light / (560.0 * nm),
+    //   h_Planck * c_light / (540.0 * nm), h_Planck * c_light / (520.0 * nm), h_Planck * c_light / (500.0 * nm),
+    //   h_Planck * c_light / (480.0 * nm), h_Planck * c_light / (460.0 * nm), h_Planck * c_light / (440.0 * nm),
+    //   h_Planck * c_light / (420.0 * nm), h_Planck * c_light / (400.0 * nm), h_Planck * c_light / (380.0 * nm),
+    //   h_Planck * c_light / (360.0 * nm), h_Planck * c_light / (340.0 * nm), h_Planck * c_light / (320.0 * nm),
+    //   h_Planck * c_light / (300.0 * nm), h_Planck * c_light / (280.0 * nm), h_Planck * c_light / (260.0 * nm),
+    //   h_Planck * c_light / (240.0 * nm), h_Planck * c_light / (220.0 * nm), h_Planck * c_light / (200.0 * nm),
+    //   optPhotMaxE_
+    // };
+
+    // std::vector<G4double> absLength = {
+    //   noAbsLength_,
+    //   140.056 * cm, 83.556 * cm, 48.97 * cm, 47.746 * cm, 50.399 * cm, 49.072 * cm, 47.746 * cm, 50.64 * cm,
+    //   54.112 * cm, 47.746 * cm, 56.588 * cm, 61.672 * cm, 59.683 * cm, 57.693 * cm, 55.704 * cm, 53.714 * cm,
+    //   59.114 * cm, 49.735 * cm, 47.746 * cm, 52.293 * cm, 50.02 * cm, 47.746 * cm, 45.472 * cm, 27.49 * cm,
+    //   19.098 * cm, 6.937 * cm, 1.571 * cm, 0.356 * cm, 0.096 * cm, 0.099 * cm, 0.097 * cm, 0.096 * cm,
+    //   0.117 * cm,
+    //   0.0
+    // };
+
+    // ABSORPTION LENGTH
+    // The data above may not apply for the JGS2 fused silica (FS), which is particularly good for UV
+    // transmission (although worse than JGS3). This, together with the fact that I did not find a
+    // reliable measurement of the JGS2 FS absorption length, are the reasons why I've decided to use
+    // just a constant 1 meter absorption length for fused silica in the [280-700] nm band. The lower
+    // limit (280 nm) follows from the fact that, in
+    // https://www.universitywafer.com/Wafers_Services/Fused_Silica/fused_silica.html?srsltid=AfmBOormBlC3IKATTTE3NcN2hOikdPNQZNkvhmniTkROvvpfIFe1umSx ,
+    // the JGS2 transmitance as of 280 nm is >~90% which is basically the Fresnel transmitance. I.e.
+    // as of 280 nm, the absorption length must be >>1mm, which is the typical thickness of the wafers
+    // for which these plots apply.
     std::vector<G4double> abs_energy = {
       optPhotMinE_,
-      h_Planck * c_light / (880.0 * nm), h_Planck * c_light / (840.0 * nm), h_Planck * c_light / (800.0 * nm),
-      h_Planck * c_light / (780.0 * nm), h_Planck * c_light / (760.0 * nm), h_Planck * c_light / (740.0 * nm),
-      h_Planck * c_light / (720.0 * nm), h_Planck * c_light / (700.0 * nm), h_Planck * c_light / (680.0 * nm),
-      h_Planck * c_light / (660.0 * nm), h_Planck * c_light / (640.0 * nm), h_Planck * c_light / (620.0 * nm),
-      h_Planck * c_light / (600.0 * nm), h_Planck * c_light / (580.0 * nm), h_Planck * c_light / (560.0 * nm),
-      h_Planck * c_light / (540.0 * nm), h_Planck * c_light / (520.0 * nm), h_Planck * c_light / (500.0 * nm),
-      h_Planck * c_light / (480.0 * nm), h_Planck * c_light / (460.0 * nm), h_Planck * c_light / (440.0 * nm),
-      h_Planck * c_light / (420.0 * nm), h_Planck * c_light / (400.0 * nm), h_Planck * c_light / (380.0 * nm),
-      h_Planck * c_light / (360.0 * nm), h_Planck * c_light / (340.0 * nm), h_Planck * c_light / (320.0 * nm),
-      h_Planck * c_light / (300.0 * nm), h_Planck * c_light / (280.0 * nm), h_Planck * c_light / (260.0 * nm),
-      h_Planck * c_light / (240.0 * nm), h_Planck * c_light / (220.0 * nm), h_Planck * c_light / (200.0 * nm),
+      // Fixing the absorption length at 700 nm
+      h_Planck * c_light / (701.0 * nm), h_Planck * c_light / (700.0 * nm), h_Planck * c_light / (699.0 * nm),
+      // Fixing the absorption length at 220 nm
+      h_Planck * c_light / (221.0 * nm), h_Planck * c_light / (220.0 * nm), h_Planck * c_light / (219.0 * nm),
       optPhotMaxE_
     };
 
     std::vector<G4double> absLength = {
-      noAbsLength_,
-      140.056 * cm, 83.556 * cm, 48.97 * cm, 47.746 * cm, 50.399 * cm, 49.072 * cm, 47.746 * cm, 50.64 * cm,
-      54.112 * cm, 47.746 * cm, 56.588 * cm, 61.672 * cm, 59.683 * cm, 57.693 * cm, 55.704 * cm, 53.714 * cm,
-      59.114 * cm, 49.735 * cm, 47.746 * cm, 52.293 * cm, 50.02 * cm, 47.746 * cm, 45.472 * cm, 27.49 * cm,
-      19.098 * cm, 6.937 * cm, 1.571 * cm, 0.356 * cm, 0.096 * cm, 0.099 * cm, 0.097 * cm, 0.096 * cm,
-      0.117 * cm,
+      1. * m,
+      1. * m, 1. * m, 1. * m,
+      1. * m, 1. * m, 1. * m,
       0.0
     };