can compute separate gas damping for ITMs and ETMs

gwinc/ifo/aLIGO/ifo.yaml

@@ -53,8 +53,11 @@ Infrastructure:
     SqueezedFilm:
       # Excess gas damping due to compensation plates and reaction masses
       # Numbers are rough guesses from LIGO-T0900582
-      ExcessDamping: 1.33    # excess force noise at DC; section 6
-      DiffusionTime: 800e-6  # s; diffusion time; section 4
+      ETM:
+        ExcessDamping: 1.33    # excess force noise at DC; section 6
+        DiffusionTime: 800e-6  # s; diffusion time; section 4
+      ITM:
+        gap: 20e-3  # m; gap between ITMs and compensation plates
 
 
 TCS:

gwinc/ifo/noises.py

@@ -846,9 +846,10 @@ class ExcessGasDampingH2(nb.Noise):
     @nb.precomp(sustf=precomp_suspension)
     def calc(self, sustf):
         species = self.ifo.Infrastructure.ResidualGas.H2
-        n = noise.residualgas.residual_gas_damping(
-            self.freq, self.ifo, species, sustf)
-        return 4 * n
+        # n = noise.residualgas.residual_gas_damping(
+        #     self.freq, self.ifo, species, sustf)
+        # return 4 * n
+        return _calc_residual_gas_damping(self.freq, self.ifo, species, sustf)
 
 
 class ExcessGasDampingN2(nb.Noise):
@@ -864,10 +865,10 @@ class ExcessGasDampingN2(nb.Noise):
     @nb.precomp(sustf=precomp_suspension)
     def calc(self, sustf):
         species = self.ifo.Infrastructure.ResidualGas.N2
-        n = noise.residualgas.residual_gas_damping(
-            self.freq, self.ifo, species, sustf)
-        return 4 * n
-
+        # n = noise.residualgas.residual_gas_damping(
+        #     self.freq, self.ifo, species, sustf)
+        # return 4 * n
+        return _calc_residual_gas_damping(self.freq, self.ifo, species, sustf)
 
 class ExcessGasDampingH2O(nb.Noise):
     """Excess gas damping for H2O
@@ -882,6 +883,34 @@ class ExcessGasDampingH2O(nb.Noise):
     @nb.precomp(sustf=precomp_suspension)
     def calc(self, sustf):
         species = self.ifo.Infrastructure.ResidualGas.H2O
-        n = noise.residualgas.residual_gas_damping(
-            self.freq, self.ifo, species, sustf)
-        return 4 * n
+        # n = noise.residualgas.residual_gas_damping(
+        #     self.freq, self.ifo, species, sustf)
+        # return 4 * n
+        return _calc_residual_gas_damping(self.freq, self.ifo, species, sustf)
+
+
+def _calc_residual_gas_damping(f, ifo, species, sustf):
+    """Redundant calculation of res gas damping for each species
+
+    Can get rid of if budgets are calculated at runtime
+    """
+    squeezed_film = ifo.Infrastructure.ResidualGas.get('SqueezedFilm', None)
+    if squeezed_film:
+        if 'ETM' in squeezed_film and 'ITM' in squeezed_film:
+            n_ETM = noise.residualgas.residual_gas_damping(
+                f, ifo, species, sustf, squeezed_film.ETM)
+
+            n_ITM = noise.residualgas.residual_gas_damping(
+                f, ifo, species, sustf, squeezed_film.ITM)
+
+            n = 2 * (n_ETM + n_ITM)
+
+        else:
+            n = 4 * noise.residualgas.residual_gas_damping(
+                f, ifo, species, sustf, squeezed_film)
+
+    else:
+        n = 4 * noise.residualgas.residual_gas_damping(
+            f, ifo, species, sustf, squeezed_film)
+
+    return n

gwinc/noise/residualgas.py

@@ -57,13 +57,14 @@ def residual_gas_scattering(f, ifo, cavity, species):
     return zint
 
 
-def residual_gas_damping(f, ifo, species, sustf):
+def residual_gas_damping(f, ifo, species, sustf, squeezed_film):
     """Noise due to residual gas damping for one test mass
 
     :f: frequency array in Hz
     :ifo: gwinc IFO structure
     :species: molecular species structure
     :sustf: suspension transfer function structure
+    :squeezed_film: squeezed film damping structure
 
     :returns: displacement noise
     """
@@ -90,9 +91,7 @@ def residual_gas_damping(f, ifo, species, sustf):
 
     # add squeezed film damping if necessary as parametrized by
     # Eq (5) of http://dx.doi.org/10.1103/PhysRevD.84.063007
-    if 'SqueezedFilm' in ifo.Infrastructure.ResidualGas:
-        squeezed_film = ifo.Infrastructure.ResidualGas.SqueezedFilm
-
+    if squeezed_film:
         # the excess force noise and diffusion time are specified directly
         if 'ExcessDamping' in squeezed_film:
             # ExcessDamping is the ratio of the total gas damping noise at DC