From 95bfb2a85d1defd64f3749f1090b26687e58d3be Mon Sep 17 00:00:00 2001
From: Christopher Wipf <wipf@ligo.mit.edu>
Date: Mon, 13 Aug 2018 13:59:35 -0700
Subject: [PATCH] aLIGO.yaml: updated parameters from matgwinc IFOModel
(addresses #23)
---
gwinc/ifo/aLIGO.yaml | 108 ++++++++++++++++++-------------------------
1 file changed, 46 insertions(+), 62 deletions(-)
diff --git a/gwinc/ifo/aLIGO.yaml b/gwinc/ifo/aLIGO.yaml
index ea588e5a..75b3a611 100644
--- a/gwinc/ifo/aLIGO.yaml
+++ b/gwinc/ifo/aLIGO.yaml
@@ -38,6 +38,18 @@ Infrastructure:
polarizability: 7.8e-31 # m^3
TCS:
+ # The presumably dominant effect of a thermal lens in the ITMs is an increased
+ # mode mismatch into the SRC, and thus an increased effective loss of the SRC.
+ # The increase is estimated by calculating the round-trip loss S in the SRC as
+ # 1-S = |<Psi|exp(i*phi)|Psi>|^2, where
+ # |Psi> is the beam hitting the ITM and
+ # phi = P_coat*phi_coat + P_subs*phi_subs
+ # with phi_coat & phi_subs the specific lensing profiles
+ # and P_coat & P_subst the power absorbed in coating and substrate
+ #
+ # This expression can be expanded to 2nd order and is given by
+ # S= s_cc P_coat^2 + 2*s_cs*P_coat*P_subst + s_ss*P_subst^2
+ # s_cc, s_cs and s_ss were calculated analytically by Phil Willems (4/2007)
s_cc: 7.024 # Watt^-2
s_cs: 7.321 # Watt^-2
s_ss: 7.631 # Watt^-2
@@ -56,6 +68,7 @@ TCS:
Seismic:
Site: 'LHO' # LHO or LLO (only used for Newtonian noise)
+ # darmSeiSusFile: 'seismic.mat' # .mat file containing predictions for darm displacement
KneeFrequency: 10 # Hz; freq where 'flat' noise rolls off
LowFrequencyLevel: 1e-9 # m/rtHz; seismic noise level below f_knee
Gamma: 0.8 # abruptness of change at f_knee
@@ -68,20 +81,20 @@ Seismic:
Suspension:
Type: 'Quad'
- FiberType: 'Round'
+ FiberType: 'Tapered'
BreakStress: 750e6 # Pa; ref. K. Strain
Temp: 290
- VHCoupling:
- theta: 1e-3 # vertical-horizontal x-coupling
+ # VHCoupling:
+ # theta: 1e-3 # vertical-horizontal x-coupling (computed in precompIFO)
Silica:
- Rho : 2200 # Kg/m^3;
+ Rho : 2.2e3 # Kg/m^3;
C : 772 # J/Kg/K;
K : 1.38 # W/m/kg;
Alpha : 3.9e-7 # 1/K;
dlnEdT: 1.52e-4 # (1/K), dlnE/dT
Phi : 4.1e-10 # from G Harry e-mail to NAR 27April06 dimensionless units
- Y : 72e9 # Pa; Youngs Modulus
+ Y : 7.2e10 # Pa; Youngs Modulus
Dissdepth: 1.5e-2 # from G Harry e-mail to NAR 27April06
C70Steel:
@@ -102,18 +115,18 @@ Suspension:
Phi: 1e-4
Y: 187e9
- # ref ---- http://design.caltech.edu/Research/MEMS/siliconprop.html
- # all properties should be for T ~ 20 K
+ # ref http://www.ioffe.ru/SVA/NSM/Semicond/Si/index.html
+ # all properties should be for T ~ 120 K
Silicon:
- Rho: 2330 # Kg/m^3; density
- C: 772 # J/kg/K heat capacity
- K: 4980 # W/m/K thermal conductivity
- Alpha: 1e-9 # 1/K thermal expansion coeff
+ Rho: 2329 # Kg/m^3; density
+ C: 300 # J/kg/K heat capacity
+ K: 700 # W/m/K thermal conductivity
+ Alpha: 1e-10 # 1/K thermal expansion coeff
# from Gysin, et. al. PRB (2004) E(T): E0 - B*T*exp(-T0/T)
# E0: 167.5e9 Pa T0: 317 K B: 15.8e6 Pa/K
- dlnEdT: 2.5e-10 # (1/K) dlnE/dT T=20K
+ dlnEdT: -2e-5 # (1/K) dlnE/dT T=120K
Phi: 2e-9 # Nawrodt (2010) loss angle 1/Q
- Y: 150e9 # Pa Youngs Modulus
+ Y: 155.8e9 # Pa Youngs Modulus
Dissdepth: 1.5e-3 # 10x smaller surface loss depth (Nawrodt (2010))
# Note stage numbering: mirror is at beginning of stack, not end
@@ -124,6 +137,9 @@ Suspension:
Stage:
# Stage1
- Mass: 39.6 # kg; current numbers May 2006 NAR
+ # length adjusted for d = 10mm and d_bend = 4mm
+ # (since 602mm is the CoM separation, and d_bend is accounted for
+ # in suspQuad, so including it here would double count)
Length: 0.59 # m
Dilution: .nan #
K: .nan # N/m; vertical spring constant
@@ -164,7 +180,11 @@ Suspension:
Fiber:
Radius: 205e-6 # m
- Blade: 4300e-6
+ # for tapered fibers
+ # EndRadius is tuned to cancel thermo-elastic noise (delta_h in suspQuad)
+ # EndLength is tuned to match bounce mode frequency
+ EndRadius: 400e-6 # m; nominal 400um
+ EndLength: 45e-3 # m; nominal 20mm
## Optic Material -------------------------------------------------------
Materials:
@@ -174,14 +194,15 @@ Materials:
## Dielectric coating material parameters----------------------------------
Coating:
## high index material: tantala
- Yhighn: 140e9
- Sigmahighn: 0.23
+ Yhighn: 124e9 # LMA (Granata at LVC) 2017 (was 140)
+ Sigmahighn: 0.28 # LMA (Granata at LVC) 2017 (was 0.23)
CVhighn: 2.1e6 # Crooks et al, Fejer et al
Alphahighn: 3.6e-6 # 3.6e-6 Fejer et al, 5e-6 from Braginsky
Betahighn: 1.4e-5 # dn/dT, value Gretarrson (G070161)
ThermalDiffusivityhighn: 33 # Fejer et al
- Phihighn: 3.6e-4 # tantala mechanical loss
Indexhighn: 2.06539
+ Phihighn: 3.6e-4 # loss angle at 100Hz (Gras 2018)
+ Phihighn_slope: 0.1
## low index material: silica
Ylown: 72e9
@@ -190,11 +211,13 @@ Materials:
Alphalown: 5.1e-7 # Fejer et al
Betalown: 8e-6 # dn/dT, (ref. 14)
ThermalDiffusivitylown: 1.38 # Fejer et al
- Philown: 5.0e-5 # silica mechanical loss
Indexlown: 1.45
+ Philown: 5.0e-5 # loss angle at 100Hz (was 4.0e-5)
+ Philown_slope: 0.4
## Substrate Material parameters--------------------------------------------
Substrate:
+ Temp: 295
c2 : 7.6e-12 # Coeff of freq depend. term for bulk mechanical loss, 7.15e-12 for Sup2
MechanicalLossExponent: 0.77 # Exponent for freq dependence of silica loss, 0.822 for Sup2
Alphas: 5.2e-12 # Surface loss limit (ref. 12)
@@ -215,25 +238,23 @@ Laser:
Optics:
Type: 'SignalRecycled'
PhotoDetectorEfficiency: 0.9 # photo-detector quantum efficiency
- Loss: 37.5e-6 # average per mirror power loss
+ Loss: 40e-6 # average per mirror power loss
BSLoss: 0.5e-3 # power loss near beamsplitter
coupling: 1.0 # mismatch btwn arms & SRC modes; used to
-
- #SubstrateAbsorption: 0.5e-4 # 1/m; bulk absorption coef (ref. 2)
- SubstrateAbsorption: 0.3e-4 # 1/m; 0.3 ppm/cm for Hereaus
+ # calculate an effective r_srm
+ SubstrateAbsorption: 0.5e-4 # 1/m; bulk absorption coef (ref. 2)
pcrit: 10 # W; tolerable heating power (factor 1 ATC)
Quadrature:
dc: 1.5707963 # pi/2 # demod/detection/homodyne phase
ITM:
- BeamRadius: 0.055 # m, 1/e^2 power radius
+ # BeamRadius: 0.055 # m, 1/e^2 power radius, now in precompIFO
Transmittance: 0.014
CoatingThicknessLown: 0.308
CoatingThicknessCap: 0.5
CoatingAbsorption: 0.5e-6
- SubstrateAbsorption: 0.3e-4 # 1/m, 0.3 ppm/cm for Hereaus
ETM:
- BeamRadius: 0.062 # m, 1/e^2 power radius
+ # BeamRadius: 0.062 # m, 1/e^2 power radius, now in precompIFO
Transmittance: 5e-6
CoatingThicknessLown: 0.27
CoatingThicknessCap: 0.5
@@ -247,40 +268,3 @@ Optics:
Curvature: # ROC
ITM: 1970
ETM: 2192
-
-## Squeezer Parameters------------------------------------------------------
-# Define the squeezing you want:
-# None: ignore the squeezer settings
-# Freq Independent: nothing special (no filter cavties)
-# Freq Dependent = applies the specified filter cavites
-# Optimal = find the best squeeze angle, assuming no output filtering
-# OptimalOptimal = optimal squeeze angle, assuming optimal readout phase
-Squeezer:
- Type: 'None'
- AmplitudedB: 10 # SQZ amplitude [dB]
- InjectionLoss: 0.05 # power loss to sqz
- SQZAngle: 0 # SQZ phase [radians]
-
- # Parameters for frequency dependent squeezing
- FilterCavity:
- fdetune: -14.5 # detuning [Hz]
- L: 100 # cavity length
- Ti: 0.12e-3 # input mirror trasmission [Power]
- Te: 0 # end mirror trasmission
- Lrt: 100e-6 # round-trip loss in the cavity
- Rot: 0 # phase rotation after cavity
-
-## Variational Output Parameters--------------------------------------------
-# Define the output filter cavity chain
-# None = ignore the output filter settings
-# Chain = apply filter cavity chain
-# Optimal = find the best readout phase
-OutputFilter:
- Type: 'None'
- FilterCavity:
- fdetune: -30 # detuning [Hz]
- L: 4000 # cavity length
- Ti: 10e-3 # input mirror trasmission [Power]
- Te: 0 # end mirror trasmission
- Lrt: 100e-6 # round-trip loss in the cavity
- Rot: 0 # phase rotation after cavity
--
GitLab