T1300716-v1 ACB Multi-AR coating on SS
8/27/13
Arm cavity power, W
radius of SS baffle edge, m
radius of SS baffle bend, m
length of baffle plate edge, m
length of baffle bend, m
Frontal area of SS center plate cut edge, m^2
Frontal area of SS baffle bend edge, m^2
BRDF of SS cut edge, sr^-1
BRDF of photodetector, sr^-1
BRDF of screw head sr^-1
number of photodetector
number of screw heads
photoconductor area, m^2
Screw head area, m^2
laser wavelength, m
wave number, m^-1
ACB displacement @ 100 HZ, m/rt HZ
IFO waist size, m
solid angle of IFO mode, sr
Transfer function @ 100 Hz, ITM HR
Gaussian beam radius at ITM, m
IFO arm length, m
PSL laser power, W
Arm Power, W
radius of Cryopump aperture, m
half-angle from centerline to Rcp, rad
half-angle from centerline to Rcp, rad (see ACB_PD_scatter_8-29-12)
BRDF, sr^-1; CSIRO, surface 2, S/N 2
radius of manifold/cryo baffle, m
height of ledge, m
radius of ACB hole, m
area of ACB hole, m^2
area of manifold/cryo baffle ledge, m^2
area of exposed ACB, m^2
power through the cryopump baffle aperture
(hits the arm cavity baffle), W
Area of cryopump baf aperture, m^2
incident intensity, W/m^2
tilt angle of baffle edge, rad
incident angle, rad
input angle range, bend, rad
input angle range, bend, deg
input angle range, edge rad
BRDF #4 Oxidized stainless steel, 3 deg inc.
Reflectivity of baffle surface
break-over angle, rad
micro-roughness angle, rad
max BRDF, sr^-1
final slope modifier
micro-roughness constant
large angle
BRDF function, sr^-1
BRDF #4 Oxidized stainless steel, 57 deg inc.
Reflectivity of baffle surface
break-over angle, rad
micro-roughness angle, rad
max BRDF, sr^-1
final slope modifier
micro-roughness constant
large angle
BRDF function, sr^-1
back-scatter angle, rad
back-scatter BRDF, sr^-1
BRDF Multi-AR 57 deg inc.
specular reflectivity
break-over angle, rad
micro-roughness angle, rad
max BRDF, sr^-1
final slope modifier
micro-roughness constant
large angle
BRDF function, sr^-1
back-scatter angle, rad
back-scatter BRDF, sr^-1
BRDF multi-AR 15 deg inc.
specular reflectivity
break-over angle, rad
micro-roughness angle, rad
max BRDF, sr^-1
final slope modifier
micro-roughness constant
large angle
BRDF function, sr^-1
back-scatter angle, rad
back-scatter BRDF, sr^-1
BRDF multi-AR 3 deg inc.
specular reflectivity
break-over angle, rad
micro-roughness angle, rad
max BRDF, sr^-1
final slope modifier
micro-roughness constant
large angle
BRDF function, sr^-1
back-scatter angle, rad
back-scatter BRDF, sr^-1
BRDF Summary
back-scatter BRDF, sr^-1
incident angle
back-scatter BRDF
Reflectance Summary
Reflectance
incident angle
ReflectanceDF
Scatter from photodetectors
number of photodetector
photoconductor area, m^2
Power hitting the PD, W
power scattered by photodetector,
into IFO mode, W
displacement noise @ 100 Hz, m/rtHz
Scatter from screw heads
number of screw heads
Screw head area, m^2
Power hitting the screw head, W
power scattered by screw head into IFO mode, W
displacement noise @ 100 Hz, m/rtHz
OXIDIZED SS BAFFLE
Scatter from oxy SS center plate edge
Scattered power into IFO from oxy SS center plate edge
displacement noise @ 100 Hz, m/rtHz
BRDF geometric scatter function from oxy baffle bend
incident angle, rad
Scattered power into IFO from oxy SS baffle bend
displacement noise @ 100 Hz, m/rtHz
Power Scattered from the louver portion of baffle
displacement noise @ 100 Hz, m/rtHz
Total scattered power into IFO from oxy SS ACB
Note: the louver scatter dominates for oxy SS surface with edge radius < 0.003 m
total displacement noise @ 100 Hz, m/rtHz
Multi-AR_SS BAFFLE
Scatter from mAR-SS center plate edge
BRDF geometric scatter function from mAR- SS center plate edge
incident angle, rad
Scattered
power
into IFO
from
mAR-SS
baffle
center plate
edge
displacement noise @ 100 Hz, m/rtHz
BRDF geometric scatter function from mAR-SS baffle bend
incident angle, rad
Scattered power into IFO from mAR-SS baffle bend
displacement noise @ 100 Hz, m/rtHz
Power Scattered from the mAR-SS louver portion of baffle
displacement noise @ 100 Hz, m/rtHz
Total scattered power into IFO from mAR-SS ACB
Reduce reduce screw head BRDF so that louver dominates the scatter
Tilt the baffle so that edge scatter does not dominate
Note: the edge scatter does not dominate for tilt angles >0.3 deg
Note: the screw head BRDF must be <
total displacement noise @ 100 Hz, m/rtHz
Comparison of mAR coated SS to oxidized SS bafle