Quartz preparation (quality check and prototype status). BPAC, 12th Nov. 2011. Y. Horii (Nagoya University). Introduction. The quartz bars must transmit Cherenkov photons over long optical length with a number of internal reflections . In this talk, we show - PowerPoint PPT Presentation
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Quartz preparation
(quality check and prototype status)Y. Horii (Nagoya
University)1BPAC, 12th Nov. 2011Introduction2The quartz bars must
transmit Cherenkov photons over long optical length with a number
of internal reflections.
In this talk, we showoptical qualities of the bars andstatus of
preparing prototype for the beam test.
Examples of photon paths inprototype for beam test in
2010.3Quality checkOptical properties4Number of photonsResolution
of Cherenkov angle naively depends on square root of number of
photons.Require to retain 80% after bulk transmittance and
reflections.
Photon-path shiftsResolution of Cherenkov angledepends on
photon-path shifts.Require the shift to be < 0.5 mradafter
reflections and by striae.
Quartz bars5
Suprasil-P710 polished by Okamoto Co.Corning 7980 0D polished by
Zygo Co.131 x 45 x 2 cm2120 x 45 x 2 cm2Highest striae gradein
MIL-G-174 standardHighest striae gradein ISO 10110-4
standardSpecificationActualRequireRoughness (nm
rms)0.440.5Squareness (arc min.)0.171Flatness S6, S5 (mm)2.0,
2.025Flatness S4, S3 (mm)0.8, 0.96.3Flatness S1, S2 (mm)4.9,
5.16.3SpecificationActualRequireRoughness (nm rms)0.40.5Squareness
(arc min.)0.1-3.85Flatness A, B (mm)0.8, 0.91.3Flatness C, D
(mm)0.9, 1.11.3Flatness E, F (mm)2.6, 3.06.3Better flatnessBetter
squareness in generalEquipments for checking quality of bars6
Laser:Wavelength = 405 nm(typical for TOP).Prism splitter and
reference PDto calibrate fluctuations.Position adjustable on
motorizedstages with a precision of O(mm).
Photodiode:efficiency stable forat least 6 x 6 mm2.
CCD:4.4 x 4.4 mm2/pixel.1600 x 1200 pixels.Position adjustable
onmotorized stages witha precision of O(mm).Bulk transmittance7
Bulk transmittance t obtained usingintensities I0 and I1
measured by PDand reflectances R0 and R1 calculated.7 x 5 incident
points.Suprasil-P710: Ave. = 99.44%/m Max. = 99.57%/m Min. =
99.27%/mCorning 7980 0D: Ave. = 99.35%/m Max. = 99.50%/m Min. =
99.25%/mRequirement: > 98%/m.For both bars, enough bulk
transmittance for all incident points.(Error of individual
measurement: 0.17%/m.)xyzInternal surface reflectance8Measure the
reflectance for several angles of reflections in 56-70.
For both bars, enough reflectance for interested
angles.Requirement: > 99.90%.
Surface reflectance a obtained usingintensities I0 and I1
measured by PD,reflectances R0 and R1 calculated,and the
exponential of bulk transmittance.N: number of bouncesL/b:
length/thickness of barL: coefficient of bulk
transmittanceSuprasil-P710: Max. = 99.98% Min. = 99.92%Corning 7980
0D: Max. = 99.97% Min. = 99.92%zy(Error: 0.02%.)Possible effect of
striae9Data taken by CCD.
Bitmap (histogram) fitted with 2-D Gauss + 2-D linear.
Scan the positions of laser/CCD simultaneously in y
direction.
Means and widths of 2-D Gauss in interest.Scan.zy
yxPossible effect of striae10Requirement: path shift < 0.5
mrad.Corning 7980 0D polished by ZygoThese path shifts can be
explained by surface non-flatness. Effects of striae smaller.
Mean in y direction most significantly fluctuates for both
bars.Path shift within 0.15 mradPath shift within 0.33
mradSuprasil-P710 polished by Okamotoy > 20 mm:laser through
air.
Displacement btwy < 20 and > 20 mm:due to deviation
ofincident angle from 0.Possible effect of striae11Other checks:No
larger path shifts for other x positions.No larger path shifts for
another incident angle of 30.No larger path shifts for scan of
laser/CCD in x direction.Finer scan for estimating finer periodic
structure of striae:
Larger variation for y width.But still can be explainedby
surface non-flatness.No significant effect for PID.12Glue the
bars/mirrorStrategy of the gluing13Put the Okamoto bar downstream
of photon path since squareness of Okamoto bar is worse.
Use glue of NOA63 for bar-bar joint (higher viscosity).Use glue
of NBA107 for mirror (temporary since mirror is smaller).
14Jig for gluing
Control of angles and positions15Relative angle of barsAdjust
using micrometerheads.
Measure using autocollimator.Relative position of barsAdjust
using polyacetal headsand plungers.
Measure using laser sensor.
Precision = 0.01 mrad, requirement = 0.2 mrad.
Precision = 5 mm, requirement = 100 mm.
Gluing16
Put glue using dispenser (head is soft).
Glue goes down. Takes ~1 hour.Cured by UV light. Takes
99.90%.
Angle ofincidence ()Angle ofreflection ()Numberof
bouncesReflectance afor Suprasil-P710 (%)Reflectance afor Corning
7980 0D (%)56564599.95 0.0199.92 0.0150593999.96 +0.020.0199.93
0.0145613599.97 +0.020.0199.93 0.0139653199.92 +0.020.0199.93
0.0135672799.96 +0.020.0199.93 0.0130702399.98 +0.020.0199.97
+0.020.01Roughness25Roughness and reflectance are related by a
scalar scattering theory:
d: RMS of roughnessq: angle of reflectancel: wavelength of
laser
Okamoto bar:d = (12 4) Zygo bar:d = (17 4) Possible effect of
striae26Requirement: path shift < 0.5 mrad.Suprasil-P710
polished by OkamotoCorning 7980 0Dpolished by Zygo
Results corresponds to path shift < 0.3 mrad. Can be
explained by surface non-flatness.
LaserCCDS6S5Quartz
bluegreenmeasured by ZygoSurface non-flatness and path
shifts27zy0.1-0.3 mrad shift can be generated.27Quality check of
the mirror28In addition to the bars, we do several checks for the
mirror.
Bulk transmittanceReflectance at quartz-AlResult = (99.20
0.38)%Result = (88.5 0.2)%Safely large.Will require better value
for TOP.29Jig for gluingRails.Lower Al plateVinyl chloride
plateQuartz barUpper Al plateMicrometers(Position adjustable on the
rails.)(Position adjustable using micrometers.)(Surface flatness
< 100 mm.)(Placed for avoiding quartz-Al contact.)(Placed on
polyacetal balls.)30
Lower Al plateUpper Al plateand micrometer-head
Overall configuration (one bar)31
Plunger to keepthe position of the bar.
Polyacetal head to adjustthe position of the bar.
Bar, polyacetal balls, and plastic plate.Flatness of the
bars32Flatness of the bars after adjusting the angles and positions
is measured by using autocollimator.
The flatness is safely nice for the gluing.
Suprasil-P710Corning 7980
Incident y position (mm)0 5 10 15 20 25 30
Y m
ean
with
resp
ect t
o CC
D (m
m)
1.5
2
2.5
3
3.5
4
4.5
5
Incident y position (mm)0 5 10 15 20 25 30
Y wi
dth
(mm
)
0.2
0.22
0.24
0.26
0.28
0.3
0.32
0.34
0.36
0.38
0.4
Incident y position (mm)0 5 10 15 20 25 30
X m
ean
with
resp
ect t
o CC
D (m
m)
1.5
2
2.5
3
3.5
4
4.5
5
Incident y position (mm)0 5 10 15 20 25 30
X wi
dth
(mm
)
0.2
0.22
0.24
0.26
0.28
0.3
0.32
0.34
0.36
0.38
0.4
Incident y position (mm)0 5 10 15 20 25 30
Y m
ean
with
resp
ect t
o CC
D (m
m)
1.5
2
2.5
3
3.5
4
4.5
5
Incident y position (mm)0 5 10 15 20 25 30
Y wi
dth
(mm
)
0.2
0.22
0.24
0.26
0.28
0.3
0.32
0.34
0.36
0.38
0.4
Incident y position (mm)0 5 10 15 20 25 30
X m
ean
with
resp
ect t
o CC
D (m
m)
1.5
2
2.5
3
3.5
4
4.5
5
Incident y position (mm)0 5 10 15 20 25 30
X wi
dth
(mm
)
0.2
0.22
0.24
0.26
0.28
0.3
0.32
0.34
0.36
0.38
0.4
