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Status for the Quartz BarsY. Horii, Y. Koga, N. Kiribe(Nagoya University, Japan)1PID Upgrade Meeting, 16th JuneOverview of our outcomes2Test for Sprasil-P20 bar from Okamoto (used for 10 beam test)using laser ( = 405 nm).

Bulk transmissionI0 / I0 = (100.0 0.8) %/m.Indicates no significant photon loss.No position dependence so far.

Reflections from glue joint(I2 + I3) / I1 = (0.22 0.00) % for = 2.Nontrivial source of the background.Better to include in the simulationand in the PDF calculation.Glue (NOA63)n ~ 1.57Quartzn = 1.47Quartzn = 1.47Details reported on 27th May.MirrorI1I2I3I0I0Position dependence for reflections from glue3

5 cm10 cm15 cm20 cmgluemirrorglueIncidence to the points5, 10, 15, and 20 cm from the edge.Relative positions of the two outputs are slightlychanged depending on the incident position.We cannot compare absolute positions since we changedthe CCD position each time (Angle not changed.)CCD4gluemirrorglueLaser12

~90 cm~150 cmRatio of the distancesafter the reflection = 3 : 8Ratio of the distancesof the means = 3 : 8Corresponds to the surface irregularityof the quartz of O(0.1) mrad.For checking the reason, we measuredreflected lights at two points (1 and 2).Distances obtained by 2-D fit (see backup slide).12Spec. of the bar (from Okamoto)5

Bending of O(0.1) mrad can easily be made.Orthogonality is30 for surface A and B.Surface irregularity is 1 mm.Note6

Local irregularity is O(1) .Global irregularity is O(1) mm.

We need to keep in mindthat the global irregularityis O(1) mm.Issues7Test for Zygo, Okamoto, and OSI materials.BulkBulk transmission (photon retainment)Mean and width of the laser spot (mean and width at PMT)SurfaceSurface reflectivity (photon retainment)Mean and width of the reflected spot (mean and width at PMT)MirrorReflectivity (photon retainment)Mean and width of the reflected spot (mean and width at PMT)GlueRefraction index (reflections at glue joints provide backgrounds)Position dependence for all measurements.Numerical estimation of the effect of each source to PID power.When should we make a decisionfor Zygo, Okamoto, and OSI?8Overview of the jig for gluingRails.Lower Al plateVinyl chloride plateQuartz barUpper Al plateMicrometersJig on a optical table of 4 m x 1.5 m.Size suitable for 130 cm bars(maximum of the bar production).Similar systems for the jointsof mirror/bar and wedge/bar.(Position adjustable on the rails.)(Position adjustable using micrometers.)(Surface irregularity < 100 mm.)(Placed for avoiding quartz-Al contact.)(Placed on polyacetal balls.)Zoom in.9Quartz bar is placed on the polyacetal balls (soft).Bending of quartz bar is estimated to be ~1 mm. (Similar level to surface irregularity.)Polyacetal ballsJig for adjusting and keepingposition and angles of quartz.Push using polyacetal head.Plunger spring.Plunger spring.Push using polyacetal head.Push using polyacetal head.Push using polyacetal head.Benchmark10Dx, Dy < O(10) mm.Photon loss is less than O(10) mm / 2.0 cm = O(0.1) %.Achieved by laser displacement sensors.

Dq < O(0.1) mrad.Position difference of the photon at PMTis typically < O(0.1) mm (smaller than thePMT channel size 5.3 mm x 5.3 mm).Time difference of the photon at PMTis typically < O(0.1) psec (smaller thanthe PMT resolution ~ 40 psec).Achieved by autocollimator.DqConservatively high quality.Plan11

Design and offer the jig for the joint.JuneWeek 3Week 4Week 5Week 1Week 2Week 3Week 4JulyJoint the quartz bars.Quartz quality check.Quartz quality check.Busy with BGM/B2GMJoint the mock-up (glass) bars.Backup slides12Obtain the distance by 2-D fit.13

12Dx = 0.61 mmDy = 0.18 mmDx = 1.67 mmDy = 0.51 mm3:8datadataMCMCBending of quartz14Assume that the bar relies only on two polyacetal balls.

Flexures at the edges and the central point are O(1) mm.

L1 cmL1 cmIn reality, we use ~100 balls per bar. Then the flexure will be less than 1 mm.Calculation usingwell-known effective equation.