Status for the Quartz Bars Y. Horii, Y. Koga, N. Kiribe (Nagoya University, Japan) 1 PID Upgrade Meeting, 16 th June

Overview of our outcomes 2  Test for Sprasil-P20 bar from Okamoto (used for ’10 beam test) using laser ( λ = 405 nm).  Bulk transmission  I 0 ’ / I 0 = (100.0 ± 0.8) %/m.  Indicates no significant photon loss.  No position dependence so far.  Reflections from glue joint  (I 2 + I 3 ) / I 1 = (0.22 ± 0.00) % for α = 2°.  Nontrivial source of the background.  Better to include in the simulation and in the PDF calculation. Glue (NOA63) n ~ 1.57 Quartz n = 1.47 Quartz n = 1.47 Details reported on 27 th May. Mirror I1I1 I2I2 I3I3 I0I0 I0’I0’ α

Position dependence for reflections from glue 3 5 cm10 cm 15 cm20 cm glue mirror glue Incidence to the points 5, 10, 15, and 20 cm from the edge. Relative positions of the two outputs are slightly changed depending on the incident position. We cannot compare absolute positions since we changed the CCD position each time… (Angle not changed.) CCD

4 glue mirror glue Laser1 2 ~90 cm ~150 cm Ratio of the distances after the reflection = 3 : 8 Ratio of the distances of the means = 3 : 8 Corresponds to the surface irregularity of the quartz of O(0.1) mrad. For checking the reason, we measured reflected lights at two points (1 and 2). Distances obtained by 2-D fit (see backup slide). 1 2

Spec. of the bar (from Okamoto) 5 Bending of O(0.1) mrad can easily be made. Orthogonality is ±30’’ for surface A and B. Surface irregularity is 1  m.

Note 6 Local irregularity is O(1) Å. Global irregularity is O(1)  m. We need to keep in mind that the global irregularity is O(1)  m.

Issues 7  Test for Zygo, Okamoto, and OSI materials.  Bulk  Bulk transmission (  photon retainment)  Mean and width of the laser spot (  mean and width at PMT)  Surface  Surface reflectivity (  photon retainment)  Mean and width of the reflected spot (  mean and width at PMT)  Mirror  Reflectivity (  photon retainment)  Mean and width of the reflected spot (  mean and width at PMT)  Glue  Refraction 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 decision for Zygo, Okamoto, and OSI…?

8 Overview of the jig for gluing Rails. Lower Al plate Vinyl chloride plate Quartz bar Upper Al plate Micrometers Jig 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 joints of mirror/bar and wedge/bar. (Position adjustable on the rails.) (Position adjustable using micrometers.) (Surface irregularity < 100  m.) (Placed for avoiding quartz-Al contact.) (Placed on polyacetal balls.)

Zoom in. 9 Quartz bar is placed on the polyacetal balls (soft). Bending of quartz bar is estimated to be ~1  m. (Similar level to surface irregularity.) Polyacetal balls Jig for adjusting and keeping position and angles of quartz. Push using polyacetal head. Plunger spring. Push using polyacetal head.

Benchmark 10   x,  y < O(10)  m.  Photon loss is less than O(10)  m / 2.0 cm = O(0.1) %.  Achieved by laser displacement sensors.   < O(0.1) mrad.  Position difference of the photon at PMT is typically < O(0.1) mm (smaller than the PMT channel size 5.3 mm x 5.3 mm).  Time difference of the photon at PMT is typically < O(0.1) psec (smaller than the PMT resolution ~ 40 psec).  Achieved by autocollimator.  Conservatively high quality.

Plan 11 Design and offer the jig for the joint.JuneWeek 3 Week 4 Week 5 Week 1 Week 2 Week 3 Week 4 July Joint the quartz bars. Quartz quality check. Busy with BGM/B2GM Joint the mock-up (glass) bars.

Backup slides 12

Obtain the distance by 2-D fit  x = 0.61 mm  y = 0.18 mm  x = 1.67 mm  y = 0.51 mm 3:83:8 data MC

Bending of quartz 14  Assume that the bar relies only on two polyacetal balls.  Flexures at the edges and the central point are O(1)  m. L1 cm In reality, we use ~100 balls per bar. Then the flexure will be less than 1  m. Calculation using well-known effective equation.