Wide Angle Baffle Cooling Test 2018

Links to knowledge

• Wide Angle Baffle design review (Obuchi)

• Requirements for heat links of WAB (Akutsu)

• Temporal information links

• Wide Angle Baffle assembly-procedure manual (Zeidler)

• Calculations regarding the back-scattering of different Wide Angle Baffle designs (Zeidler)

• Personal calc of WAB's stray light noise by Akutsu; due to several uncertain parameters there are several results and no one would know the actual effect!

• Heat links positions (by Obuchi) fmkopgehpapgdkcc.png

Task list

• Place/install the WAB suspension.
• Measure several relative dimensions to get useful information for the future commissioning; concretely speaking:
  • What....?

• Test the saving mode of the WAB suspension.

• Don't forget to replace the damping magnets to SmCo ones.

  • What is the requirement to say the damping is sufficient...?
• Connect electric cables (with checking) in the IYC chamber.

  • 3 photosensors; in each photosensor head, two PDs should be connected parallel. Need to calibrate the response of each sensor head...

  • 2 heaters; should be connected parallel??
  • 1 coil for actuation.

  • 6 thermometers with (extended?) patch cables made of phospher bronze; the extended double twisted pare cables will be delivered on Jan 26

• Connect 4 heat links.
• Check oplev signals.
• Connect cables the outside as well.
• Make a realtime model to monitor.
• Take interface with Tcam.
• Make a plan to do leak check before cooling down.
• Don't forget to add some heat links (Cu?) to the top of the suspension...

Photosensor

The PDs and LED are aligned as shown in the below picture.

PIN Assign

• Summary of the pin assign of burndy connector inside the cryostat.

NOTE: The meaning of color for thermometer cable is
RED = I- , YELLOW = I+ , GREEN = V- , BLACK = V+

P22

P23

DAQ

Real-time computer: k1???

OpLev

• Optical lever installed at the +X/-Y side of the IYC
• Path-length inside the chamber (viewport to viewport): ~3000 mm

WAB Alignment

• Alignment done with 2 laser-leveler inside the IYC
• Regarding the used terms:
  • As the baffle is placed along the Y-arm, +Y and -Y refer to both long ends of the baffle toward the Y-end and toward the center area, respectively!
  • The same holds true for the horizontal dimension in x-arm direction (+X means toward X-end and -X toward center/PSL)

Yaw

• laser-leveler needs to be close to the -Y main-beam entrance in a height 300 - 400 mm above the optical table
• Vertical laser line to be adjusted to the main-beam indication on the optical table and the inner wall of the cryostat
• Checked the line by using the slids of the flanges on top the WAB (each slid is ~3.5 mm broad)
• For both slids, the laser line is mismatched (not centered) toward -X by ~0.5 mm (@ +Y slid) and ~1 mm (@ -Y slid)

That means that there is probably also a -X offset!

• The flanges have a distance of 170 mm which indicates a maximum yaw-tilting of ~0.1 degrees

Note: taking the distances is very hard as the position of the slids is not easy to access

Pitch

• laser-leveler outside the cryostat (but inside IYC) set to give a horizontal line along length side of the baffle

• Found a slight mismatch for the outer screw holding the OpLev mirrors in +Y,+X and -Y,+X

• Difference is ~1 mm (+Z @ -Y, so -Y-side is higher than +Y-side)
• With approx. 500 mm distance between both screws, the maximum pitch is ~0.1 degrees

Roll

• Took the height of the OpLev mirror screw-holes (@ -Y,+X and -Y,-X) with a vertical ruler and the horizontal line of the laser-leveler outside the cryostat

• Measured a difference of 2.5 mm which makes it a roll of 0.55 degrees (radius of baffle ~130 mm); -Y,-X is higher!
• Then took the height of baffle-wings which are mounted on the flanges and could not measure any difference (within an error of 0.5 mm)
• Hence, only the baffle is slightly rolled within the flanges!