Reports until 08:38, Tuesday 30 June 2026
H1 SQZ
camilla.compton@LIGO.ORG - posted 08:38, Tuesday 30 June 2026 - last comment - 13:32, Tuesday 30 June 2026(90815)
M^2 Measurements in SQZT7 of Beam Upstream of ZM4

Ryan S, Camilla, Sheila 

We put a temporary steering mirror into HAM7, upstream of ZM4 sending the beam out to SQZT7 to try to measure the M^2 and beam astigmatism before ZM4. Location of mirror attached. Repeated with different ZM2 PSAMs values. 

The M^2 data is attached but seemed debatable, with high with M^2 values: > 1.5 when we expect <1.2 to align with 90783. Maybe as the beam was large at the Thorlabs M^2 head, but it was smaller than specs, ~5mm diameter when max was 9mm diameter. 

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Jun29_2026.zip
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camilla.compton@LIGO.ORG - 13:00, Tuesday 30 June 2026 (90827)
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This morning Ryan and I moved the steering mirror to downstream of ZM4 and repeated these measurements, with different ZM4 PSAMs values and then with ZM4 PSAMs back to nominal and a few different ZM2 PSAMS settings. Data attached.

Yesterday we moved the flipper mirror picking off the beam into the M^2 2" off the nominal path, today we moved it back to be in the nominal Homodyne/IR PD path. 

  • Steering mirror to ZM4 = 395mm
  • Steering mirror to beam diverter = 150mm
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