thomas.shaffer@LIGO.ORG - posted 16:31, Thursday 04 June 2026 - last comment - 15:57, Friday 05 June 2026(90493)
HAM2 SPI ISIJ and below table
When I hammered the below table "beard" baffle on May 26 (alog90335), something wasn't correct with the way I saved the data or my configuration or something else. Either way, Jeff and went in today and hit that as well as the SPI ISIJ assembly with and without the cylindrical shroud (D2500030). Preliminary results are looking much better, so I'll clean those up and post them soon with a whole writeup.
J Kissel, T Shaffer
All plots are in the accelerometer axis as defined below for each test. The measurement numbers were just for my own organization within the B&K software.
ISIJ
We did this in two stages, one set with the D2500030 cylindrical shroud and one set without. The accelerometer was mounted on a bolt hole below the ISIJ on the HAM face (photo).
The shroud has clear resonant peaks at 137, 196, 314Hz. It was ultimately decided to leave this piece off for now.
Below Table Baffle
Measuring the central below table baffle (D2600042) with the accelerometer mounted on the L bracket (D1700264) on the outermost bolt hole (photo). The accelerometer axis X,Y,Z = IFO -Z,Y,X.
Meas 1 - First hit IFO +X (+Z acc) bottom of L bracket - attachment 4
Meas 2 - hit in -Y IFO (-Y acc) on L bracket - attachment 5
Meas 3 - hit in +Z IFO (-X acc) L bracket bottom. Note that the bracket is tilted in the IFO -X direction. - attachment 6
There is a small peak at 87Hz.