Jorge Pullin

Raising the clean room that sits on the Beam Splitter Chamber (BSC2), now that it is installed. It had been lowered for installation. Each leg has an actuator (that yellow thing behind the curtain) and is controlled by the box visible in front. @LIGOLA

Anamaria Effler and Gabriela González make empanadasaurs for the end of semester party of Gaby's LIGO group. @LIGOLA

Using the autolevel on the keel of the active isolation system (ISI) that holds the Bigger Beam Splitter @LIGOLA

From my friend Hugo Fort, routledge.com/Modelling-Prac…

The optical sensor electromagnetic actuators for the Bigger Beam Splitter are known as qosems. Because they were built in Australia, the electronic chassis that takes their readout bears a koala. @LIGOLA

The online seminar I have been running every two weeks for the last 20 years (yes, I was running an online seminar in 2006!) will now become the official seminars of the International Society on Loop Quantum Gravity. They gave me a plaque to mark the event. I am very grateful to everyone that has made the seminars possible.

"The flight" of the Bigger Beam Splitter into its final position in the vertex of the interferometer. It is the first time in history an advanced interferometer had its beam splitter replaced. The Director of LIGO said "That's small step for BBS, one giant leap for LIGO." @LIGOLA (Video credit: Michael F and Kwentin R).

ligo.caltech.edu/news/ligo20260… LIGO India Breaks Ground.

Final alignment of the Bigger Beam Splitter. We got it to 1 arc second of spec in pitch and 10 seconds in yaw. Tomorrow looks like it is going to be the big day! After two years of building it, the BBS will take its "flight" (that is what they call it) into the interferometer. @LIGOLA

Inspecting the optic of the Bigger Beam Splitter. (I was mostly just holding the light later to get a better picture of potential imperfections). @LIGOLA

In order to insert the optic usign the ErgoArm, we had to place the Bigger Beam Splitter facing the opening between the legs of the "white elephant" it is mounted on. But that is not the correct orientation. So we had to rotate it. The Alum-a-Lift cannot easily maneuver there either so we inserted teflon strips (green arrow) that allowed us to do the final adjustments by hand. @LIGOLA

Completed my harness training. @LIGOLA

Picking up and installing the optic in the Bigger Beam Splitter using the "ErgoArm". @LIGOLA

Building dampers for the double suspensions. They are an enclosure with a metal cube inside held in place by o-rings. It behaves like a "mass and spring" system that damps vibrations in the structures it is attached to. @LIGOLA

We rearranged the trim masses on the active seismic isolation system (ISI) to take into account the weight distribution of the new bigger beam splitter that is hanging from it. It was exhausting work, the masses are heavy and one is working overhead. @LIGOLA

Centering the HEPI (hydraulic external pre-isolator; the passive seismic isolation system) for the new beam splitter. One uses the adjustment screws (green arrow) and follows progress in the x, y, z axes using three micrometers (red arrow). @LIGOLA

The LIGO electric guitar goes golden. The new beam splitter mirror is suspended by gold plated wires. As usual, we pre-tensioned them by strumming them as a guitar and measuring the frequency. We do it with an actual electric guitar pickup hooked up to an oscilloscope. @LIGOLA