At about 2:00AM in Chooz, France, a dedicated group of physicists finished filling the Double Chooz far detector with the neutrino detecting liquid scintillator. The filling procedures were carefully executed over the last two months and everyone is very excited to be past this stage. As a quick reminder, the Double Chooz detectors are concentric cylinders made of acrylic. Each tank is filled with a different kind of liquid, and so special care needs to be taken in order to ensure that each tank is filled simultaneously. Even a small difference in the liquid levels could put enough pressure on the acrylic cylinders to crack them.
Special thanks is owed to our filling team on site, and to those collaborators who helped monitor the detector remotely while our filling team slept.
There are many more installations needed for the detector to be fully functional, but this is an exciting step forward!