Tag Archives: cables

Cable Installation in the Cryogenic Pipe

The XENON1T detector sits in the center of a large water tank. All the signal and high voltage cables for the photosensors in the time projection chamber are guided by a pipe that goes from outside where the computers are located—through the tank to the detector. This stainless steel pipe was produced by ALCA, a company located near Vicenza in Italy.

More than 900 cables, each 10 meter long, had to be inserted into a 10 centimeter diameter pipe. Before the installation the cables were prepared at the University of Zurich. We developed two types of connector made out of PTFE and copper; one for the high voltage cables, one for the signal cables. These connectors satisfy the stringent requirement on radioactive cleanliness. Each holds 24 cables into one bunch. These connectors were mounted on both sides such that they can be easily connected to the detector itself inside the water tank and to other cables, leading to the electronics outside of the water tank. After bunching the cables they had to be cleaned and packed carefully to protect them from pollution during the transportation to ALCA.

Custom made HV connector with Kapton single wires

Custom made HV connector with Kapton single wires

At ALCA, each bunch was unpacked and one after the other inserted into the pipe for which we fixed each to a steal pulling wire. After all bunches were successfully inserted, both ends of the pipe were closed with caps, because the pipe had to be pumped in order to remove substances like water or alcohol that remained in the cable bunches from the cleaning process.

Installation of the signal cables under clean conditions.

Installation of the signal cables under clean conditions.

Cryogenic Pipe Installed

The XENON1T detector sits in the center of a large water tank. All the signal and high voltage cables, pipes for liquid and gaseous xenon, vacuum piping and various other lines get there via one large pipe.

Installation of the cryogenic pipe inside the XENON1T water tank, July 2014

Installation of the cryogenic pipe inside the XENON1T water tank, July 2014

We have just finished the installation of this pipe. It’s actually a quite fascinating piece of engineering. In it, there are all the signal and high voltage cables for the photomultiplier tubes. There are pipes to recirculate the xenon for purification in the adjacent building, which are themselves inside a vacuum-insulated pipe that in turn runs inside this pipe. The large diameter pipe is also used to evacuate the cryostat, as well as the heat insulation of the cryostat. And it holds a bunch of extra cables and wires for various other sensors. So, it’s really much more than just a pipe. It’s the lifeline to the detector. And it’s pretty cramped:

Cable bunches

These are the signal wires, bunched together into a single pipe inside the cryogenic pipe. They are PTFE-insulated, low-radioactivity wires with custom-made connectors.