The Search for Dark Matter – DEAP 3600 – Bonding
The DEAP-3600 experiment will soon start it’s search for Dark Matter using 3.6 tonnes of liquid argon. One thing that many people don’t realize is that the design and construction of various scientific equipment and apparatus is often extremely challenging, and results in something that during its construction, looks extremely beautiful.
DEAP-3600 is no exception. The inner heart of the detector is a 85cm radius acrylic sphere, this is surrounded by cylindrical acrylic light guides. Now, mixing units up, the Acrylic vessel was fabricated using bonded panels which where cut and thermal formed into orange peal gores. These gores where then bonded together to form a sphere.
Simple right? Well not really. Once bonded into a sphere (with the top of the sphere cut off for transport reasons) the acrylic was first machined at the University of Alberta, which took the vessel from a smooth sphere into a sphere with 8 inch diameter circular stubs. The whole thing, along with a cap to finish the top of the sphere, along with a neck section too where then shipped to Sudbury ontario, where it travelled underground to the SNOLAB facility.
After this, a whole process was undertaken to bond on the top, the neck and then a total of 255 20 inch long, 8 inch wide light guides. All from acrylic. This process was extremely challenging and as the vessel took form, it looked increasingly pretty to look at.
Now in its final resting place, last year I took the opportunity to take some photographs of the Vessel during the process of ‘dressing’ That is, covering all that acrylic with components for the detector. This includes reflective films, insulation, light tightening, neutron shielding, temperature sensors and optical sensors. It was an extremely difficult and involving process. One of which I was not largely involved with, my tasks being elsewhere in the experiment. So I will present a series of posts with a small selection of photographs of the DEAP acrylic vessel for all of you to enjoy.
Very yellow picture due to the cream painted walls and the florescent lighting. Tried to neutralize it best i could. Here you see DEAP, early in its construction, during the initial light guide bonding stage, mounted on a rotator frame. This is really the first photograph I personally have of the acrylic vessel on film. Framing is not so good as I am a little too close, BUT I couldn’t stand any further back due to other activities in the lab that day.