Weerg Helps Physicists Track the Mysterious Neutrino with 3D Printing

3D printing service Weerg is manufacturing parts for the KM3NeT, an undersea research installation that will help scientists learn about the mysteries of the neutrino particle.

KM3NeT is a collaborative project helmed by Nikhef, the Dutch National Institute for Subatomic Physics. The project’s goal is to create a net of thousands of optical sensors at three sites in the Mediterranean Sea, all of them observing the behavior of neutrino particles and tracking the large cosmic bodies they come from. While parts of this “net” have been rolled out, its final form will stretch over 1 cubic kilometer of ocean.

The individual units of this net are digital optical modules (DOMs), or glass spheres filled with measuring equipment. Each DOM is studded with 31 photomultipliers to record the light coming through the water, and will carry a set of positional equipment to tell the researchers where each reading is coming from. The researchers can put together the information from multiple sensors to track the progress of neutrino particles through the water, and have also been able to make some surprising discoveries about bioluminescent sea life.

A single sensor module, cut open to see the photomultipliers (Image via KM3NeT).

Italian printing company Weerg will be making an important part of these DOMs: a set of 380 mm (14.9 inch) half-spheres made from Nylon PA12. The material was chosen for its limited water absorption, chemical resistance, and rigidity. The last property is particularly important, as the DOMs will be up to 3500 m below sea level, and function under a water pressure of 350 times normal atmospheric pressure.

These half-spheres are being printed on the HP Multi Jet Fusion 5210, an industrial material jetting printer released in 2019.  Weerg’s installation of the 5210s is the largest such installation in Europe.

A visualization of what a KM3NeT site might look like once completed (Image via Edward Berbee/Nikhef)

Nikhef was particularly interested in Weerg because of these 5210s. The organization had early difficulties finding cost-effective and high quality parts.

“We have been working on this project since 2013 and over the years we have contacted about 50 different suppliers,” said Nikhef mechanics coordinator Edward Berbee. Faced with these problems, they initially considered buying their own set of 5210 printers. “While we were considering whether or not a research institution like ours should purchase the system, we read an article announcing Weerg’s record-breaking installation of HP 3D printers”.

So far, Weerg has printed about 300 of the half-spheres, along with various other parts that Nikhef has requested.