In an article written by Fermilab's Maxwell Bernstein, Dr Chris Densham, our High Power Targets Group Leader, explains how his team developed a 1.5 metre long graphite target for the Long Baseline Neutrino Facility's Deep Underground Neutrino Experiment.
A computer simulation of helium coolant flowing through the LBNF target developed by Chris and his team."About every second, a high-intensity pulse of protons will hit the target for the LBNF/DUNE experiment, and billions of neutrinos will be produced,” said Chris Densham, the high-power targets group leader at Rutherford Appleton Laboratory in Oxfordshire, England.
“You create a very short pulse so that your detectors can know when the particles came from Fermilab.”
For LBNF, Densham is leading Rutherford Appleton’s contribution to create the target. The graphite target for LBNF/DUNE will be 1 1/2 meters long and will operate at a high temperature, allowing the material to partially repair itself as it is being irradiated.
“Graphite is a strange material; it’s quite happy being hot,” said Densham. “When it gets hot, it causes the structure to jumble around. If there’s an atom that gets knocked out of place, there is another one that’s able to fill it in.”
Due to the thermal shock that will be produced by quick pulses, Densham and his team developed a unique temperature control system to help equalize the temperatures within the target and the target surface which can help increase the lifespan of the target.
“We are going to use gaseous helium flowing over at high velocity around 440 meters per second,” said Densham. (Essentially, the helium could travel around a school’s running track in a second). “The end of the target looks like the front of a jet engine. Helium is a gentle coolant that doesn’t take too much heat out, so the target runs hot.”
“There’s a surprising amount of engineering details in making these targets and integrating them together,” added Densham.
View the full article on
Fermilab's website.
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