Building a Neutron Veto for Dark Matter Detection

Dark matter is a hypothetical form of matter that is believed to make around 85% of the universe's total matter. There have been many experiments trying to detect dark matter, but so far there has been only indirect evidence of its existence. Direct detection of dark matter remains one of the most important challenges of twenty-first-century physics.

The neutron veto detector needed by the COLa collaboration will need to (1) fully enclose the experiment, (2) be able to support the gadolinium-loaded scintillators, and (3) have openings for cables and heat to come out of the dark matter detector. The support structure of a solid-scintillator neutron veto satisfying those requirements has not been devised yet. Under the guidance of my mentor, Dr. Rafael de la Madrid, I designed a prototype for the support structure of a neutron veto that fulfills those requirements. This support structure will be useful not just for the DRIFT@MESA detector, but also for another dark matter experiment called DarkMESA, also to be deployed at the MAMI accelerator in Mainz, Germany.

Through the support of the SURF grant at Lamar University, my mentor and I worked on the design of the support structure of the neutron veto. Initially, we built a 4”x4” embryo of the support structure with balsa wood to prove the feasibility of our design. Once we saw the design was feasible, we built a prototype of the support structure of the neutron veto. The support structure is a series of nested cubes supported by aluminum extrusion. Instead of the (expensive) plastic scintillators, we used (cheap) wood blocks. The resulting support structure fulfills the requirements (1)-(2) mentioned above, but not requirement (3). To fulfill the requirement (3), we have designed an additional support structure that will allow heat and cables to come out of the inside of the cubes, and to support fans for cooling.