In many theoretical frameworks our visible world is a 3D sheet (a 3-brane) embedded in a multidimensional space-time (the bulk), possibly coexisting with hidden braneworlds. It is then a major concern to constrain these scenarios, which are at the heart of many scenarios of physics beyond the standard model of particle physics or beyond the cosmological ΛCDM model. Hidden 3-branes can be constrained as matter exchange between braneworlds must occur.
In the context of the MURMUR collaboration, the present PhD project will lead to develop and to carry out a neutron passing-through-wall experiment.
Hidden neutrons can be generated in the moderator medium of a nuclear research reactor (here the BR2 at the SCK・CEN), where a high flux of neutrons undergoes many elastic collisions. Being located in another braneworld, these hidden neutrons would interact very weakly with matter and freely escape the reactor out of the biological shielding. However, the reverse swapping process would permit to detect them close to the reactor thanks to a material able to regenerate hidden neutrons into visible ones.
The main part of the present project will consist to develop the ultra-low noise neutron detector, which would allow detecting reappearing neutrons to constrain the physics behind. For that purpose, the design of a convenient shielding and of the low-noise neutron detection chain, as well as the required numerical simulations will be necessary.
The device and the related detection chain could be used for future applications in radioisotope tracking for security purposes for instance.