Neutron spectroscopy with a spherical proportional counter for precision measurements in deep-underground laboratories
The concept of neutron spectroscopy dates back to neutron discovery in 1932. Despite several attempts towards an efficient neutron spectroscopy system, such measurements remain cumbersome and detailed neutron spectra are sparse both in scientific laboratories and industrial sites. To-date the most widely used method relies on the 3He(n,p)3H reaction, which - however - is more well suited for thermal neutrons and is particularly expensive, given that 3He is scarce. All existing alternatives are plagued by major disadvantages: toxic/corrosive gases, poor efficiency, limited radiation hardness, degraded energy resolution. 
The neutronSPHERE project will provide a unique alternative to 3He-based detectors for neutron spectroscopy by using the Spherical Proportional Counter (SPC), a high-gain large-volume gaseous detector, filled with a nitrogen-based mixture. The detection principle exploits the 14 N(n, α )B11 and 14 N(n, p)C14 processes, and exhibits all major advantages of 3He-based detectors, and goes beyond that to provide fast neutron spectroscopy at an affordable price. This breakthrough is enabled by novel developments in SPC instrumentation that the host has played a key role in demonstrating. 
The capabilities of the developed neutron spectroscopy system will be demonstrated in two application: Firstly, neutronSPHERE will provide the first high precision measurements of the neutron background spectrum in underground facilities. These will provide a unique insight and will immediately inform direct searches for Dark Matter. Then, neutronSPHERE will measure in situ the neutron-induced dose during proton therapy treatments, which is a crucial element in hadron therapy treatment and planning.