Speaker
Description
Neutron detection sometimes plays a vital role in direct studies of astrophysically important reactions. In particular, the reaction 22Ne(a,n)25Mg is undergoing study using the SHADES array at the Belotti Ion Beam facility at Laboratori Nazionali del Gran Sasso. This reaction, and 13C(a,n)16O, is widely regarded to serve as a neutron fuel for the slow neutron capture (s-) process occurring in massive stars and asymptotic giant branch stars, which synthesise elements above A = 60 – 90 and 90 – 209, respectively. Prior to constructing the full SHADES array, the neutron detection capabilities of its detectors were tested using a scaled-down prototype array and a neutron beam produced at the Goethe University Frankfurt’s Van de Graaf accelerator facility “FRANZ”. The prototype consisted of an EJ-309 liquid scintillator surrounded by six 3He proportional counters. Under study was the neutron / gamma-ray discrimination performance of the EJ-309 using traditional and machine-learning techniques, the lower detection limit of the neutron energy, and the timing coincidence features between the EJ-309 and counters. In future, such coincidence is expected to improve the sensitivity of the full SHADES array via a novel anti-coincidence gate on background neutrons. This talk will summarise the measurement performed at Frankfurt and the determined characteristics of the prototype array.
