Numerische und experimentelle Untersuchungen zur Beschreibung der Wirkungsweise und Effektivität von grossflächigen hochsensitiven SPNDs : Self-Powered-Neutron-Detectors

In the present work the neutron sensitivity of large surface "Self-Powered- Neutron-Detectors«SPNDs) is determined numericaily and experimentally. First a computer model for the parametric caIculation of the (n,$\gamma$)-reaction rates in the emitter of the SPND was developed under use of the Monte-Carlo-Program KENO 11 ‘To determine the escape-probability of the electrons produced via Comptonor photoelectric effect by the emitter as weil as fron the surrounding isolator, a new Monte-Carlo-Program was implemented under consideration of the Klein-Nishinaeformula and the energy-range relationships for electrons. The approximate calculations performed for the electrons produced in the isolator show that the "isolator flux" can give an important contribution to the total signal of the SPND.Subsequently with this program System an optimization of the neutron sensitivity was performed by a suitable choice of geometry (emitter thickness, isolator thickness). For a specially bunt large surface SPND with Gadolinium-emitter the neutron sensitivity was calculated. These resuits were checked by an In-Pile-experiment in the FM-1 reactor. Very good agreement was found. The detector was also shown to exhibit excellent linearity and showed also the expected enhanced sensitivity