2. Looking for the best possible geometry for NEDA  Optimization of the volume of the detectors  Highest efficiency  Lowest cross-talk probability Granularity Modularity Different materials We took into account:

3. Definitions: The Cluster method Each pair of detectors is checked whether they fit to the drdt gate. If one detector is recognized as having the scattered event from the current cluster is added to that cluster. The number of cluster gives the number of neutrons detected. The drdt gate dr is the distance between the weight centers of two fired detectors. dt is the time difference between the moments of threshold exceedance of each detector, separately.

4. Definitions: Efficiency Clean 1n and 2n efficiency is the number of clusters which fit to drdt gate, in case the emitted neutron multiplicity is one and two, respectively. 1n -> 2n misinterpretation probability is the probability to treat 1n events as 2n. It means that is the ratio of the number of clusters which do not fit to the drdt gate to the total number of neutrons were shot.

5. Definitions: The drdt gate An example for the drdt gate (Staircase geometry):

6. Definitions: The neutron source: Neutron were shot in energies sampled from a 252 Cf source. (see plot) Threshold: 50 keV ee threshold has been considered for the light output

7. FlatZigzag 1 mDistance from the source1 m 169Granularity169 507 l Total Volume 507 l 3 l Unit Volume 3 l 1n Eff. BC501A9.08 %7.33 %BC501A BC5376.89 %5.82 %BC537 0.60 πSolid Angle Coverage0.60 π

8. Staircase 1πStaircase 2π 1n Eff. BC501A15.97 %31 %BC501A BC53712.05 %24 %BC537 1 mDistance from the source1 m 163Granularity355 489 l Total Volume 1065 l 3 l Unit Volume 3 l 1 πSolid Angle Coverage2 π

9. Spherical N180The Neutron Wall 0.50 mDistance from the source0.51 m 45Granularity50 202.5 l Total Volume 150 l 4.5 l Unit Volume 3 l 1n Eff. BC501A15.57 %15 %BC501A BC53712.66 %N/ABC537 1 πSolid Angle Coverage2 π

10. Spherical 1πSpherical 2π 1 mDistance from the source1 m 326Granularity606 652 l Total Volume 1212 l 2 l Unit Volume 2 l 1n Eff. BC501A19.25 %37 %BC501A BC53715.27 %29.35 %BC537 1 πSolid Angle Coverage1 π

11. Distance /radius Granularity Total Volume (L) Cell Volume (L) Solid Angle (π) Material Efficiency (1n) Flat1 m16950730.6 BC501A9.90 % BC5376.89 % Zigzag1 m16950730.6 BC501A7.33 % BC5375.82 % Stairs 1π1 m16348931 BC501A15.54 % BC53712.05 % Stairs 2π1 m35510653~2 BC501A31 % BC53724 % Spherical N180 0.5 m45202.54.51 BC501A15.57 % BC53712.66 % Sperhical 1π1 m32665221 BC501A19.25 % BC53715.27 % Sperhical 2π1 m606121222 BC501A37 % BC53729.35 % NWall0.51 m50150~31 BC501A15 % BC537N/A