The INS Capabilities

1. Fast Neutrons INS Gammas Prompt Gammas * Delayed  H, N, Si, S, Ca, P C, O, Si, Mg Prompt  Cc(x,y,z) Particle  γ n 75sec 25sec z z z z z 0 ~ 500 μsec Neutron Thermalization via Elastic Scatterings and Thermal Neutron Capture Shielding Detectors Shielding Neutron Generator H2O Al 30 cm Delayed Gammas Na, Cl, Ca, Al, K (n,n’γ) Interaction Site Soil ~ 0.001 to ∞ sec Delayed Activation Following Neutron Capture φn(x,y,z,E) Atc(x,y,z) Ω(x,y,z) ρb(x,y,z) Surfaces describing the volumes from which a 90, 95 and 99% of the carbon gamma rays signal intercepts the detectors. Carbon Profile Neutron Profile Signal Attenuation Solid Angle Bulk Density INS Alpha prototype for field measurements Inelastic Neutron Scattering, INS, A Novel Non-Destructive Soil Carbon Analysis System; I - Principles L. Wielopolski, S. Mitra, O. Doron 1Brookhaven National Laboratory, Environmental Sciences Department Upton, NY 11973 lwielo@bnl.gov Principle: INS is based on spectroscopy of gamma rays induced by nuclear interaction of fast neutrons with elements present in the soil matrix. The fast 14 MeV neutrons are produced by a pulsed neutron generator that induce 4.44 MeV carbon gamma rays detected by an array of NaI detectors. Neutron Interactions With Matter Activation (n) + zAn+z zAn+z+1 (n, ) (n,x, ) ,n’,  ,2n, ,p, ,,,  Elements measured in situ: H, N, C, O, Na, Cl, Si, Ca, Fe, Ti, Gd, S, Al, K, U, Th Gamma ray spectra following neutron inelastic scattering (on the left) and thermal neutron capture (on the right) showing carbon and nitrogen peaks respectively. These spectra are acquired concurrently into two separate memory bins. INS System Response Function; Solved using Monte Carlo method CN = k∫dt ∫ ∫∫∫φn(x,y,z,E)σ(E)Cc(x,y,z)ρb(x,y,z)Ω(x,y,z)· At(x,y,z)Det(x,y,z)dEdxdydz T E V CN in units of [C net counts/(gC/cm2)/sec/n] • The INS Capabilities • Due to nuclear interactions the INS system measures specifically elemental carbon independent of chemistry. • The system sees constant volume, about 0.3 m3. • The INS signal is linear with carbon abundance in a given volume. • Due to very fast interaction times the system can be used in a stationary or continuous scanning modes at approximates speed of 10 km/h. • INS provides multielemental quantitative analysis for C, N, K, P, and others elements. • It is rapid, in situ, and non-destructive thus enabling true sequential measurements. • Can be adapted for non-destructive carbon depth profiling or monitoring carbon changes in a given depth interval.