90 likes | 260 Views
Interaction of Energy and Matter: Dawn Mission Instrumentation. GRaND Gamma Ray and Neutron Detector. What is GRaND?. GRaND is a. Gamma Ray Spectrometer. and. Neutron Detector. What will GRaND do?. GRaND will measure the abundances of.
E N D
Interaction of Energy and Matter:Dawn Mission Instrumentation GRaND Gamma Ray and Neutron Detector
What is GRaND? GRaND is a Gamma Ray Spectrometer and Neutron Detector
What will GRaND do? GRaND will measure the abundances of • major rock-forming elements—O, Mg, Al, Si, Ca, Ti, and Fe • long-lived radioactive elements—K, Th, and U • volatiles—H, C, N, and O—major constituents of ices
Cut-away view of Dawn Spacecraft’s GRaND Gamma Ray Spectrometer 4 x 4 array of CdZnTe crystal detector • narrow range (0-3 Mev) • more accurate in low energy regions • measures rays from radioactive elements like K, Th, and U 10 kg 26 cm Wide range, high-efficiency BGO crystal detector can detect rays from H, O, Mg, Si, Ca, Ti, Fe 25.7 cm 18 cm
Cut-away view of Dawn Spacecraft’s GRaND Neutron Detectors Borated plastic scintillators interact with epithermal and fastneutrons releasing gamma rays CdZnTe crystal detector 6Li-loaded glass scintillators interact with thermal neutrons produce gamma rays BGO crystal detector Leaking neutrons produce gamma rays that can detect the presence of H, C, N, O, Fe, Ti, Cl, Gd, and Sm
Interactions of Energy and Matter What Energy and Matter Interactions are involved in the scientific measurements made by GRaND?