caa a22 4500 445816279 CHVBK 20180317145229.0 cr unu---uuuuu 170323e20111201xx s 000 0 eng 10.1007/s11214-011-9862-0 doi (NATIONALLICENCE)springer-10.1007/s11214-011-9862-0 Dawn's Gamma Ray and Neutron Detector [Elektronische Daten] [Thomas Prettyman, William Feldman, Harry McSween Jr., Robert Dingler, Donald Enemark, Douglas Patrick, Steven Storms, John Hendricks, Jeffery Morgenthaler, Karly Pitman, Robert Reedy] The NASA Dawn Mission will determine the surface composition of 4 Vesta and 1 Ceres, providing constraints on their formation and thermal evolution. The payload includes a Gamma Ray and Neutron Detector (GRaND), which will map the surface elemental composition at regional spatial scales. Target elements include the constituents of silicate and oxide minerals, ices, and the products of volcanic exhalation and aqueous alteration. At Vesta, GRaND will map the mixing ratio of end-members of the howardite, diogenite, and eucrite (HED) meteorites, determine relative proportions of plagioclase and mafic minerals, and search for compositions not well sampled by the meteorite collection. The large south polar impact basin may provide an opportunity to determine the composition of Vesta's mantle and lower crust. At Ceres, GRaND will provide chemical information needed to test different models of Ceres' origin and thermal and aqueous evolution. GRaND is also sensitive to hydrogen layering and can determine the equivalent H2O/OH content of near-surface hydrous minerals as well as the depth and water abundance of an ice table, which may provide information about the state of water in the interior of Ceres. Here, we document the design and performance of GRaND with sufficient detail to interpret flight data archived in the Planetary Data System, including two new sensor designs: an array of CdZnTe semiconductors for gamma ray spectroscopy, and a loaded-plastic phosphor sandwich for neutron spectroscopy. An overview of operations and a description of data acquired from launch up to Vesta approach is provided, including annealing of the CdZnTe sensors to remove radiation damage accrued during cruise. The instrument is calibrated using data acquired on the ground and in flight during a close flyby of Mars. Results of Mars flyby show that GRaND has ample sensitivity to meet science objectives at Vesta and Ceres. Strategies for data analysis are described and prospective results for Vesta are presented for different operational scenarios and compositional models. Springer Science+Business Media B.V., 2011 Dawn mission nationallicence Asteroid nationallicence Vesta nationallicence Ceres nationallicence Geochemistry nationallicence Gamma ray nationallicence Neutron nationallicence Spectroscopy nationallicence ADC : Analog to Digital Converter nationallicence AMP : Linear amplifier nationallicence ATLO : Assembly, Test, and Launch Operations nationallicence BLP : Boron-Loaded Plastic nationallicence BGO : Bismuth Germanate nationallicence CAT : Category nationallicence CMA : Central Moving Average nationallicence CPG : Coplanar Grids nationallicence CZT : Cadmium Zinc Telluride nationallicence DLR : Differential Line Receiver nationallicence DN : Data Number nationallicence DTS : Decimated Time Series nationallicence EDR : Experimental Data Record nationallicence EMC : Electromagnetic conductance or Earth-Mars Cruise nationallicence EMI : Electromagnetic interference nationallicence EOP : End of Process nationallicence FEE : Front End Electronics nationallicence FEIR : Full Energy Interaction Rate nationallicence FET : Field Effect Transistor nationallicence FPGA : Field Programmable Gate Array nationallicence FWHM : Full Width at Half Maximum nationallicence GI : Gated Integrator nationallicence GPAW : GRaND Peak Analysis Widget nationallicence GRaND : Gamma Ray and Neutron Detector nationallicence HED : Howardite, Eucrite, and Diogenite nationallicence HV : High Voltage nationallicence HVPS : High Voltage Power Supply nationallicence ICO : Initial Check Out nationallicence INV : Signal invert nationallicence LAMO : Low Altitude Mapping Orbit nationallicence LIG : Lithium-loaded Glass nationallicence LLD : Lower Level Discriminator nationallicence LPF : Low Pass Filter nationallicence LVPS : Low Voltage Power Supply nationallicence MCA : Mars Closest Approach nationallicence MCNPX : Monte Carlo N-Particle eXtended nationallicence MGA : Mars Gravity Assist nationallicence MUX : Multiplexor nationallicence MVC : Mars-Vesta Cruise nationallicence NIPC : Non-Interactive Payload Command nationallicence PDS : Planetary Data System nationallicence PMT : Photomultiplier tube nationallicence QSP : Charge-sensitive preamplifier nationallicence RDR : Reduced Data Record nationallicence REE : Rare Earth Elements nationallicence RMS : Root Mean Square nationallicence S/C : Spacecraft nationallicence SCET/UTC : Spacecraft Event Time/Universal Time Coordinated nationallicence SEP : Solar Energetic Particle nationallicence SIS : Software Interface Specification nationallicence SOH : State of Health nationallicence SPICE : System of applications and data maintained by NASA's Navigation and Ancilliary Information Facility (Acton 1996) nationallicence SSD : Scintillator Shaper-Digitizer nationallicence TG : Threshold Generator nationallicence TTSP : Time to Second Pulse nationallicence TVACQ : Thermal cycling in Vacuum for instrument Qualification nationallicence UART : Universal Asynchronous Receiver/Transmitter nationallicence VIR : Visible and Infrared nationallicence VR : Virtual Recorder nationallicence WEH : Water-Equivalent Hydrogen nationallicence ZCD : Zero-Crossing Discriminator nationallicence Prettyman Thomas Planetary Science Institute, 85719, Tucson, AZ, USA aut Feldman William Planetary Science Institute, 85719, Tucson, AZ, USA aut McSween Jr. Harry University of Tennessee, Knoxville, TN, USA aut Dingler Robert Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut Enemark Donald Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut Patrick Douglas Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut Storms Steven Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut Hendricks John TechSource, Inc., 87544, Los Alamos, NM, USA aut Morgenthaler Jeffery Planetary Science Institute, 85719, Tucson, AZ, USA aut Pitman Karly Planetary Science Institute, 85719, Tucson, AZ, USA aut Reedy Robert Planetary Science Institute, 85719, Tucson, AZ, USA aut Space Science Reviews Springer Netherlands 163/1-4(2011-12-01), 371-459 0038-6308 163:1-4<371 2011 163 11214 https://doi.org/10.1007/s11214-011-9862-0 text/html Onlinezugriff via DOI 1 review-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11214-011-9862-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Prettyman Thomas Planetary Science Institute, 85719, Tucson, AZ, USA aut NATIONALLICENCE 700 1- Feldman William Planetary Science Institute, 85719, Tucson, AZ, USA aut NATIONALLICENCE 700 1- McSween Jr Harry University of Tennessee, Knoxville, TN, USA aut NATIONALLICENCE 700 1- Dingler Robert Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut NATIONALLICENCE 700 1- Enemark Donald Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut NATIONALLICENCE 700 1- Patrick Douglas Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut NATIONALLICENCE 700 1- Storms Steven Los Alamos National Laboratory, 87545, Los Alamos, NM, USA aut NATIONALLICENCE 700 1- Hendricks John TechSource, Inc., 87544, Los Alamos, NM, USA aut NATIONALLICENCE 700 1- Morgenthaler Jeffery Planetary Science Institute, 85719, Tucson, AZ, USA aut NATIONALLICENCE 700 1- Pitman Karly Planetary Science Institute, 85719, Tucson, AZ, USA aut NATIONALLICENCE 700 1- Reedy Robert Planetary Science Institute, 85719, Tucson, AZ, USA aut NATIONALLICENCE 773 0- Space Science Reviews Springer Netherlands 163/1-4(2011-12-01), 371-459 0038-6308 163:1-4<371 2011 163 11214 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer