Data Set Overview : The Dynamic Albedo of Neutrons (DAN) is an active/passive neutron spectrometer that measures the abundance and depth distribution of H- and OH-bearing materials (e.g., adsorbed water, hydrated minerals) in a shallow layer (~1 m) of Mars' subsurface along the path of the MSL rover. In active mode, DAN measures the time decay curve (the dynamic albedo) of the neutron flux from the subsurface induced by its pulsing 14 MeV neutron source (Figure 1 shows an example). A detailed description of the DAN instrument and scientific investigation can be found in Litvak et al. (2008).  The MSL DYNAMIC ALBEDO OF NEUTRON DETECTOR consists of 5 RDR data types. Three are a time series collection of science and housekeeping data from the MSL rover. Data are sorted by time, with each data file containing one sol's worth of data. Measurements are assigned to a particular sol based on the start of the collection interval.   Parameters : The DAN RDR data set is composed of five data types. The objective of compiling the DAN RDR is to create a record of the reduced data dervied from the EDR data collected by DAN. The following paragraphs discuss the parameters of interest in each of the data types.  Derived Engineering ------- The DAN engineering data set is produced from the housekeeping data that is in all EDR data types. The raw values are converted to engineering units of volts, amp, or celsius.  Derived Passive ------------ The PASSIVE data set is produced with high voltage applied to the detectors but the PNG is not pulsing. The sum of the counts in the CTN and CETN spectra which are background corrected and adjusted for detector efficiency.  Derived Active ------------ The ACTIVE data is is produced with high voltage applied to the detectors and the PNG is pulsing. The sum of the counts in the CTN and CETN spectra which are background corrected and adjusted for detector efficiency.  Averaged Passive ------------ The PASSIVE data set is produced with high voltage applied to the detectors but the PNG is not pulsing. The average of the Derived Passive data set over some period time. The time over which the data is averaged is included in the data set.  Averaged Active ------------ The ACTIVE data is is produced with high voltage applied to the detectors and the PNG is pulsing. The average of the Derived Active data set over some period time. The time over which the data is averaged is included in the data set.  Processing : DAN's Reduced Data Records (RDR), NASA Level 1 and above products are generated by the DAN team from the EDR data products, which are produced by the Multi-Mission Data Processing and Control System (MPCS) on MSL. MPCS is a component of Real Time Operations (RTO), which itself is part of the MSL Ground Data System (GDS).   Data : The DAN RDR data product contains five types of data.  DAN_DERIVED_ENG DAN housekeeping data in engineering units DAN_DERIVED_PASSIV DAN reduced passive neutron data DAN_DERIVED_ACTIVE DAN reduced active neutron data DAN_AVERAGED_PASSIV DAN averaged reduced passive neutron data DAN_AVERAGED_ACTIVE DAN averaged reduced active neutron data  The first three types are time series of DAN housekeeping and science data. The last two are averaged over some time period.   Coordinate System : This data set will use the standard Mars latitude and an easting longitude to specify location. This spatial information will be calculated using the SPICE tool set along with MSL specific SPICE kernels.  Software : No DAN specific software is provided with this data set.  PDS-labeled images and tables can be viewed with the program NASAView, developed by the PDS and available for a variety of computer platforms from the PDS web site http://pds.nasa.gov/tools/software_download.cfm. There is no charge for NASAView.

Confidence Level Overview : The data presented in the DAN RDR is intended to be processed, and reduced data set released for DAN. Data presented here are an accurate reduction of DAN data using the a derived processing technique.   Review : The DAN RDR was reviewed internally by the DAN team prior to release to the PDS. PDS will also performed an external peer review of the DAN RDR.   Data Coverage and Quality : Data reported are the processed data received from OPGS in the form of EDR. All data received is processed into one of the RDR data types. Data are of good quality as the processing is based on the best available knowledge of the reduction algorithms used.   Limitations : The major limitation of this data set is that gained knowledge as data is received from Mars may require the reprocessing of data alreay delivered the PDS due to modifications in the algorithms used in the data production.  Data Compression : No data compression is used.