Data Set Overview :  The CheMin instrument determines the mineralogy and elemental composition of powdered samples through the combined application of X-ray diffraction (XRD, producing mineral identification and quantification) and X-ray fluorescence (chemical analysis based on Energy Dispersive Histograms, EDH). This CheMin RDR data set contains tables of energy and X-ray diffraction data derived from raw CheMin observations.  A higher level CheMin RDR data set is derived from these products, the CheMin Mineral Abundance data (MSL-M-CHEMIN-4-RDR-V1.0), which is archived separately.  Processing : CheMin RDR data products are considered CODMAC Level 4 or Resampled Data, equivalent to NASA Level 1B products. The RDR data files are generated from CheMin Level 2 (NASA Level 0) EDR Data (MSL-M-CHEMIN-2-EDR-V1.0), archived separately.  Processing of XRD data consists of conversion of the 2D CCD images of Debye diffraction rings into 1D files of intensity versus 2-theta. Counts within arcs of the Debye rings are adjusted for variable arc lengths intersected by the CCD. Processing of EDH data consists of conversion of digital number (DN) to X-ray energy in keV. Data : The data types available in this data set are described in the RDR SIS and are summarized as follows:  1. Co K-alpha or K-beta XRD single-pixel data summed along 2 theta radii, adjusted for arc length and presented as 2-theta versus intensity tables (product type RD1).  2. Co K-alpha or K-beta split pixel XRD data summed along 2-theta radii, adjusted for arc length and presented as 2-theta versus intensity tables (product type RDS).  3. Co K-alpha or K-beta all-hits XRD data summed along 2-theta radii, adjusted for arc length and presented as 2-theta versus intensity tables (product type RDA).  4. Raw frames processed for XRD analysis, summed along 2-theta radii, adjusted for arc length and presented as 2-theta versus intensity tables (product type RTR).  5. Film images processed for XRD analysis, summed along 2-theta radii, adjusted for arc length and presented as 2-theta versus intensity tables (product type RDF).  6. Energy histograms of all hits converted from DN to energy (product type REA).  7. Energy histograms of single-pixel hits converted from DN to energy (product type RE1).  8. Energy histograms of split-pixel hits converted from DN to energy (product type RES).

Confidence Level Overview : X-ray diffraction reliability and accuracy of mineral identifications is comparable to that of commercial portable XRD instruments such as the Terra system manufactured by inXitu (http://www.inxitu.com/html/Terra.html). This level of performance produces accurate identification and detection for virtually all crystalline phases at abundance greater than ~1 wt%. EDH capability is limited to elements of Z:14 (Si) and higher, due to poor CCD quantum efficiency at low X-ray energies (below 1.7 keV).  Review : The CheMin RDR products are reviewed internally by the CheMin team prior to release to the PDS. PDS also performs an external peer review of the CheMin RDR.  Data Coverage and Quality : This section will be updated with the first release of CheMin RDR data to the PDS.  Limitations : X-ray amorphous materials may be detected as a broad XRD amorphous background but amorphous materials have higher detection limits with poorer accuracy in quantification. Quantification of EDH data (chemical abundances from X-ray diffraction) is not currently possible but is a research effort.  Data Compression : No data compression is used.