Natural gamma radiation (NGR)

Natural gamma radiation (NGR) data in the ~0.1 to 3.0 MeV range were measured using eight custom-designed sodium iodide (thallium) [NaI(Tl)] detectors arranged along the core measurement axis at 20 cm intervals. The NGR system uses layers of passive shielding (lead) and active shielding (plastic scintillators and coincidence electronics) to reduce the cosmic-ray signal for low-count analysis of sediment core sections and to obtain the maximum signal-to-noise ratio. Data are reported on a total counts per second basis and the raw spectral files are available as compressed files for later analysis.

Data File format

    Exp: expedition number
    Site: site number
    Hole: hole number
    Core: core number
    Type: type indicates the coring tool used to recover the core (typical types are F, H, R, X).
    Sect: section number
    Offset (cm): position of the observation made, measured relative to the top of a section.
    Depth CSF-A (m): location of the observation expressed relative to the top of a hole.
    Depth [other] (m): location of the observation expressed relative to the top of a hole. The location is presented in a scale selected by the science party or the report user.
    NGR total counts (cps): rate of natural gamma radiation across the entire spectrum of ~0.1-3 MeV.
    Absolute error (cps): absolute error of measurement (1 divided by the square root of the total counts divided by the number of seconds).
    NGR zip file: zip file containing calibration, background, raw, and reduced data.
    Timestamp (UTC): date and time which the observation was made.
    Text ID: automatically generated unique database identifier for a sample, visible on printed labels.
    Test No: unique number associated with the instrument measurement steps that produced these data. 
    Sample comments: observations recorded about the sample itself.
    Test comments: observations about a measurement or the measurement process; some measurement observations may be under Result comments.
    Result comments: observations about a measurement or the measurement process; some measurement observations may be under Test comments.