analyse_portableOSL: Analyse portable CW-OSL measurements

In R-Lum/Luminescence: Comprehensive Luminescence Dating Data Analysis

Analyse portable CW-OSL measurements

Description

The function analyses CW-OSL curve data produced by a SUERC portable OSL reader and produces a combined plot of OSL/IRSL signal intensities, OSL/IRSL depletion ratios and the IRSL/OSL ratio.

Usage

analyse_portableOSL(
  object,
  signal.integral = NULL,
  invert = FALSE,
  normalise = FALSE,
  mode = "profile",
  coord = NULL,
  plot = TRUE,
  ...
)

Arguments

object	RLum.Analysis (required): object produced by read_PSL2R. The input can be a list of such objects, in which case each input is treated as a separate sample and the results are merged.
signal.integral	numeric (required): A vector specifying the range of channels used to calculate the OSL/IRSL signal. It can be provided as a vector of length 2 such as c(1, 5), or as a sequence such as 1:5, in which case the lowest and highest values define the range.
invert	logical (with default): TRUE flip the plot the data in reverse order.
normalise	logical (with default): whether the OSL/IRSL signals should be normalised to the mean of all corresponding data curves.
mode	character (with default): analysis mode, one of "profile" (the default) or "surface" for surface interpolation.
coord	list matrix (optional): a list or a 2-column matrix with the x and y coordinates for the sampling positions in meters (m), of the same length as the number of samples measured. For example, the coordinates for one sample could be ⁠coord = list(samp1 = c(0.1, 0.2)⁠. If the x coordinates were not measured, x should be set to 0. Note that, in such case, a surface plot cannot be produced.
plot	logical (with default): enable/disable the plot output.
...	other parameters to be passed to modify the plot output. Supported are run to provide the run name (if the input is a list, this is set automatically). Further plot parameters accepted are main, col, xlim (a named list for profile mode), ylim, ylab, xlab. Additional parameters for mode = "profile" are type, pch, grid (TRUE/FALSE), bg_img (a raster object for the background image, usually a profile photo), bg_img_positions (a vector with the four corner positions, see graphics::rasterImage), zlab (here x-axis labelling). Additional parameters for mode = "surface" are surface_value (character with names of the surfaces to plot), col_ramp, legend (TRUE/FALSE), contour (TRUE/FALSE),⁠ ⁠contour_nlevels⁠, ⁠contour_col⁠, ' zlim⁠.

Details

This function only works with RLum.Analysis objects produced by read_PSL2R. It further assumes (or rather requires) an equal amount of OSL and IRSL curves that are pairwise combined for calculating the IRSL/OSL ratio. For calculating the depletion ratios, the cumulative signal of the last n channels (same number of channels as specified by signal.integral) is divided by cumulative signal of the first n channels (signal.integral).

Note: The function assumes the following sequence pattern: ⁠DARK COUNT⁠, IRSL, ⁠DARK COUNT⁠, BSL, ⁠DARK COUNT⁠. Therefore, the total number of curves in the input object must be a multiple of 5, and there must be 3 DARK_COUNT records for each IRSL/BSL pair. If you have used a different sequence, the function will produce an error.

Signal processing The function processes the signals as follows: BSL and IRSL signals are extracted using the chosen signal integral, dark counts are taken in full.

Working with coordinates Usually samples are taken from a profile with a certain stratigraphy. In the past the function calculated an index. With this newer version, you have two option of passing on xy-coordinates to the function:

• (1) Add coordinates to the sample name during measurement. The form is rather strict and has to follow the scheme ⁠_x:<number>|y:<number>⁠. Example: sample_x:0.2|y:0.4.

• (2) Alternatively, you can provide a list or matrix with the (x, y) coordinates of each sample in meters (m) using the coord argument: Example: coord = list(c(0.2, 1), c(0.3,1.2))

If in your profile the x-coordinates were not measured, x should be set to 0. Note that, in such case, a surface plot cannot be produced.

Value

Returns an S4 RLum.Results object with the following elements:

⁠$data⁠
.. $summary: data.frame with the results
.. $data: list with the RLum.Analysis objects
.. $args: list the input arguments

Function version

0.1.3

Author(s)

Christoph Burow, University of Cologne (Germany)
Sebastian Kreutzer, Institute of Geography, Heidelberg University (Germany)
Marco Colombo, Institute of Geography, Heidelberg University (Germany)

See Also

RLum.Analysis, RLum.Data.Curve, read_PSL2R

Examples

## example profile plot
# (1) load example data set
data("ExampleData.portableOSL", envir = environment())

# (2) merge and plot all RLum.Analysis objects
merged <- merge_RLum(ExampleData.portableOSL)
plot_RLum(
 object = merged,
 combine = TRUE,
 records_max = 5,
 legend.pos = "outside")
merged

# (3) analyse and plot
results <- analyse_portableOSL(
  merged,
  signal.integral = 1:5,
  invert = FALSE,
  normalise = TRUE)
get_RLum(results)

R-Lum/Luminescence documentation built on June 9, 2025, 2:40 p.m.