analyse_portableOSL: Analyse portable CW-OSL measurements

In 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): RLum.Analysis object produced by read_PSL2R. The input can be a list of such objects, in such case each input is treated as a separate sample and the results are merged.
signal.integral	numeric (required): A vector of two values specifying the lower and upper channel used to calculate the OSL/IRSL signal. Can be provided in form of c(1, 5) or 1:5.
invert	logical (with default): TRUE flip the plot the data in reverse order.
normalise	logical (with default): TRUE to normalise the OSL/IRSL signals to the mean of all corresponding data curves.
mode	character (with default): defines the analysis mode, allowed are "profile" (the default) and "surface" for surface interpolation. If you select something else, nothing will be plotted (similar to plot = FALSE).
coord	list matrix (optional): a list or matrix of the same length as number of samples measured with coordinates for the sampling positions. Coordinates are expected to be provided in meter (unit: m). Expected are x and y coordinates, e.g., ⁠coord = list(samp1 = c(0.1, 0.2)⁠. If you have not measured x coordinates, please x should be 0.
plot	logical (with default): enable/disable 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 are surface_values (character with value to plot), legend (TRUE/FALSE), col_ramp (for surface mode), contour (contour lines TRUE/FALSE in surface mode), grid (TRUE/FALSE), col, pch (for profile mode), xlim (a name list for profile mode), ylim, zlim (surface mode only), ylab, xlab, zlab (here x-axis labelling), main, bg_img (for profile mode background image, usually a profile photo; should be a raster object), bg_img_positions (a vector with the four corner positions, cf. graphics::rasterImage)

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. If you have written a different sequence, the analysis function will (likely) not work!.

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 sample coordinates. Example: coord = list(c(0.2, 1), c(0.3,1.2))

Please note that the unit is meter (m) and the function expects always xy-coordinates. The latter one is useful for surface interpolations. If you have measured a profile where the x-coordinates to not measure, x-coordinates should be 0.

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

0.1.0

How to cite

Burow, C., Kreutzer, S., 2024. analyse_portableOSL(): Analyse portable CW-OSL measurements. Function version 0.1.0. In: Kreutzer, S., Burow, C., Dietze, M., Fuchs, M.C., Schmidt, C., Fischer, M., Friedrich, J., Mercier, N., Philippe, A., Riedesel, S., Autzen, M., Mittelstrass, D., Gray, H.J., Galharret, J., 2024. Luminescence: Comprehensive Luminescence Dating Data Analysis. R package version 0.9.24. https://CRAN.R-project.org/package=Luminescence

Author(s)

Christoph Burow, University of Cologne (Germany), Sebastian Kreutzer, Institute of Geography, Ruprecht-Karl University of Heidelberg, Germany , RLum Developer Team

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)

Luminescence documentation built on June 22, 2024, 9:54 a.m.