analyse_IRSAR.RF: Analyse IRSAR RF measurements

Description

Function to analyse IRSAR RF measurements on K-feldspar samples, performed using the protocol according to Erfurt et al. (2003)

Usage

analyse_IRSAR.RF(object, sequence.structure = c("NATURAL", "REGENERATED"), 
    fit.range.min, fit.range.max, fit.trace = FALSE, fit.MC.runs = 10, 
    output.plot = TRUE, xlab.unit = "s", legend.pos = "bottom", 
    ...)

Arguments

object

RLum.Analysis (required): input object containing data for protocol analysis

sequence.structure

vector character (with default): specifies the general sequence structure. Allowed steps are NATURAL, REGENERATED

fit.range.min

integer (optional): set the minimum channel range for signal fitting. Usually the entire data set is used for curve fitting, but there might be reasons to limit the channels used for fitting.

fit.range.max

integer (optional): set maximum channel range for signal fitting. Usually the entire data set is used for curve fitting, but there might be reasons to limit the channels used for fitting.

fit.trace

logical (with default): trace fitting (for debugging use)

fit.MC.runs

numeric (with default): set number of Monte Carlo runs for start parameter estimation. Note: Higher values will significantly increase the calculation time

output.plot

logical (with default): plot output (TRUE or FALSE)

xlab.unit

character (with default): set unit for x-axis

legend.pos

character (with default): useful keywords are bottomright, bottom, bottomleft, left, topleft, top, topright, right

...

further arguments that will be passed to the plot output. 
Currently supported arguments are main, xlab, ylab

`Value`

A plot (optional) and an RLum.Results object is returned 
containing the following elements:
De.valuesdata.frame containing De-values with error 
(gray dashed lines in the plot) and further parameters
fitnls nlsModel object
Note: The output (De.values) should be accessed using the 
function get_RLum.Results

`Details`

The function performs an IRSAR analysis described for feldspar samples by 
Erfurt et al. (2003) assuming a negligible sensitivity change of the RF signal.
General Sequence Structure (according to Erfurt et al. (2003))
Measuring IR-RF intensity of the natural dose for a few seconds ($D_{natural}$)
Bleach the samples under solar conditions for at least 30 min without changing 
the geometry
Waiting for at least one hour
Regeneration of the IR-RF signal to at least the natural level
Fitting data with a stretched exponential function
Calculate the the palaedose$D$using the parameters from the fitting
Function Used For The Fitting (according to Erfurt et al. (2003))
$$\phi(D) = \phi_{0}-\Delta\phi(1-exp(-\lambda*D))^\beta$$
with $\phi(D)$ the dose dependent IR-RF flux, $\phi_{0}$ the inital IR-RF flux, 
$\Delta\phi$ the dose dependent change of the IR-RF flux, $\lambda$ 
the exponential parameter, $D$ the dose and $\beta$ the dispersive 
factor.

To obtain the palaedose the function is changed to:
$$D = ln(-(\phi(D) - \phi_{0})/(-\lambda*\phi)^{1/\beta}+1)/-\lambda$$
The fitting is done using the port algorithm of the nls function.

`References`

Buylaert, J.P., Jain, M., Murray, A.S., Thomsen, K.J., Lapp, T., 2012. 
IR-RF dating of sand-sized K-feldspar extracts: A test of accuracy. 
Radiation Measurements 1-7. doi: 10.1016/j.radmeas.2012.06.021

Erfurt, G., Krbetschek, M.R., 2003. IRSAR - A single-aliquot regenerative-dose 
dating protocol applied to the infrared radiofluorescence (IR-RF) of coarse- grain 
K-feldspar. Ancient TL 21, 35-42.

Erfurt, G., 2003. Infrared luminescence of Pb+ centres in potassium-rich feldspars. 
physica status solidi (a) 200, 429-438.

Erfurt, G., Krbetschek, M.R., 2003. Studies on the physics of the infrared 
radioluminescence of potassium feldspar and on the methodology of its application 
to sediment dating. Radiation Measurements 37, 505-510.

Erfurt, G., Krbetschek, M.R., Bortolot, V.J., Preusser, F., 2003. 
A fully automated multi-spectral radioluminescence reading system for 
geochronometry and dosimetry. Nuclear Instruments and Methods in Physics Research 
Section B: Beam Interactions with Materials and Atoms 207, 487-499.

Trautmann, T., 2000. A study of radioluminescence kinetics of natural feldspar 
dosimeters: experiments and simulations. Journal of Physics D: Applied Physics 33, 2304-2310.

Trautmann, T., Krbetschek, M.R., Dietrich, A., Stolz, W., 1998. 
Investigations of feldspar radioluminescence: potential for a new dating technique. 
Radiation Measurements 29, 421-425.

Trautmann, T., Krbetschek, M.R., Dietrich, A., Stolz, W., 1999. Feldspar 
radioluminescence: a new dating method and its physical background. 
Journal of Luminescence 85, 45-58.

Trautmann, T., Krbetschek, M.R., Stolz, W., 2000. A systematic study of the 
radioluminescence properties of single feldspar grains. 
Radiation Measurements 32, 685-690.

`See Also`

RLum.Analysis, RLum.Results,
get_RLum.Results, nls

`Examples`

Run this code##load data
data(ExampleData.RLum.Analysis, envir = environment())

##perform analysis
temp <- analyse_IRSAR.RF(object = IRSAR.RF.Data)
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