analyse_FadingMeasurement(object, structure = c("Lx", "Tx"), signal.integral, background.integral, t_star = "half", n.MC = 100, verbose = TRUE, plot = TRUE, plot.single = FALSE, ...)RLum.Analysis (required): input object with the
measurement data. Alternatively, a list containing RLum.Analysis
objects or a data.frame with three columns
(x = LxTx, y = LxTx error, z = time since irradiation) can be provided.
Can also be a wide table, i.e. a data.frame with a number of colums divisible by 3
and where each triplet has the before mentioned column structure.character (with default): sets the structure of the measurement
data. Allowed are 'Lx' or c('Lx','Tx'). Other input is ignoredvector (required): vector with the
limits for the signal integral. Not required if a data.frame with LxTx values are
provided.vector (required): vector with the
bounds for the background integral. Not required if a data.frame with LxTx values are
provided.character (with default): method for calculating the time elasped
since irradiaton. Options are: 'half', which is $t_star := t_1 + (t_2 - t_1)/2$ (Auclair et al., 2003)
and 'end', which takes the time between irradiation and the measurement step. Default is 'half'integer (with default): number for Monte Carlo runs for the error
estimationlogical (with default): enables/disables verbose modelogical (with default): enables/disables plot outputlogical (with default): enables/disables single plot
mode, i.e. one plot window per plot. Alternatively a vector specifying the plot to be drawn, e.g.,
plot.single = c(3,4) draws only the last two plotsRLum.Results object is returned:Slot: @data| OBJECT | TYPE |
COMMENT |
fading_results |
data.frame |
results of the fading measurement in a table |
fit |
lm |
object returned by the used linear fitting function lm |
rho_prime |
data.frame |
results of rho' estimation after Kars et al. 2008 |
LxTx_table |
data.frame |
| Lx/Tx table, if curve data had been provided |
irr.times |
integer |
vector with the irradiation times in seconds |
| OBJECT | TYPE |
COMMENT |
call |
call |
the original function call |
calc_FadingCorr.Fitting and error estimation
For the fitting the function lm is used without applying weights. For the
error estimation all input values, except tc, as the precision can be consdiered as sufficiently
high enough with regard to the underlying problem, are sampled assuming a normal distribution
for each value with the value as the mean and the provided uncertainty as standard deviation.
Density of recombination centres
The density of recombination centres, expressed by the dimensionless variable rho', is estimated
by fitting equation 5 in Kars et al. 2008 to the data. For the fitting the function
nls is used without applying weights. For the error estimation the same
procedure as for the g-value is applied (see above).
Huntley, D.J., Lamothe, M., 2001. Ubiquity of anomalous fading in K-feldspars and the measurement and correction for it in optical dating. Canadian Journal of Earth Sciences 38, 1093-1106. doi:10.1139/cjes-38-7-1093
Kars, R.H., Wallinga, J., Cohen, K.M., 2008. A new approach towards anomalous fading correction for feldspar IRSL dating-tests on samples in field saturation. Radiation Measurements 43, 786-790. doi:10.1016/j.radmeas.2008.01.021
calc_OSLLxTxRatio, read_BIN2R, read_XSYG2R,
extract_IrradiationTimes
## load example data (sample UNIL/NB123, see ?ExampleData.Fading)
data("ExampleData.Fading", envir = environment())
##(1) get fading measurement data (here a three column data.frame)
fading_data <- ExampleData.Fading$fading.data$IR50
##(2) run analysis
g_value <- analyse_FadingMeasurement(
fading_data,
plot = TRUE,
verbose = TRUE,
n.MC = 10)
##(3) this can be further used in the function
## to correct the age according to Huntley & Lamothe, 2001
results <- calc_FadingCorr(
age.faded = c(100,2),
g_value = g_value,
n.MC = 10)
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