convert_CW2pLM: Transform a CW-OSL curve into a pLM-OSL curve

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

Transform a CW-OSL curve into a pLM-OSL curve

Description

Transforms a conventionally measured continuous-wave (CW) curve into a pseudo linearly modulated (pLM) curve using the equations given in Bulur (2000).

Usage

convert_CW2pLM(values)

CW2pLM(values)

Arguments

values

RLum.Data.Curve or data.frame (required): RLum.Data.Curve data object. Alternatively, a data.frame of the measured curve data of type stimulation time (t) (values[,1]) and measured counts (cts) (values[,2]) can be provided.

Details

According to Bulur (2000) the curve data are transformed by introducing two new parameters P (stimulation period) and u (transformed time):

P=2*max(t)

u=\sqrt{(2*t*P)}

The new count values are then calculated by

ctsNEW = cts(u/P)

and the returned data.frame is produced by: data.frame(u,ctsNEW)

The output of the function can be further used for LM-OSL fitting.

Value

The function returns the same data type as the input data type with the transformed curve values (data.frame or RLum.Data.Curve).

Function version

0.4.2

Note

The transformation is recommended for curves recorded with a channel resolution of at least 0.05 s/channel.

Author(s)

Sebastian Kreutzer, Institute of Geography, Heidelberg University (Germany)

References

Bulur, E., 2000. A simple transformation for converting CW-OSL curves to LM-OSL curves. Radiation Measurements, 32, 141-145.

Further Reading

Bulur, E., 1996. An Alternative Technique For Optically Stimulated Luminescence (OSL) Experiment. Radiation Measurements, 26, 701-709.

See Also

CW2pHMi, CW2pLMi, CW2pPMi, fit_LMCurve, lm, RLum.Data.Curve

Examples

##read curve from CWOSL.SAR.Data transform curve and plot values
data(ExampleData.BINfileData, envir = environment())

##read id for the 1st OSL curve
id.OSL <- CWOSL.SAR.Data@METADATA[CWOSL.SAR.Data@METADATA[,"LTYPE"] == "OSL","ID"]

##produce x and y (time and count data for the data set)
x<-seq(CWOSL.SAR.Data@METADATA[id.OSL[1],"HIGH"]/CWOSL.SAR.Data@METADATA[id.OSL[1],"NPOINTS"],
       CWOSL.SAR.Data@METADATA[id.OSL[1],"HIGH"],
       by = CWOSL.SAR.Data@METADATA[id.OSL[1],"HIGH"]/CWOSL.SAR.Data@METADATA[id.OSL[1],"NPOINTS"])
y <- unlist(CWOSL.SAR.Data@DATA[id.OSL[1]])
values <- data.frame(x,y)

##transform values
values.transformed <- convert_CW2pLM(values)

##plot
plot(values.transformed)

R-Lum/Luminescence documentation built on March 1, 2025, 12:43 a.m.