numOSL (version 2.0)

fastED: Fast-component equivalent dose calculation

Description

Estimating a fast-component equivalent dose using decay curves obtained from the single aliquot regenerative-dose (SAR) sequence.

Usage

fastED(Sigdata, Redose, ncomp = 2, constant = TRUE,   control.args = list(), typ = "cw", model = "exp",  origin = FALSE, ErrorMethod = "mc",  nsim = 1000, weight = TRUE)

Arguments

Sigdata

matrix(required): a series of decay curves stored in a matrix column by column, the first column denotes stimulation time values

Redose

vector(required): regenerative dose values. Example, Redose=c(1,2,3,4,0,1)

ncomp

integer(with default): number of decomposed components

constant

logical(with default): subtract a constant background or not

control.args

list(with default): arguments used in the differential evolution algorithm, see function decomp for details

typ

character(with default): type of an OSL decay curve, only CW-OSL decay curve can be analyzed currently

model

character(with default): model used for growth curve fitting, see function fitGrowth for available models

origin

logical(with default): force the fitted growth curve to pass the origin or not

ErrorMethod

character(with default): method used for assessing the standard error of an equivalent dose, see function calED for details

nsim

integer(with default): number of Monte Carlo simulations used for equivalent dose error estimation if ErrorMethod="mc"

weight

character(with default): perform growth curve fitting using a weighted or an un-weighted procedure, see function fitGrowth for details

Value

Return a list containing the following elements:

decayPars

estimated parameters of fitted decay curves

Curvedata

data used for constructing the fast-component growth curve

Ltx

standardised natural dose signal of the fast-component and its standard error

LMpars

optimizaed parameters for the fitted growth curve

value

minimized objective for the fitted growth curve

fastED

fast-component equivalent dose and its standard error

RecyclingRatio

fast-component recycling ratio and its standard error

Recuperation

fast-component recuperation and its standard error (in percent)

Details

Function fastED is used to estimate a fast-component equivalent dose using data sets obtained from the SAR protocol (Murray and Wintle, 2000). The routine trys to decompose a series of decay curves to a specified number of components, then the numbers of trapped electrons from the fast-component will be used to construct the growth curve to estimate a fast-component equivalent dose. See function decomp, fitGrowth, and calED for more details concerning decay curve decomposition, growth curve fitting, and equivalent dose calculation.

References

Li SH, Li B, 2006. Dose measurement using the fast component of LM-OSL signals from quartz. Radiation Measurements, 41(5): 534-541.

Murray AS, Wintle AG, 2000. Luminescence dating of quartz using improved single-aliquot regenerative-dose protocol. Radiation Measurements, 32(1): 57-73.

See Also

analyst; calED; decomp; fitGrowth

Examples

 data(Signaldata)
 # Use only the first two regenerative dose values. 
 fastED(Signaldata$cw[,-(8:15)],Redose=c(80,160)*0.13,model="line",
        control.args=list(factor=5,maxiter=50),origin=TRUE)
 # Use all regenerative dose values (except the zero-dose).
 # fastED(Signaldata$cw[,c(-12,-13)],Redose=c(80,160,240,320,80)*0.13,
 #        ncomp=3,constant=FALSE)