fastED: Fast-component equivalent dose calculation

Description Usage Arguments Details Value Note References See Also Examples

View source: R/fastED.R

Description

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

Usage

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fastED(Sigdata, Redose, delay.off = c(0,0), ncomp = 2, 
       constant = TRUE, control.args = list(), typ = "cw", 
       model = "gok", origin = FALSE, errMethod = "sp", 
       nsim = 500, weight.decomp = FALSE, 
       weight.fitGrowth = TRUE, trial = TRUE, 
       nofit.rgd = NULL, outpdf = NULL, log = "x", 
       lwd = 2, test.dose = NULL, agID = NULL)

Arguments

Sigdata

matrix(required): a series of decay curves stored in a matrix column by column, the first column denotes stimulation time values, see details. Data structure of this kind can be obtained using function pickBINdata by setting argument force.matrix=TRUE, see examples

Redose

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

delay.off

vector(with default): a two-elment vector indicating the "Delay" and "Off"
values of the decay curves, i.e., delay.off[1]=Delay,delay.off[2]=Off

ncomp

integer(with default): number of decomposed components

constant

logical(with default): logical value indicating if a constant background should be subtracted from the decay curve, see function decomp for details

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): logical value indicating if the growth curve should be forced to pass the origin

errMethod

character(with default): method used for equivalent dose error assessment. See function calED for details

nsim

integer(with default): desired number of randomly simulated equivalent dose obtained by Monte Carlo simulation

weight.decomp

character(with default): logical value indicating if the decay curve should be fitted using a weighted procedure, see function decomp for details

weight.fitGrowth

character(with default): logical value indicating if the growth curve should be fitted using a weighted procedure, see function fitGrowth for details

trial

logical(with default): logical value indicating if the growth curve should be fitted using other models if the given model fails, see function fitGrowth for details

nofit.rgd

integer(optional): regenerative doses that will not be used during the fitting. For example, if nofit.rgd=1 then the first regenerative dose will not be used during fast-component growth curve fitting

outpdf

character(optional): if specified, results of fast-component equivalent dose calculation will be written to a PDF file named "outpdf" and saved to the current work directory

log

character(with default): a character string which contains "x" if the x axis is to be logarithmic, "y" if the y axis is to be logarithmic and "xy" or "yx" if both axes are to be logarithmic

lwd

numeric(with default): width of curves (lines)

test.dose

numeric(optional): test dose of decay curves

agID

vector(optional): a three-elemenet vector indicating aliquot (grain) ID, i.e.,
agID[1]=NO, agID[2]=Position, agID[3]=Grain

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, respectively.

Argument Sigdata is a column-matrix made up with stimulation time values and a number of decay curves:

Column.no Description
I Stimulation time values
II Natural-dose signal values
III Test-dose signal values for the natural-dose
IV The 1th Regenerative-dose signal values
V Test-dose signal values for the 1th regenerative-dose
VI The 2th regenerative-dose signal values
VII Test-dose signal values for the 2th regenerative-dose
... ...

Value

Return an invisible list containing the following elements:

decomp.pars

a list containing optimized parameters of successfully fitted decay curves

Curvedata

data sets used for building the fast-component growth curve

Ltx

sensitivity-corrected natural-dose fast-component signal and its standard error

LMpars

optimizaed parameters for the fast-component growth curve

value

minimized objective for the fast-component growth curve

avg.error

average fit error for the fast-component growth curve

RCS

reduced chi-square value for the fast-component growth curve

FOM

figure of merit value for the fast-component growth curve in percent

calED.method

method used for fast-component equivalent dose calculation, i.e.,
"Interpolation" or "Extrapolation"

mcED

randomly simulated fast-component equivalent doses

ED

fast-component equivalent dose and its standard error

ConfInt

68 percent and 95 percent confidence interval of fast-component equivalent dose

RecyclingRatio1

the first fast-component recycling ratio and its standard error

RecyclingRatio2

the second fast-component recycling ratio and its standard error

RecyclingRatio3

the third fast-component recycling ratio and its standard error

Recuperation1

the first fast-component recuperation (i.e., ratio of the sensitivity-corrected
zero-dose signal to natural-dose signal) and its standard error in percent

Recuperation2

the second fast-component recuperation (i.e., ratio of the sensitivity-corrected zero-dose signal to maximum regenerative-dose signal) and its standard error in percent

Note

Argument test.dose and agID have nothing to do with fast-component equivalent dose calculation. They are used only for plotting purpose.

The number of trapped electrons that corresponds to the largest decay rate will be regarded as the fast-component signal, which cannot always ensure that a pure fast-component signal be extracted if an ultra-fast decaying component appears.

The authors thank Professor Sheng-Hua Li and Professor Geoff Duller for their helpful discussions concerning fast-component 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

pickBINdata; Signaldata;
fitGrowth; decomp; calED

Examples

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 ### Example 1 (not run):
 # data(Signaldata)
 # fastED(Signaldata$cw,Redose=c(80,160,240,320,0, 80)*0.13,
 #        ncomp=3, constant=FALSE, outpdf="fastED1")

 ### Example 2 (not run):
 # data(BIN)
 # obj_pickBIN <- pickBINdata(BIN, Position=6, Grain=0, 
 #                            LType="OSL", force.matrix=TRUE)
 # fastED(obj_pickBIN$BINdata[[1]], ncomp=2, constant=TRUE,
 #        Redose=c(100,200,300,400,0,100)*0.13, outpdf="fastED2")

numOSL documentation built on May 18, 2018, 9:04 a.m.