Luminescence (version 0.8.6)

Second2Gray: Converting equivalent dose values from seconds (s) to gray (Gy)

Description

Conversion of absorbed radiation dose in seconds (s) to the SI unit gray (Gy) including error propagation. Normally used for equivalent dose data.

Usage

Second2Gray(data, dose.rate, error.propagation = "omit")

Arguments

data

data.frame (required): input values, structure: data (values[,1]) and data error (values [,2]) are required

dose.rate

'>RLum.Results, data.frame or numeric (required): RLum.Results needs to be orginated from the function calc_SourceDoseRate, for vector dose rate in Gy/s and dose rate error in Gy/s

error.propagation

character (with default): error propagation method used for error calculation (omit, gaussian or absolute), see details for further information

Value

Returns a data.frame with converted values.

Function version

0.6.0 (2018-01-21 17:22:38)

How to cite

Kreutzer, S., Dietze, M., Fuchs, M.C. (2018). Second2Gray(): Converting equivalent dose values from seconds (s) to gray (Gy). Function version 0.6.0. In: Kreutzer, S., Burow, C., Dietze, M., Fuchs, M.C., Schmidt, C., Fischer, M., Friedrich, J. (2018). Luminescence: Comprehensive Luminescence Dating Data Analysis. R package version 0.8.6. https://CRAN.R-project.org/package=Luminescence

Details

Calculation of De values from seconds (s) to gray (Gy)

$$De [Gy] = De [s] * Dose Rate [Gy/s])$$

Provided calculation error propagation methods for error calculation (with 'se' as the standard error and 'DR' of the dose rate of the beta-source):

(1) omit (default)

$$se(De) [Gy] = se(De) [s] * DR [Gy/s]$$

In this case the standard error of the dose rate of the beta-source is treated as systematic (i.e. non-random), it error propagation is omitted. However, the error must be considered during calculation of the final age. (cf. Aitken, 1985, pp. 242). This approach can be seen as method (2) (gaussian) for the case the (random) standard error of the beta-source calibration is 0. Which particular method is requested depends on the situation and cannot be prescriptive.

(2) gaussian error propagation

$$se(De) [Gy] = \sqrt((DR [Gy/s] * se(De) [s])^2 + (De [s] * se(DR) [Gy/s])^2)$$

Applicable under the assumption that errors of De and se are uncorrelated.

(3) absolute error propagation

$$se(De) [Gy]= abs(DR [Gy/s] * se(De) [s]) + abs(De [s] * se(DR) [Gy/s])$$

Applicable under the assumption that errors of De and se are not uncorrelated.

References

Aitken, M.J., 1985. Thermoluminescence dating. Academic Press.

See Also

calc_SourceDoseRate

Examples

# NOT RUN {
##(A) for known source dose rate at date of measurement
## - load De data from the example data help file
data(ExampleData.DeValues, envir = environment())
## - convert De(s) to De(Gy)
Second2Gray(ExampleData.DeValues$BT998, c(0.0438,0.0019))





##(B) for source dose rate calibration data
## - calculate source dose rate first
dose.rate <-  calc_SourceDoseRate(measurement.date = "2012-01-27",
                                  calib.date = "2014-12-19",
                                  calib.dose.rate = 0.0438,
                                  calib.error = 0.0019)
# read example data
data(ExampleData.DeValues, envir = environment())

# apply dose.rate to convert De(s) to De(Gy)
Second2Gray(ExampleData.DeValues$BT998, dose.rate)

# }