Rigorous Data Reduction and Error Propagation of Ar40 / Ar39 Data
Calculate the arithmetic mean
Average all the data collected on the same day.
Apply a blank correction
The blankcorrected class
Detector calibration
Cl-interference correction
Merge a list of logratio data
Correct for radioactive decay occurred since irradiation
Extrapolation to 'time zero'
Compute the mass fractionation correction
Calculate the 40Ar*/39ArK-ratios
Calculate 40Ar/39Ar ages
Calculate the irradiation parameter ('J factor')
Select a subset of isotopes from a dataset
define the interference corrections
Load mass spectrometer data
Load the irradiation schedule
The logratios class
Apply the mass fractionation correction
Create a new redux object
Set or get Ar-Ar_Redux parameters
The PHdata class
Plot a time resolved mass spectrometry signal
Plot a matrix with correlation coefficients
Process logratio data and calculate 40Ar/39Ar ages
Read mass spectrometer data
The redux class
Export ArArRedux data to IsoplotR
The results class
Select a subset of some data
Summary table
The timeresolved class
Calculate the weighted mean age
Processes noble gas mass spectrometer data to determine the isotopic composition of argon (comprised of Ar36, Ar37, Ar38, Ar39 and Ar40) released from neutron-irradiated potassium-bearing minerals. Then uses these compositions to calculate precise and accurate geochronological ages for multiple samples as well as the covariances between them. Error propagation is done in matrix form, which jointly treats all samples and all isotopes simultaneously at every step of the data reduction process. Includes methods for regression of the time-resolved mass spectrometer signals to t=0 ('time zero') for both single- and multi-collector instruments, blank correction, mass fractionation correction, detector intercalibration, decay corrections, interference corrections, interpolation of the irradiation parameter between neutron fluence monitors, and (weighted mean) age calculation. All operations are performed on the logs of the ratios between the different argon isotopes so as to properly treat them as 'compositional data', sensu Aitchison [1986, The Statistics of Compositional Data, Chapman and Hall].