Functions for calculating basic units used in radiocarbon measurements.

`c14_age()`

calculates the conventional radiocarbon age (CRA) from a fraction
modern measurement.

`c14_f14c()`

reverse-calculates the fractionation-corrected fraction modern
value (F^14CF14C or pMpM) of a radiocarbon age.

## Usage

```
c14_age(x, decay = c14::c14_decay_libby)
c14_f14c(x, decay = c14::c14_decay_libby)
```

## Arguments

- x
For

`c14_age()`

, a vector of fraction modern (F^14CF14C) measurements. For`c14_f14c()`

, a vector of conventional radiocarbon ages.- decay
Decay constant. The default is the Libby constant (

`c14_decay_libby`

), which is the standard for calculating conventional radiocarbon ages. Use`c14_decay_cambridge`

for the Cambridge constant, or a single numeric for other values.

## Details

`c14_age()`

calculates the conventional radiocarbon age, tt,
as defined by Stuiver1977;textualc14:

t = -1F^14Ct = -1/l * ln(F^14C)

`c14_f14c()`

implements the inverse of this function:

F^14C = e^- tF14C = e^(-lt)

The decay constant conventionally used for calculating radiocarbon ages is the Libby decay constant, _L=8033^-1lL = 1/8033. An alternative is the Cambridge decay constant, _C=8267^-1lC = 1/8267 Stenstrom2011c14.

Reported radiocarbon ages are usually rounded based on the magnitude of the error Stuiver1977c14. For this reason, reverse-calculating fraction modern from a radiocarbon age is unlikely to return the precise original measurement of the sample.

Where available, fraction modern is the recommended measurement for calibration Bronk_Ramsey2008c14.