ACE Output Variables
After a sample has been dated ACE lists variables generated during the experiment, including computed age, production rates, and scaling factors. These are defined below.
| experiment |
The name of the experiment used to compute a sample age (string) |
| age | The sample age computed by the experiment. The age is rounded up to the nearest ACE timestep, so that if the actual age is 10250 yr and the time step is 100 yr, the given age will be 10300 yr (yr) |
| age uncertainty |
The uncertainty in the age due to uncertainties in the sample inventory, rounded up to the nearest timestep (yr) |
| age uncertainty total |
The uncertainty in the computed age due to uncertainties in both the sample inventory and in the experiment HLSL production rates, rounded up to the nearest timestep (yr) |
| atmospheric pressure |
The pressure at the sample site at the last timestep. Atmospheric pressure will only change with time if the experiment incorporates atmospheric variability (such as created by sea level change), or if the sample is at a tectonically active site (where tectonic rate ≠ 0) and the sample is therefore moving through the atmosphere. Units are g/cm2, to convert to mb divide by 1.01959 |
| cosmogenic inventory | The cosmogenic inventory of the sample. For non-36Cl samples, this is the same as measured inventory, which is an input. For 36Cl samples, this is the measured inventory minus the nucleogenic inventory (0→1E7 atoms/g) |
| cosmogenic inventory uncertainty | the uncertainty in the cosmogenic inventory. For non-36Cl samples, this is the same as measured inventory uncertainty, the uncertainty in the measured inventory. For 36Cl samples, this is the square root of the sum of squares of the uncertainty in the measured inventory and the uncertainty in the nucleogenic inventory, for which ACE assumes is 20% of the nucleogenic inventory. (0→1E4 atoms/g) |
| production rate total | Is the local production rate due to all processes averaged over the age of the sample (atoms/g/yr) |
| production rate invariant | Is the ‘effective’ time invariant local production rate for the sample (atoms/g/yr). For experiments where the production rate changes with time, this will be different from production rate total, and can be thought of as an ‘equivalent’ production rate if the production rates did not change with time. See the section on multiple nuclide analysis for an example of a time invariant production rate calculation. |
| production rate spallation | The production rate for spallation averaged over the age of the sample. For 36Cl samples, this value is the average production rate due to the spallation of Calcium and Potassium. For non-36Cl samples, this value is the average production rate due to spallation (atoms/g/yr) |
| scaling spallation | The local scaling for spallation averaged over the age of the sample. (dimensionless) |
| production rate muons | For unstable (10Be, 14C, 26Al, 36Cl) nuclides, this is the production rate due to fast and slow muons averaged over the age of the sample (atoms/g/yr) |
| scaling fast muons | For unstable (10Be, 14C, 26Al, 36Cl) nuclides, this is the scaling for fast muons averaged over the age of the sample (dimensionless) |
| scaling slow muons | For unstable (10Be, 14C, 26Al, 36Cl) nuclides, this is the scaling for slow muons averaged over the age of the sample (dimensionless) |
| production rate low energy | For 36Cl samples, this is the local production rate due to thermal and epithermal neutrons averaged over the age of the sample (atoms/g/yr). For non-36Cl samples, this is not used. |
| scaling low energy | For 36Cl samples, this is the scaling for thermal and epithermal neutrons averaged over the age of the sample. For non-36Cl samples, this is not used (dimensionless) |