Save U, Th, Pb Age Calculations

EPMA Probe

 

Probe Menu Details > Output

Save U, Th, Pb Age Calculations

This menu (U, Th, Pb Age calculation format) will create an output file of standard or unknown samples using code based on Montel’s age calculations written by Julien Allaz and John Donovan for monazite age calculations based on the uranium, thorium and lead concentrations (assuming all lead is radiogenic).

 

In addition the elemental and oxide weight percents, along with single point detection and analytical sensitivity and raw k-ratios, count times, beam current and x, y, z coordinates and relative distance in microns will also be output for all elements.

 

SAMPLE      Sample name (in double quotes)

LINE        Line number

U WT%       Elemental weight percent of uranium

Th WT%      Elemental weight percent of thorium

Pb WT%      Elemental weight percent of  lead

U PPM       Elemental weight percent of uranium in PPM

Th PPM      Elemental weight percent of thorium in PPM

Pb PPM      Elemental weight percent of lead in PPM

Age[My]     Calculated monazite age in millions of years

Calc Pb     Pb calculated (predicted)

%Pb(U       Percent of Pb from radioactive decay of uranium

%Pb(Th)     Percent of Pb from radioactive decay of thorium

 

El (O2)     Oxide weight percent

El WT%      Elemental weight percent

TOTAL       Total weight percent

DAT/TIM     Acquisition date and time in system defined format

X-POS       X stage position

Y-POS       Y stage position

Z-POS       Z stage position

RELDIST     Relative distance (in microns)

BEAMCUR     Beam or probe current (in nA) (array if combined conditions sample)

ABSBCUR     Sample or absorbed current (in nA)

El AT%      Atomic percent

El CDL99    Detection limit in elemental weight percent at 99% confidence

El %ERR     Analytical error in relative percent (one sigma)

El ONTIM    On-peak counting time

El HITIM    High off-peak counting time

El LOTIM    Low off-peak counting time

El K-RAW    Elemental raw k-ratio (unk counts/standard counts)

 

STD_NUM     Primary standard assignment number

STD_NAM     Primary standard assignment name

 

This file format was specified by Julien Allaz and Michael Jercinovic at the University of Massachussetts and cannot be modified for other applications.