NARA 5SDH-2
NARA 5SDH-2
14/13 ratio = 14Ciavg(part)
/ 13Ciavg(part)
14/12 ratio = 14Ciavg(part) / 12Ciavg(part)
13/12 ratio = 13Ciavg(part) / 12Ciavg(part)
for example:
13/12 ratio =
110pnA / 10puA
13/12 ratio = 0.011
13/12 ratio *= 100 convert to percent
13/12 ratio = 1.1 %
14/12 ratio = 1e-17A / 10puA
14/12 ratio = 1.0e-12
In the case of the abundant isotopes (13C and 12C) the current value is sampled one time during each jumping cycle. The average of the entire set of current measurements for one isotope is computed as follows (using 13C as an example):
13Civg = sum(13Ci)/number_of_jumping_cycles
where sum(13Ci) is the summation of the entire set of 13C current measurements.
Then particle current is calculated:
13Civg(part) = 13Ciavg/charge_state
For rare isotopes (14C in this case) the process is somewhat more complicated because individual particles are counted and this information must be converted to an average current.
First the total charge is calculated:
14C_chg = Total_GatedParticle_Count * e
where e is the charge of one electron (1.601e-19 coloumbs)
Next the total amount of 14C data collection time is computed:
Ttotal = time_per_jumping_cycle * total_number_of_jumping_cycles
Finally charge is converted to average current.
14Civg = 14C_chg / Ttotal
Since all calculations are done on individual particles and converted to charge by multiplying the number of particles by the charge of an electron the answer is already in particle current so no further calculation is needed.
