Mikewong

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Online site for SAM-related scripts contributed by Mike Wong (generally atmospheric). See also Melissa Trainer's page.

Igor scripts for SAM data anaylsis

Function Script Notes
Background correction Media:bg.ipf Things to do to your data before using this BG script:
  • Import SAM data into Igor as waves: one wave for the time series, one for the cps
  • Apply your own deadtime correction to the data
  • Figure out what experiment interval you'll use for the BG correction, convert to sec if needed
  • Determine whether BG interval is better fit by a constant or a decaying exponential

What this BG script does:

  • Fit BG to selected interval
  • Create a new, BG-corrected wave
  • Create a new BG-uncertainty wave (same value at every point)
  • BG correction applied is constant (i.e., choosing exponential BG only helps determine accurate constant BG level)
  • BG uncertainty is empirically based on scatter in data within BG region
  • Some details of BG fit are stored in the "Notes" field of the new BG-corrected wave

Example screen shot: Bg.ipf.screenshot.png

Subtract contamination Media:killfrag.ipf Things to do to your data before using this subtraction script:
  • Import SAM data into Igor as waves: one wave for the time series, one for the cps
  • Apply your own deadtime and background correction to all data used

What this subtraction script does:

  • Iterpolate parent cps to timesteps of daughter m/z
  • Create new wave, [new] = [daughter] - frac * [parent],
    where frac is the user-specified expected daughter/parent count ratio

Example screen shot: Killfrag.ipf.screenshot.png

Make count ratio Media:makeratio.ipf Things to do to your data before using this ratio script:
  • Import SAM data into Igor as waves: one wave for the time series, one for the cps
  • Apply your own deadtime and background correction to all data used

What this ratio script does:

  • Interpolate numerator cps to timesteps of denominator m/z
  • Create new wave, ratio of the input waves

Example screen shot: Makeratio.ipf.screenshot.png