ACE Electron Proton Alpha Monitor (EPAM) 5-Minute and 12-second Averaged Data
Notes on the comma-separated-variable (CSV) ASCII files provided by Fundamental Technologies, LLC
The data in the CSV files consist of count rates of solar ions and electrons, including both sectored and
unsectored rates. The data are in comma-separated-variable (CSV) ASCII files.
Explanation of EPAM Comma Separated Variable (CSV) Files. Describes the format and content
of the EPAM 5-minute and 12-second CSV data files. Please read this document carefully before attempting to work
with these data. Note that the geometric factors and energy pass-bands in this document must be
used to convert the count-rate data into fluxes.
See also these docs, maintained by Fundamental Technologies, LLC.
The data are publication quality, subject to the same usage rules and warnings
about observational characteristics of the instrument and spacecraft as
regular EPAM Level 2 data.
Release notes for EPAM level 2 data - provided by the EPAM instrument team.
All users of EPAM data should read these notes.
Note on Computing Uncertainties
IN the CSV files there are counting rates for each channel, each sector, so that the best way
to estimate the counting statistical uncertainty is evaluate the number of
counts as 300*rate (c/sec) for the five minute averages. Then one may use
the number of counts in whatever approximate for the statistic that suits
the purpose. This assumes a 100% duty cycle, which isn't exactly true, but
it's almost true. At least this works to ESTIMATE the uncertainty. If the
channel in question happens to be presented in flux units it's still
possible to get the uncertainties. In this case, one has to compute the
rate first by multiplying the flux by the geometrical factor and passband.
The document that I have attached has all of these numbers conveniently
(From Tom Armstrong, Fundamental Technologies, LLC.)
The EPAM Instrument
The Electron, Proton, and Alpha Monitor (EPAM) is composed of five telescope apertures of
three different types. Two Low Energy Foil Spectrometers (LEFS) measure the flux and direction
of electrons above 30 keV (geometry factor = 0.397 cm2*sr), two Low Energy Magnetic
Spectrometers (LEMS) measure the flux and direction of ions greater than 50 keV
(geometry factor = 0.48 cm2*sr), and the Composition Aperture (CA) measures the elemental
composition of the ions (geometry factor = 0.24 cm2*sr). The telescopes use the spin of the
spacecraft to sweep the full sky. Solid-state detectors are used to measure the energy and
composition of the incoming particles.
For more information about the EPAM instrument, visit the
EPAM Home Page, at JHU/APL.
Data contributed by the ACE EPAM team and
Fundamental Technologies, LLC
Contributed Data Page
Return to ASC Home Page
Last modified: Oct 15 2003