ACE Electron Proton Alpha Monitor (EPAM) Data Products Provided by Fundamental Technologies, LLC

The ACE Science Center provides spin-averaged EPAM fluxes (intensities) at 5-minute, hourly, and daily cadences as standard ACE EPAM Level 2 Data Products.

A more comprehensive set of EPAM data products is provided by Fundamental Technologies, LLC (FunTech).

The data references above 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.

Notes on the comma-separated-variable (CSV) ASCII files provided by Fundamental Technologies, LLC

The data in the rates CSV files consist of count rates of solar ions and electrons, including both sectored and unsectored rates.

Explanation of EPAM Comma Separated Variable (CSV) Files. This document 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.

Note on Computing Uncertainties in Rates and Flux data

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 to 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 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

Last Updated: 19 Dec 2013