Daily scan for 3He-rich periods in EPHIN PHA data (1996-2016)

The attached file contains an automatic selection of possible 3He-rich days based on SOHO/COSTEP-EPHIN PHA data.  An IDL-based code scanned the whole mission (Jan 1996 to Nov 2016) searching daily-averaged periods with estimated 5-25 MeV/n 3He/4He ratios above 0.04.

Click here to download the file with all the candidate periods

Composition evolution during a 3He-rich SEP event observed by EPHIN on August 19, 2003. The top panel show the counting rates inferred from PHA data. The bottom panels shows the particle id (inferred from PHA data) versus time, with color-coded intensity (the histogram at the right side shows the cumulative composition for the whole interval).


Logarithm of the energy loss in EPHIN top detector vs the total energy of the incoming particles (PHA data with color-coded counting rate). Separate tracks for 3He and 4He are clearly seen in the top part of the plot. The period corresponds to the 3He-rich SEP event shown in the previous figure.