The Fermi GBM instrument consists of twelve NaI detectors pointing in various directions, and two BGO detectors pointing in opposite directions. The NaI detectors measure the low-energy spectrum from 8 keV (nominally, see Note 1 below) to 1 MeV; the BGO detectors cover the higher range of ~200 keV to ~40 MeV. The GBM NaI and BGO data are available in two forms:
There are daily files and trigger files (burst and surrounding data) for each
detector. NaI detectors are labeled n0 through nb; BGO detectors are
labeled b0 and b1. n0 through n5 are usually the sunward NaI detectors
(with constantly changing angles), and b0 is always the sunward BGO detector.
The Fermi LAT instrument observes gamma-rays above ~20 MeV. The LAT spectrum and response files must be requested from the LAT team.
On a daily basis, we scan the GBM data for solar flares, compile a solar flare list, and generate daily and orbital quicklook plots (most easily viewable through the RHESSI Browser link below). For each flare identified, we also generate a GBM response matrix file.
OSPEX, our IDL spectral analysis package, is used to view the count-rate data as a function of time or energy, as well as to convert the count-rate data into the spectrum of the incident photons using various selectable spectral forms. Input to OSPEX are the daily or trigger count-rate data file (GBM CSPEC or CTIME, or LAT) and the corresponding detector response matrix file.
Note 1: In order to reduce count rates during periods of high solar activity, the low energy threshold of the sunward NaI detectors is raised periodically. Please see the LLT Settings Table.
Reports and Presentations for this Proposal Effort:
Last updated 22 October, 2012 by Kim Tolbert