TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  93
SUBJECT: BATSE on-board GRB trigger change
DATE:    98/06/01 18:35:57 GMT
FROM:    R Marc Kippen at BATSE/UAH/MSFC  <marc.kippen@msfc.nasa.gov>

RE:    BATSE on-board trigger changes

The BATSE on-board transient event trigger energy range was changed
from channels 3+4 (>100 keV) to channels 1+2 (~20-100 keV) on 31 May,
1998 18:47:38 UT.  The revised trigger definition will be enabled for
approximately two weeks to increase the chance of detecting oubursts
from an active Soft Gamma Repeater (SGR) source.  At the end of this
interval the trigger will be returned to its previous state of using
channels 3+4.  The new trigger setting may result in an unacceptable
number of solar flare triggers, in which case some detectors would be
excluded from the on-board trigger algorithm.  We hesitate to
implement the later, since it leads to very anisotropic trigger
exposure.