BATSE	GBM
TOTAL MASS	850 kg	115 kg
TRIGGER THRESHOLD	~0.2 ph/cm2/s	0.61 ph/cm2/s (true threshold)
TELEMETRY RATE	3.55 kbps	15 - 25 kbps
	Large Area Detectors	Low-Energy Detectors
Material	NaI	NaI
Number	8	12
Area	2025 cm2	126 cm2
Thickness	1.27 cm	1.27 cm
Energy range	25 keV to 1.8 MeV	8 keV to 1 MeV
	Spectroscopy Detectors	High-Energy Detectors
Material	NaI	BGO
Number	8	2
Area	126 cm2	126 cm2
Thickness	7.62 cm	12.7 cm
Energy range	30 keV to 10 MeV	150 keV to 40 MeV

PARAMETER	REQUIREMENT	GOAL	CURRENT CAPABILITY
Energy Range	10 keV -- 25 MeV	5 keV -- 30 MeV	~ 8 keV -- 30 MeV
Energy Resolution	20% FWHM at 511 keV	(no stated goal)	12% FWHM at 511 keV
Time resolution	10 μsec	2 μsec	2 μsec
On-board GRB Locations	15 o accuracy (1 σ radius) within 2 sec	10 o within 1 sec	<15 o in 1.8 sec (<8 o for S/C < 60 o zenith)
Rapid ground GRB Locations	5 o accuracy (1 σ radius) within 5 sec	3 o within 1 sec	TBD by analysis (scattering influenced)
Final GRB Locations	3 o accuracy (1 σ radius) within 1 day	(no stated goal)	TBD by analysis (scattering influenced)
GRB sensitivity (on ground)	0.5 photons cm2s-1 (peak flux, 50--300 keV)	0.3 photons cm2s-1 (peak flux, 50--300 keV)	~0.4 photons cm2s-1 (peak flux, 50--300 keV)
GRB on-board trigger sensitivity (50% efficiency)	1.0 photons cm2s-1 (peak flux, 50--300 keV)	0.75 photons cm2s-1 (peak flux, 50--300 keV)	0.71 photons cm2s-1 (peak flux, 50--300 keV
Field of view	8 steradians	10 steradians	9.5 steradians
Deadtime	<10 μsec/count	<3 μsec/count	<2 μsec/count