Continuum background in space-borne gamma-ray detectors

Instrumental backgrounds present a basic limitation to the sensitivity for any gamma-ray detector. This background consists of both discrete lines and a continuum. The discrete background lines are especially important if they occur at the same energies as the lines of interest needed to meet the science objectives of the mission. The continuum background imposes a limit on the signal to noise ratio that can be achieved. Measurements of the gamma-ray continuum background made during the cruise portion of a number of planetary missions are compared. All of these missions used shields to reduce the continuum background. Measurements made during spaceflight can be used to test the effectiveness of different shield designs.