P. Vojtyla, INFLUENCE OF SHIELD PARAMETERS ON COSMIC-MUON INDUCED BACKGROUNDS OF GE GAMMA-SPECTROMETERS, Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms, 111(1-2), 1996, pp. 163-170
Computer simulations using GEANT 3.21 with shields of various paramete
rs are performed to investigate how shield parameters can influence th
e cosmic-muon induced background of a typical low-level HPGe gamma-spe
ctrometric system. It was found that the background increases with inc
reasing inner shield dimensions to reach a saturated value for very la
rge dimensions when the composition of the shield (bulk material, thic
kness, lining and proportion between height and width) is not changed.
The background for a large shield is almost twice that for a tight on
e. The background does not depend significantly on the position of the
detector inside a shield and on the shape (cylinder or rectangular) p
rovided the inner dimensions are the same. There is a strong dependenc
e on bulk material and lining. Backgrounds are lower below approximate
to 500 keV but higher above approximate to 500 keV and in the 511 keV
annihilation peak for higher-Z materials. Several types of lining are
simulated and compared. Best results are obtained for a lead shield l
ined with 2 mm of tin.