In fact, many SCIONIX
scintillation detectors are custom-made with detector configuration and materials adapted
to the specific requirements of the user. Regarding the special applications we would like
to mention here anti-Compton
shields, scintillation
detectors with
miniature PMTs and phoswiches.
ANTI-COMPTON
SHIELDS
Anti-Compton (AC) systems are
scintillation detector assemblies mounted around a High Purity Ge-detector (HPGe) that
detect the gamma rays Compton scattered by the Ge crystal and generate a veto signalwhen
such a Compton event occurs. This improves the peak-to-total ratio in the pulse height
spectrum of the Ge detector significantly.
Crucial parameters are a large solid
angle coverage around the HPGe detector and high stopping power. The use of segmented
well-type BGO detectors is the generally accepted optimum approach, except for low
background systems where the intrinsic high background of BGO is prohibitive and NaI(Tl)
is normally used. Below some examples are shown.
AC-shields can be provided with
special backcatcher detectors around the cryostat arm for optimum solid angle coverage. To
save cost, BGO AC-shields are often equipped with a NaI(Tl) "nose" since at
these angles scattered energies are low and a high stopping power is not required.
Many options are possible and we
advise to contact SCIONIX to discuss the optimum AC shield configuration for your Ge
detector assembly. |