A new type of detector for positron-emission tomography (PET) has been
proposed recently, using a heavy organo-metallic liquid - TriMethyl Bismuth
(TMBi) - as target material. TMBi is a transparent liquid with the high Z
element Bismuth contributing 82% of its mass. 511keV annihilation photons are
converted efficiently into photo-electrons within the detector material
producing both Cherenkov light and free charge carriers in the liquid. While
the optical component enables a fast timing, a charge readout using a segmented
anode can provide an accurate position reconstruction and energy determination.
The charge measurement requires a high level of purification, as any
electronegative contaminants cause signal degradation. In addition to the
purity requirements, the reactive nature of TMBi poses many challenges that
need to be met until a fully functioning detector for PET applications can be
realized. The paper presents an experimental setup that aims to remove
electronegative impurities by electrostatic filtering and to characterise the
properties of TMBi, e.g. the relative permittivity, for its application as a
detector medium for charge read out