[en] Autoradiography is a widely used technique in pharmacology and biological fields. It is able to localize in 2 dimensions molecules labeled with beta emitters. The gaseous detector incorporating micromesh Parallel Ionization Multiplier (PIM) has already shown its ability to localize precisely electrons from low-energy emitters like ³H and ¹⁴C with a high resolution or on a large area. We report on a new prototype devoted to precise determination of beta emitters. It could be used to image gamma emitters distribution by using autoradiography of the associated beta particles present on a large number of useful gamma radioelements such as ¹³¹I, ⁴⁶Sc, ¹⁸F, etc. By proceeding with a dedicated method, we expect to locate in 2 dimensions the position of gamma emitter with a precision greater than 150 μm. This new prototype could also be used for traditional low-energy beta autoradiography of ³H, ¹⁴C or ¹²⁵I with a spatial resolution better than 50 μm and real-time imaging. First results obtained with this new prototype are presented.

[en] Gaseous PhotoMultipliers (GPM) are a very promising alternative of vacuum PMTs especially for large-size noble-liquid detectors in the field of Functional Nuclear Medical Imaging and Direct Dark Matter Detection. We present recent characterization results of a Hybrid-GPM made of three Micropattern Gaseous Structures; a Thick Gaseous Electron Multiplier (THGEM), a Parallel Ionization Multiplier (PIM) and a MICROMesh GAseous Structure (MICROMEGAS), operating in Ne/CF₄ (90:10). Gain values close to 10⁷ were recorded in this mixture, with 5.9 keV x-rays at 1100 mbar, both at room temperature and at that of liquid xenon (T=171 K). The results are discussed in term of scintillation detection. While the present multiplier was investigated without photocathode, complementary results of photoextraction from CsI UV-photocathodes are presented in Ne/CH₄ (95:5) and CH₄ in cryogenic conditions.