Parallel ionization multiplier (PIM): a new concept of gaseous detector for radiation detection improvement

New amplifying structures can be built exploiting the electric properties of metallic meshes a few microns thick. They can be used for preamplification with a variety of gaseous detector or for one-stage amplification. Detection efficiency better than 80% and 50 μm (FWHM) 2D accuracy on A4 sensitive areas, with uncollimated sources of 3H or 14C, is achieved with such preamplifiers. wo amplifying stages, the discharge rate with α sources is reduced by a factor close to 1000 compared to single-stage amplification at equivalent gain values. These results have been obtained on a new structure that has been developed, called PIM for parallel ionization multiplier. PIM is made of a thin sandwich of two metallic meshes separated by a new insulating spacer whose geometrical characteristics are made possible by state-of-the-art developments in laser etching technologies. A drastic improvement has been found in the minimal distance between spacers necessary to keep the distance between the metallic meshes stable.