Advances in Thick GEM-like (THGEM) multipliers

The concept and properties of the novel and robust Thick GEM-like (THGEM) hole-multiplier, economically produced by standard printed-circuit techniques, is presented. It has a GEM-like structure and operation mode, with dimensions expended to the sub-mm to mm scales, and mechanically-drilled holes etched at their rim. Very high electron multiplication, 10$^{5}$ and 10$^{7}$ in single- and double-THGEM elements were reached; very efficient electron transport into and out of the holes permits efficient multi-element cascading. The fast avalanche buildup leads to ns timing properties and rates exceeding MHz/mm$^{2}$. The THGEM can efficiently detect single gas-ionization electrons or radiation-induced electrons from a solid converter -- e.g. a photocathode deposited on its top surface. The former is important for particle tracking, x-ray imaging etc, and the latter has important applications in photon and neutron imaging. The results of recent studies will be presented, including sub-mm imaging properties of a 100x100 mm$^{2}$ detector prototype. Potential applications will be discussed: UV-photon imaging in RICH, moderate-resolution tracking, TPC read out, sampling elements in calorimetry, x-ray and neutron imaging, charge and light detection in 2-phase noble-liquid detectors etc.