TOSCA: A large-area position sensitive detector for sub-nanosecond time-of-flight applications involving charged radiation

A large-area, position-sensitive, passing-through detector unit, named TOSCA ( T ime- O f-flight-sub-nano-second S pectrometer for C harged radiation A pplications), has been developed for use in Time-Of-Flight (TOF) spectrometers. The detector provides simultaneous measurements of timing and two-dimensional impact position of traversing ions by detecting secondary electrons emitted from a thin conversion foil. The electrons are guided by electrostatic optics toward a microchannel plate amplification stage and collected on a pads-and-strips anode integrated into a printed circuit board, replacing conventional wire-based delay-line readout systems. Position resolutions of the order of 1 mm and intrinsic time resolutions better than 100 ps have been achieved when coupled to fast sampling electronics. The passing-through architecture ensures that only electrons reach the microchannel plates, resulting in improved radiation hardness and extended detector lifetime. The use of identical, fully position-sensitive TOSCA units as both Start and Stop detectors removes the functional asymmetry typical of conventional TOF spectrometers and enables multi-point trajectory measurements within a single TOF arm. This approach allows the realization of compact and flexible two-arm TOF spectrometers based on four identical detector modules. In-beam tests with heavy ions demonstrate the performance and potential of the TOSCA concept for high-resolution mass and energy measurements in heavy-ion reaction studies.