First demonstration of a roller-driven timestamp mechanism for long-duration observations with high time resolution using large-area emulsion films

Abstract

Abstract A multi-stage shifter allows timestamped measurements by emulsion films, which have a thin medium and high resolution (< 1μm). Using multiple layers of emulsion films that move at different speeds like hands of an analog clock, the shifter can create a unique positional displacement with respect to the time-track recorded. The time information of each track is obtained by reproducing each positional displacement by track reconstruction. We developed a new model of shifter with a lighter structure to enable a large aperture area and long-duration observation times by adding more layers. Operational testing suggested that the new shifter has a sub-second time resolution, which allows an emulsion gamma-ray telescope to obtain an imaging resolution within 1° (> 80 MeV), like previous balloon experiments. Furthermore, by adding a layer which move at 100 μm s-1, it achieved the 0.1 s time resolution required for high-resolution imaging above 1 GeV. We also found the possibilities of an almost three-fold improvement in the spatial resolutions in track reconstruction compared with the conventional model and of achieving time resolution on a scale of tens of milliseconds, which would enable phase resolution of a pulsar.