High performance measurement system of large area solid-state track detector array for ultra heavy cosmic rays

In the handling of solid-state track detector (SSTD), a long period and many human powers has been historically required for a long period and many human powers to scan and analyze etch pits produced on the detector. Because a large area greater than a few m2 detector is required to observe ultra heavy nuclei in galactic cosmic rays, a high speed scanning system is practically important to realize the analysis of our observation data. The apparatus to locate quickly the position of UH event produced in the large SSTD using optical methods was developed, and it allows us effectively to trace incident particle trajectory in cosmic ray detector telescope. We have developed the fast automated digital imaging optical microscope (HSP-1000) to scan and analyze the etch pit produced on the detector, whose image acquisition speed is 50-100 times faster than conventional microscope system. Furthermore, analyzing massive cosmic ray track data produced in extremely large exposed area requires a completely automated multi-sample scanning system. The developed automated system consists of a modified HSP-1000 microscope for image acquisition, a robot arm to replace the sample trays, a magazine station for storing sample trays, and a scanning and analyzing computer to control the whole system. Moreover, since the thickness measurement accuracy in local area of SSTD was improved to achieve high charge and mass resolutions, the new system has been developed to measure the SSTD thickness located adjacent to etch pit in SSTD with an excellent resolution of ± 0.2 m.