Development of high-contrast developing for nuclear emulsion film for GRAINE experiment

S. Yamamoto, Y. Isayama, I. Usuda, T. Nakamura, Y. Nakamura, H. Minami,H. Rokujo, M. Nakamura, T. Nakano, S. Aoki, S. Takahashi, S. Nagahara, M. Oda, T. Kato, M. Yamashita, K. Okamoto, S. Yoneno, K. Kodama, K. Nakazawa, A. Iyono, S. Akita and F. Murakami

The GRAINE experiment is the balloon flight experiment with emulsion chamber telescope for observing of gamma rays that have energy range of 10 MeV to 100 GeV. We launched the emulsion chamber telescope in Australia in the April, 2023 (GRAINE2023). GRAINE2023 have the larger aperture area than previous experiments, and the aperture area increase from 0.38 square meters to 2.5 square meters. The nuclear emulsion film is the kind of photographic film, and we can observe emulsion films on the microscope after the development. The scale of experiments with the nuclear emulsion film increases, the Hyper Track Selector (THS) was developed for convert track in the nuclear emulsion film into data at high speed, and have been producing success. Additionally, the HTS2 was developed for improvement of the scanning speed over THS, by lowering the magnification and widening the field of view of the captured image. On the other hand, the THS2 is concerns about the deterioration of the detection performance of developed silver. As one way, to improve the detection performance of developed silver, we changed the developer, which makes enlarge developed silver grains. So far, we have used XAA development, but we made development possible to adjust the size of developed silver grains by mixing chemicals with ourselves. We study and develop of high-contrast developing for the nuclear emulsion film and expand of development scale ,and report the result of developed emulsion films of GRAINE2023.

Proceeding of Science

POS

444

883

1

8

DOI: https://doi.org/10.22323/1.444.0883

https://pos.sissa.it/444/883/pdf