Extra-large crystal emulsion detectors for future large-scale experiments

Abstract

Photographic emulsion is a particle tracking device which features the best spatial resolution among particle detectors. For certain applications, for example muon radiography, largescale detectors are required. Therefore, a huge surface has to be analyzed by means of automated optical microscopes. An improvement of the readout speed is then a crucial point to make these applications possible and the availability of a new type of photographic emulsions featuring crystals of larger size is a way to pursue this program. This would allow a lower magnification for the microscopes, a consequent larger field of view resulting in a faster data analysis. In this framework, we developed new kinds of emulsion detectors with a crystal size of 600-1000 nm, namely 3-5 times larger than conventional ones, allowing a 25 times faster data readout. The new photographic emulsions have shown a sufficient sensitivity and a good signal to noise ratio. The proposed development opens the way to future large-scale applications of the technology, e.g. 3D imaging of glacier bedrocks or future neutrino experiments.

Nuclear Emulsions

“…The production of new types of emulsions with crystal sizes of 600-1000 nm, 3-5 times larger than those of standard films, has been studied and realised using the gel production machine at Nagoya University. The first results characterising newly produced emulsions have been reported [126], showing a sufficient sensitivity and a good signal to noise ratio (Fig. 9.18).…”

“…Right: Tracks of Kr ions in such an emulsion, as seen with a scanning electron microscope Fig. 9.18 Electron microscope pictures of silver halide crystals (left) and electron tracks (right) in a conventional film and in the newly developed samples [126] oscillation experiments mentioned above was 200 nm and has never been larger than 300 nm in previous experiments. The production of new types of emulsions with crystal sizes of 600-1000 nm, 3-5 times larger than those of standard films, has been studied and realised using the gel production machine at Nagoya University.…”

Muon Radiography Method for Non-Invasive Probing an Archaeological Site in the Naryn-Kala Citadel

“…Currently, in experiments conducted using the method of muon radiography, both electronic and emulsion track detectors are used. Emulsion detectors [11,12] have a number of advantages, with the main one being a high angular resolution. Of all the muon radiography detectors, the emulsion ones have the best angular resolution.…”

Latest nuclear emulsion technology

“…Recently, we produced various-sized crystals according to the purposes of experiments. The minimum-sized crystals (the diameter is 30-40 nm) are being developed for dark matter directional searches [6], and the maximum-sized crystals (∼800 nm) for the long term observation requesting the stability of the latent image [7]. The environment of the mass production of films is constructed in the laboratory.…”