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High efficiency development procedures for nuclear emulsions *
Author(s) -
Rechenmann R. V.,
Wittendorp E.
Publication year - 1972
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1972.tb04659.x
Subject(s) - emulsion , scanning electron microscope , homogeneous , latent image , materials science , particle size , particle (ecology) , nanotechnology , chemistry , analytical chemistry (journal) , chemical engineering , physics , chromatography , composite material , computer science , thermodynamics , organic chemistry , image (mathematics) , oceanography , artificial intelligence , engineering , geology
SUMMARY The development procedure of nuclear emulsions has been submitted to a systematic study. Each factor involved in this complex procedure has been considered separately. The optimum development time is determined by the maximum of the signal/noise ratio curve. It depends strongly on the other parameters involved in the developing process: temperature, type of emulsion, radiation, developer, etc. New treatment procedures for nuclear emulsions have been established. They are based on the following additional hypothesis concerning the corpuscular latent image: the image formed in the microcrystals consists partly of stable sub‐specks which are not developable, even by total developers. These sub‐germs would render the microcrystals developable if they are ‘activated’, i.e. if their electron levels are lowered by physical or physico‐chemical means. Activation by gold combined with a forced chemical development has proven to give results which are highly reproducible and homogeneous throughout the emulsion layer. Whatever the type of emulsion used and for most chemical developers, this procedure results always in a strong increase in the number of grains developed together with a remarkable stability of the chemical fog. The intensification effect increases when the grain size, the sensitivity of the emulsions and the mean energy released in a grain by a charged particle decreases. The amplification effect becomes more important when the redox potential of the developer diminishes (in absolute value). In light and electron microscope autoradiography, the gain in efficiency resulting from these studies permits the amount of radio‐elements used or the exposure times to be reduced in a ratio varying from 1/5 to 1/20, if compared with classical methods. Moreover, the increased probability of development of the ‘first grain hit’ results in a better resolution.