EMULSION STACK

The objective of the flight was to expose to cosmic radiation a stack of nuclear emulsions. As the heavy nuclei in the cosmic radiation with charges equal to or greater than that of lithium are rapidly absorbed in the atmosphere by nuclear interactions, in order to study these nuclei is needed to place the detecting equipment as high in the atmosphere as possible. To do so, a series of stratospheric balloon flights were performed above northern Italy in the decade of 1950 through a collaboration between the universities of Milano and Padua for the Italian side and Bristol University from England.

This particular flight was carried out from Biella in the Piedmont region on October 14th, 1954. The payload was a stack composed by 80 stripped sheets of Ilford G5 emulsions, 20 cm long, 15 cm wide and 600µ thick. After launched the balloon ascended to a float altitude of 105.000 feet moving across the Marittime Alps and entering in French airspace. The presence of the balloon in french skies caused quite a conmmotion in the population of several towns that believed they were seeing an UFO. Even the astronomical observatory of Haute-Provence was able to obtain pictures of the balloon (image at right). The payload apparently landed near Briancon, in France, causing some diplomatic problems during the recovery. The scientific Italian team contacted their colleagues from the Ecole Politechnique who finally convinced the French police to spread the news, and the load was eventually found.

During the flight the emulsions were exposed for 5 hours and 40 minutes at a mean altitude of 35 km, steadily at a geomagnetic latitude of 46º north. The heavy nuclei of the primary cosmic radiation produced a total of 317 nuclear interactions which were registered in the emulsion stack.

Balloon launched on: 10/14/1954
Launch site: Biella, Piedmont, Italy  
Balloon launched by: University of Milan
Balloon manufacturer/size/composition: Zero Pressure Balloon  
End of flight (L for landing time, W for last contact, otherwise termination time): 10/14/1954
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): F 5 h 40 m
Landing site: Near Briancon, France

• 14-15-16 octobre 1954, près de Digne-les-Bains, Alpes-de-Haute-Provence UFOs at close sight website
• Further interactions of the heavy nuclei of the cosmic radiation Philosophical Magazine, 3:25, 19 (1958)
• Interactions of the heavy nuclei of the cosmic radiation Philosophical Magazine 2 (15):293-304 (1957)
• L'histoire du dimanche� Alerte aux soucoupes volantes ! Le Dauphiné Libéré, France 8/11/2019
• LXIV. The energy distribution of cosmic ray particles over northern italy Philosophical Magazine, 1:7, 637 (1956)
• Observation d'un ballon-sonde à l'observatoire de Haute-Provence L'Astronomie, Vol. 68, p.416