Thursday, October 4, 2018, 16:00
WHGA Auditorium
Sebastien Procureur, CEA
Abstract:
Muography is an imaging technique making use of natural cosmic muons to
probe the inside of objects. These muons originate from the interaction
of primary cosmic rays with the Earth atmosphere. Their large energy
spectrum allows them to penetrate from a few meters to several hundred
meters of stones, and their interactions with matter provide hints of
its density distribution. Depending on the size of the object this
distribution can be obtained by measuring either the angular deviation
of muons or the absorption/transmission factors in different
directions. The main difficulty of muography is to cope with a modest
muon flux, and therefore to build large area but precise and robust
instruments. Following the R&D made on gaseous, Micromegas detectors
for nuclear and particle physics, we have built at CEA/Irfu six
high-resolution muography instruments over the last three years. Three
of them were deployed around the Khufu's Pyramid in Egypt, within the
ScanPyramids mission. In spite of extreme environmental conditions
(temperature, dust, storms) the telescopes showed good performance and
stability. After the discovery of a first cavity in 2016 on the
North-East edge of the Pyramid, they participated in 2017 to the
discovery of the "ScanPyamids Big Void". This detection is the first
ever of a deep structure of a pyramid from outside, and opens many more
applications of HD muography in the coming years.