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| Titel |
A telescope for rock mass density imaging based on muon TPC* with Micromegas-bulk detector |
| VerfasserIn |
Pierre Salin, Stéphane Gaffet, Ioannis Giomataris, Denis Calvet, Frédéric Druillole, Rui de Oliveira, Olivier Pizzirusso |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250051346
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| Zusammenfassung |
| In the framework of the realization of field telescopes dedicated to the tomography of geological
objects, the choice of proportional detectors parallel plate type MICROMEGAS-Bulk,
compared to scintillating plastic, was motivated by reasons of robustness, lightness and
adaptability to various configurations of measurements. The choice of MICROMEGAS-Bulk
was also necessary for its intrinsic qualities:
The rise and fall times of the pulse measured lower than 1Â ns is sufficiently rapid
to allow determining the direction (azimuths and zeniths) of muons by temporal
discrimination,
The ability to build compact detectors, dedicated to karst galleries and small
section tunnels since only one detector is required to measure the direction of the
muons,
The stability of the gain, adjustable from 1 to about 105,
The printed circuit technique that allows facilitating future developments and
valorizations.
We present the progress of the project T2DM2 (Temporal Tomography of Density by Muons
Measurements) developed by GEOAZUR Lab (http://geoazur.oca.eu) in order to investigate
the properties of the carbonate reservoir surrounding the LSBB underground lab
(http://lsbb.oca.eu).
The aim is to proceed a continuous survey in order quantifying changes in the density of
the carbonate reservoir surrounding the LSBB underground lab (http://lsbb.oca.eu). The goal
is to reach an accuracy of 10-3 for the muon flux that will be sufficient to characterize the
temporal variations of the density associated with the water flow into the massif for depth
ranging from 10Â m to 500Â m depth. The expected changes are greater than 3Â % for the
Urgonian facies of the reservoir whose porosity varies between 10Â % and 20Â %. The
technological configuration of the muon telescope must meet the observational constraints of
exposure duration, angular resolution and surface available to deploy the telescope,
these constraints determining the temporal and spatial resolution of hydrodynamic
processes.
Thus, an angular resolution of 10Ë for a 3Â m2 telescope achieves a well adapted
statistical counting of muons (~Â 1000Â muons) in 40Â days at 500Â m depth for vertical flow
(Φv = 3.10-3 μ m-2 s-1 sr-1 after PDG standard http://pdg.lbl.gov). To a depth of
200Â m, it suffices to deploy a telescope of 1Â m2 to obtain the same accuracy with the same
angular resolution.
TPC *: Time Projection Chamber 3D |
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