Volume 358 - 36th International Cosmic Ray Conference (ICRC2019) - CRI - Cosmic Ray Indirect
Improvement of cosmic-ray muography for Earth sciences and civil engineering
L. Olah*, H. Tanaka, G. Hamar and D. Varga
Full text: pdf
Pre-published on: July 22, 2019
Published on: July 02, 2021
Abstract
Muography is utilizing the cosmic-ray muons to deduce the amount of material across large-sized objects, similarly to X-raying of human body. We specifically developed Multi-Wire Proportional Chamber (MWPC)-based tracking systems with high ($>$ 98 $\%$) efficiency, fair ($<$ 10 mrad) angular resolution and low ($<$ 6 W) power for Earth sciences and civil engineering. A muography observatory is assembled from trackers on a sensitive surface of 5.5 m$^2$ at 2.8 km distance in South-West from Sakurajima volcano to provide projective density images of the crater regions for future measurements of mass variations occurred during eruptions. An industrial applicability of portable, MWPC-based instruments have been demonstrated with the muographic imaging of an underground iron pillar.

We investigated the limits of muography: the Gaisser model is suggested to be modified with an energy exponent of -2.64 and constant scale factor of 0.66 for imaging in near-horizontal directions after large ($>$ 1,000 m.s.r.e.) thicknesses. The multiple scattering of muons across the targeted object is limiting the imaging resolution from 10 mrad to 5 mrad with the increase of thickness between 50 m.s.r.e. and 2,000 m.s.r.e..

The precise measurement of low-energy muon spectra is required to improve muography of small-sized objects. We developed a 5-meter-length, rotatable, MWPC-based spectrometer to precisely measure the energy spectra of muons between 0.5 GeV and 5 GeV from vertical to horizontal directions. It is a consecutive series of thirteen detectors with a positional resolution of approx. 4 mm and lead plates. The spectrometer and the first results are presented.
DOI: https://doi.org/10.22323/1.358.0377
How to cite

Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in "proceeding" format which is more detailed and complete.

Open Access