Towards a Portable High-Resolution Muon Detector Based on Resistive Plate Chambers (RPCs)

Abstract

The use of conventional imaging techniques becomes problematic when faced with challenging logistics
and confined environments. In particular, such scenarios are not unusual in the field of archaeological and
mining explorations as well as for nuclear waste characterization. For these applications, even the use of
muography is complicated since the detectors have to be deployed in difficult areas with limited room
for instrumentation, e.g., narrow tunnels. To address this limitation, we have developed a portable muon
detector (muoscope) based on glass Resistive Plate Chambers (RPC) with an active area of 16 × 16 cm2.
The specific design goals taken into consideration while developing our first prototype are portability, robustness, autonomy, versatility, safety, and low cost. After gaining building and operating experience withthe first prototype, we are currently in the process of developing an improved second prototype. In line
with our design goals, we also study the possibility of switching the sensitive units from strips in the old
prototype to pixels for the new one. This will help further improve our design goal of portability by reducing the overall weight of the setup by half since a single RPC layer provides bidimensional information
with pixels. However, for performing high-resolution muography, the number of readout units per layer
will also need to increase significantly, leading to an increase in the overall cost and power consumption
of the muoscope. To mitigate these issues, we are developing a novel 2D multiplexing algorithm for reading out several pixels with a single electronic channel. In this article, we give an overview of the detector
development, focusing mainly on the design goals and the choice of detector technology. Furthermore, we
present the details of the expected changes in the new prototype as well as a simulated 2D multiplexing
study based on general principles.