Speaker
Description
We are developing an MRPC for imaging the internal structure of volcanoes and estimating soil water content using cosmic-ray muons.
Continuous observations of cosmic-ray muons may contribute to monitoring geophysical mass variations such as volcanic activity and soil moisture changes.
To identify high-energy penetrating muons, time-of-flight information from two MRPC layers is used to suppress background events.
For imaging the internal structure of volcanoes, this MRPC is required to achieve a time resolution better than 70 ps and a position resolution better than 0.2 mm.
A prototype TOF-tracker MRPC has been produced to provide high-precision timing and two-dimensional position measurements.
The detector employs 5-mm-pitch readout strips in two lengths, 500 and 1000 mm.
We have performed a beam test at the SPring-8/LEPS2 beamline and have been conducting a cosmic-ray test.
From these tests, we have evaluated how the time and position resolutions depend on the signal propagation distance along the readout strip and the electrode sheet resistance.
In this presentation, we will report the measured time and position resolutions and discuss the remaining challenges toward achieving the required performance for volcano imaging and soil water content estimation.