Design Study of an Underground Detector for Measurements of the Differential Muon Flux

Bogdan Mitrica

doi:10.1155/2013/641584

Abstract

Since 2006 an underground laboratory is in operation in Unirea salt mine from Slanic Prahova Romania. A new rotatable detector for measurements of the directional variation of the muon flux has been designed and will be put in operation at the end of 2013. The detector will be used to investigate the possible presence of unknown cavities in the salt ore. Preliminary muon flux measurements performed in the underground of Slanic Prahova salt mine show an important variation of the flux with the thickness of the rock but indicate also that more precise data are necessary. Based on that, a modern detector using 4 layers of plastic scintillators bars has been designed. The detector is installed on a rotatable and mobile frame which allows precise directional measurements of the muon flux on different locations in the mine. In order to investigate the performances of the detector, detailed Monte Carlo simulations have been performed using several codes available on the market. The simulations show that the detector can be used for measurements of the differential flux of cosmic ray muons and for the detection of hidden cavities in the ore.

Highlights

During the last decade, a number of events implying collapsed cavities have been observed all over the world [1, 2]
Preliminary muon flux measurements performed in the underground of Slanic Prahova salt mine show an important variation of the flux with the thickness of the rock but indicate that more precise data are necessary
In this paper we report about the design and construction of an underground muon detector that could be used to detect unknown cavities in different areas with mining activity

Summary

Introduction

A number of events implying collapsed cavities have been observed all over the world [1, 2]. The ultrasounds could affect the stability of the rocks, and the gamma and X-rays could produce important changes in the radioactive background of the investigated area Another problem of these methods is represented by the relative high cost of the detectors and of the services. It is evident that the flux of atmospheric muons is a quantity of high interest and information which characterizes the site of a nuclear physics laboratory which is planned for far-reaching investigations Another reason for measuring the flux of the atmospheric muons in the underground arises from the practical necessity of information on the cosmic radiation background for different sites, for experiments like [14, 15], and so forth. The simulations are controlled by muon flux measurements performed with the mobile muon detector of IFIN-HH [20, 21]

Measurements of the Muon Flux in the Underground

The New Rotatable Detector

Simulation of the Detector’s Performances

Useful area

Findings

Conclusions