Monitoring of short-lived radon progeny in mines

Abstract

Obligatory measurements of the potential alpha energy concentration of short-lived radon progeny have been performing in the Polish underground mines since 1989. In consideration of economic aspects, an attempt was made from the very beginning to combine it with measurements of the dust concentration. Therefore the developed measuring units were an integral part of the dust samplers complying with the requirements of the State Mining Authority to apply them in underground mines. This way the developed devices could fulfil two measurement tasks simultaneously: measurement of the dust concentration and potential alpha energy concentration of short-lived radon progeny. The new device based on the thermoluminescence detectors is able to cooperate with the dust samplers made by the SKC company and equipped with a cyclone making it possible to operate them constantly for one working day. The lower limit of detection was equal about 0.04 microJ m(-3) at a 95% confidence level and 1 h pumping.

Influence of Dose Conversions, Equilibrium Factors, and Unattached Fractions on Radon Risk Assessment in Operating and Show Underground Mines

“…The aspirators are powered by rechargeable batteries and can run for up to eight hours. After exposure, the thermoluminescent detectors are read out using dedicated thermoluminescent readers to assess the alpha potential energy concentration [ 24 ]. The AlphaGuard-EF radiometer (Genitron, Frankfurt, Germany; Bertin Technologies, Montigny-le-Bretonneux, France) is designed for long-term measurements of radon activity concentration in air.…”

“…The aspirators are powered by rechargeable batteries and can run for up to eight hours. After exposure, the thermoluminescent detectors are read out using dedicated thermoluminescent readers to assess the alpha potential energy concentration [ 24 ].…”

A method for the simultaneous measurement of radon and thoron PAEC concentrations in air using a TLD monitor

“…The method was based on the filtration of the air through the filter, above which a holder with the TLD was positioned (figure 3). During air sampling and afterwards, the decay of radon descendant nuclides leads to the emission of alpha particles and the irradiation of the TLDs (Skubacz and Bywalec 2003). During air sampling, the ALFA probe is placed in a microcyclone to remove the non-respirable fraction of aerosols from the air and, as a result only the respirable fraction is deposited on the filter.…”

“…In 1989, a decree of the Ministry of Mining and Power Generation enforced the use of these monitors (called ALFA sampling probes) in all underground mines in Poland (decree 1988). Due to the use of the usual dust sampler, it was possible to measure the dust concentration and the PAEC simultaneously (Skubacz and Bywalec 2003). The energy of the alpha particles is registered by the thermoluminescent detectors, therefore, the readout of the TLD is related to the potential alpha energy of radon (and thoron) decay products, with no dependence on the equilibrium factor between radon isotopes and their decay products, dust content, humidity or other parameters of the air.…”

“…The detection limit of this method (LLD) is very important-the most important factors are the flow rate through the filter and the sampling time. In mines, with the use of a dust sampler with a flow rate of 2.2 l min −1 and a nitrocellulose membrane filter with a diameter of 18 mm, it was possible to achieve an LLD of the order of 0.01 µJ m −3 for a sampling time of 8 h for the radon PAEC as well as the thoron PAEC (Skubacz and Bywalec 2003, Currie 1968, ISO 2005.…”