A thoron monitor.
D000398:Air Pollution, Radioactive; D000512:Alpha Particles; D004391:Dust; D011834:Radiation Monitoring; D011868:Radioisotopes; D013910:Thorium; D014316:Tritium
D004391:Dust; D011868:Radioisotopes; D014316:Tritium; D013910:Thorium