An active device for radon detection in the air was developed. The monitor operates in pulse counting mode for real-time continuum measurements. The presented prototype has a relatively simple design made of low-price and easy to acquire components which made it possible to develop an inexpensive device. The device uses as sensor the SLCD-61N5 Si-PIN planar photodiode, which has an area of 9.67x9.67 mm 2 , sensitive to alpha particles. An Arduino Uno microcontroller was used as data acquisition system. Signals were observed when placing an 241 Am source near the sensor. The sensor's sensitivity is bias dependent, but the device can operate even at modest voltage. As a result of a one-month test in a rich radon atmosphere, a positive high correlation was obtained between our prototype and a Geiger-Müller detector.

This research presents a design of a resilient blind-tube radiometric logging probe, which satisfies key, operational site constraints, for direct in-situ characterization of subsurface radioactivity, particularly caesium-137 and strontium-90. The probe comprises a commercially-available Ø10 mm × 9.5 mm CeBr3 scintillator detector attached to a compact digitizer unit, in a resistant and waterproof housing. The probe is designed to be lowered down into metallic Ø 75 mm blind-tubes by means of a winch system.