Connect the sensor following the steps in the Getting Started section of this user manual.
The ɑβɣ LED will flash for each alpha, beta, or gamma particle detected. Turn on/off the optional audio signal using the small switch on the base of the box, next to the GM tube.
To measure gamma and X-rays, hold the tip of Go Direct Radiation Monitor toward the source of radiation. Low-energy gamma radiation (10–40 keV) cannot penetrate the side of the GM tube, but may be detected through the end window.
To detect alpha radiation, position the monitor so the suspected source of radiation is next to the GM window. Alpha radiation will not travel far through air, so put the source as close as possible (within 1/4") to the screen without touching it. Even a humid day can limit the already short distance an alpha particle can travel.
To detect beta radiation, point the end window toward the source of radiation. Beta radiation has a longer range through air than alpha particles, but can usually be shielded (e.g., by a few millimeters of aluminum). High energy beta particles may be monitored through the back of the case.
To determine whether radiation is alpha, beta, or gamma, hold the tip of the monitor toward the specimen. If there is an indication of radioactivity, it is most likely gamma or high energy beta. Place a piece of aluminum about 3 mm (1/8") thick between the case and the specimen. If the indication stops, the radiation is most likely beta. (To some degree, most common radioactive isotopes emit both beta and gamma radiation.) If there is no indication through the back of the case, position the end window close to, but not touching, the specimen. If there is an indication, it is probably alpha or beta. If a sheet of paper is placed between the window, and the indication stops, the radiation is most likely alpha. In order to avoid particles falling into the instrument, do not hold the specimen directly above the end window.
The Radiation Monitor does not detect neutron, microwave, radio frequency (RF), laser, infrared, or ultraviolet radiation. Some isotopes it will detect relatively well are cesium-137, cobalt-60, technicium-99m, phosphorus-32, and strontium-90.
Some types of radiation are very difficult or impossible for this GM tube to detect. Beta emissions from tritium are too weak to detect using the Radiation Monitor. Americium-241, used in some smoke detectors, can overexcite the GM tube and give an indication of a higher level of radiation than is actually present.
Click or tap the view icon and select Meter. The instantaneous sensor readings are all displayed. Click or tap any meter to zero or calibrate that sensor.
Click or tap the view icon and choose the number of graphs you wish to display. For each graph, click or tap on the y-axis label to select which sensor data you would like displayed on that graph. Change data-collection parameters (duration, sampling rate) by clicking or tapping on graph options. When ready to collect data, click or tap collect.