Quick Start Guide

This video will help you familiarize yourself with using the utility menu on the Radiation Alert® SEI Inspector USB family of handheld digital radiation detectors.

The SEI Inspector uses a Geiger-Mueller tube to detect radiation. The Geiger tube generates a pulse of electrical current each time radiation passes through the halogen quenched tube and causes ionization. Each pulse is electronically detected and registers as a count. The SEI Inspector displays the counts in the mode you choose.


  • CAUTION: Never touch the SEI Inspector to a surface that may be contaminated. You may contaminate the instrument.
  • Do not leave the SEI Inspector in temperatures over 100° F (38° C) or in direct sunlight for extended periods of time.
  • Do not get the Inspector wet. Water can damage the circuitry and the mica surface of the Geiger tube.
  • Do not put the Inspector in a microwave oven. It cannot measure microwaves, and you may damage it or the oven.
  • This instrument may be sensitive to and may not operate properly in radio frequency, microwave, electrostatic, and electromagnetic fields.
  • If you do not expect to use the SEI Inspector for longer than one month, remove the battery to avoid damage from battery corrosion. Change the battery promptly when the battery indicator appears on the display.
  • CAUTION: When using the unit at altitudes higher than 8000 feet (2438.4 meters), it is possible that the tube window can rupture.