E-PERM

Welcome to Electret Ion Chamber Technology

Rad Elec's E-PERM System has revolutionized the radon industry with its electret ion chamber technology. Recipient of the American Nuclear Society's prestigious International Radiation Science and Technology Award, these accurate, low-cost environmental monitors have gained acceptance in over 500 laboratories across the U.S. and 30 countries worldwide.
The E-PERM System is the first complete system of instruments for true integrating radon, thoron and associated measurements.

The electret ion chamber is a passive integrating ionization monitor consisting of a very stable electret mounted inside a small chamber made of electrically conducting plastic. The electret, a charged Teflono disk, serves as both a source of the electrostatic field and as a sensor. Radon gas passively diffuses into the chamber through filtered inlets, and the alpha particles emitted by the decay process ionize air molecules. Ions produced inside the chamber are collected onto the electret, causing a reduction of its surface charge. The reduction in charge is a function of the total ionization during a specific monitoring period and the specific chamber volume. This change in voltage is measured with Rad Elec's user-friendly
SPER-1 or SPER-2 Electret Voltage Readers.