Trade.Information

Product Name: ENVIRONMENTAL AND WORK PLACE GAMMA RADIATION

Product Description

System: Electret Ion Chamber 
Lab/Field: Field (In situ measurements) 
Radiation detected: Gamma Radiation 

Operation 

This system is a passive integrating detector system for field measurement of X or gamma radiation. It consists of a charged Teflon disk(electret), an ionization chamber, and electret voltage reader and optional data logger. When the electret is screwed into the chamber, a static electrostatic field is established and a passive ionization chamber is formed. The chamber is deployed directly at any location where average gamma radiation needs to be measured over a desired time interval. The gamma radiation penetrates 2 mm thick electrically conducting plastic body of the chamber and ionizes the air molecules; the ions are attracted to the charged surface of the electret, and the electret charge originally present gets reduced. The electret charge is measured before and after the exposure with a portable electret voltage reader, and the rate of change of the charge(change divided by the time of exposure) is proportional to the average gamma radiation level presented to the detector. Electret ion chambers(electret +chamber) are inexpensive, simple, passive, with no moving parts or electronic components, unaffected by ambient environmental conditions and can be normally used for several measurements before a need for replacement of the electret. The detectors are sealed in a Mylar bag to prevent ambient radon from entering the air phase of the detector. 

Specificity/Sensitivity: 

This method measures gross gamma radiation. Electret ion chambers (EIC) provide energy independent tissue equivalent response for X and gamma radiation of energies above 15 KeV. EICs do not require fading corrections. Lower limit of detection depends upon the exposure time and the volume of the chamber used. For measuring ambient levels of about 10 microR/h, a 50 ml chamber needs to be deployed for 30 days and a 1000 ml chamber needs to be deployed for about 2 days. A 50 ml chamber is usable for long term monitoring requiring monthly or quarterly measurements. 
Applicability for Site Clean up 

Several hundreds of the detectors can be deployed and analyzed at a time using one measuring/analyzing instrument. 

Cost
Cost of Equipment: $ 4000 to $ 10000 
Consumable cost of detector per measurement:Under $1 
Measurement applications include :
Compliance with Nuclear Regulatory Commission and State regulations for perimeter monitoring 
Qualifying measurements for free release of contaminated sites
Monitoring pre and post decommissioning and decontamination of nuclear facilities

Company Details

Rad Elec Inc (REI) was incorporated in 1987 to manufacture and commercialize a product researched and developed under a research contract with NYSERDA (New York Energy Research and Development Authority) during 1986 -1987. The product was based on... more