Trade.Information

Product Name: Radon Flux from Mill Tailings, Phosphate Stacks & Ground

Product Description

System: Electret Ion Chamber 
Lab/Field: Field (In situ measurement ) 
Radiation detected : Radon flux from ground, phosphate stacks, uranium mill tailings 

Introduction

The passive measurement of radon flux from the ground is useful for 
predicting indoor radon potential of a building site 
to meet the regulatory requirement of radon emanation from the uranium mill tailings, phosphate stacks, copper and gold mill tailings 
evaluating radon potential of building materials. U. S. EPA limit for radon flux is 20 pCi per m2 per sec.
Operation 

The flux monitors make use of the principle of electret ion chambers. This system is a passive integrating detector system for measurement of radon. It consists of a charged Teflon disk(electret), open faced ionization chamber, and electret voltage reader and data logger. When the electret is screwed into the chamber, a static electrostatic field is established and a passive ionization chamber is formed. When the ions are brought into such a chamber by the fast moving air flow through an alpha contaminated pipe, 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 radon flux. 

The passive flux monitor consists of a one liter volume chamber with carbon coated Tyvek window with filtered vents. When it is positioned on the surface being tested, the radon from the ground enters the chamber through the window and exits through the vents. The semi-equilibrium radon concentration established inside the chamber is representative of dynamic radon flux from the surface. Because of the equilibrium between the surface and outside environment through the vents, the flux emanation from the surface is not disturbed. The electret discharge rate is a measure of the undisturbed radon flux. These flux monitors are calibrated by exposing them on a well characterized standard flux beds available at CANMET, Canada. 

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. 
Specificity/Sensitivity 

This system measures radon flux. Lower limit of detection is 0.24 pCi per m2 per sec when measured over 8 hours and 0.08 pCi per m2 per sec when measured over one day. It is possible to measure still lower values by measuring over a longer periods. 
Applicability for Site Clean up: 

When uranium/radium contaminated soil/ arising out of a decontamination efforts, such soil can be evaluated for radon flux before deployment elsewhere. If such soil has already been used, the radon flux measurement is useful if further mitigation need to be done. The flux is also an indication of radium contamination. Several hundreds flux monitors are usable at different sites or at different location on the same at a time and analyzed at a time using one measuring/analyzing equipment. 
Cost 

Cost of Equipment: $ 5000

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