Trade.Information

Product Name: ALPHA (NORM) CONTAMINATION IN PIPES, TOOLS AND OBJECTS

Product Description

System: Ion Transfer Electret Ion Chamber 
Lab/Field: Field (In situ measurement ) 
Radiation detected : NORM ( naturally occurring radioactive materials) and other alpha emitting isotopes such as plutonium inside pipes, on contaminated tools and other irregularly shaped objects. 

Introduction 

Pipes do get contaminated with naturally occurring alpha emitting radioactive materials such as uranium, thorium, radium and polonium during handling and processing of ores/ minerals of copper, uranium, gold and thorium. Radium scaling build up is comm on in pipes used in petroleum and natural gas oil industry. Such contamination is also found in sewage pipes. These pipes need to be cleared for reuse or far resale or for disposal as a scrap. Similarly there are situations in Nuclear Industry with pipe s contaminated with plutonium and other alpha emitting transuranium elements. The U.S.D.O.E., limits for free release of such materials is 2.2 dpm (0.04 Bq per cm2 ) . The alpha particles have only a range of 4 to 6 cm and the conventional methods of moni toring by locating an alpha detector inside the pipes is not possible. The ions produced by the alpha emitting isotopes is moved out to an electret ion chamber and measured. This method is called as ion transfer method. 
Operation 

This system is a passive integrating detector system for measurement of alpha-emitting contaminants inside the pipes. It consists of a charged Teflon disk(electret), open faced ionization chamber, and electret voltage reader and data logger. When the elec tret 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 alpha activity inside the pipe. 

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 method is a gross alpha measurement. The measurement may be converted to elemental or isotopic concentration ( such as Pu, U or Ra) if the isotopes are known or measured by another method. The lower limit of detection is a function of deployment time: 2000 to 3000 dpm (about 50 Bq) can be detected in 15 minutes. Higher levels are measurable in shorter periods, and still lower levels in longer periods. This method is usable for determining the alpha contamination inside the pipes. A contaminat ion level of 2.2 dpm/cm2 in a pipe, 6 feet long and 2 inch diameter is measurable in 15 minutes. Higher levels are measurable in shorter periods, and still lower levels in longer periods. 
Applicability for Site Clean up 

High contamination levels may be measured with a deployment times of a few minutes. Several electret ion chambers are usable with several pipes at a time and analyzed at a time using one measuring/analyzing equipment. 
The unit is adaptable for measuring contaminated tools, and other irregularly shaped objects. 

Validation and Calibration:
It is easy to validate and calibrate using standard alpha sources. 
Cost
Cost of Equipment: $ 4000 to $ 6000
Consumable cost of detector per measurement: Under $ 1

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