Trade.Information

Product Name: TRITIUM ON SURFACE

Product Description

System: Electret Ion Chamber 
Lab/Field: Field ( Surface contamination measurements)
Radiation detected : Low energy beta radiation from tritium, C-14, or from Tc-99 

Operation 

This system is a passive integrating detector for field measurement of surfaces contaminated by low energy beta emitters such as tritium, C-14 or Tc-99. It consists of a charged Teflon disk(electret), an 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. The chamber is deployed directly over the surfaces to be monitored for a desired time interval. The beta particles enter into the air volume of the chamber and ionize 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 in charge divided by the time of exposure) is proportional to the contamination level on the surfaces. 

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 dimensions of the chambers are optimized for specific isotope. 
Specificity/Sensitivity: 

Several hundreds of the detectors can be deployed and analyzed at a time using one measuring/analyzing instrument. These have sufficient sensitivity for measuring airborne tritium in occupational environment or during the progress of decontamination processes. For measuring other low energy beta emitters, the EICs have to be calibrated with reference sources. 
Applicability for Site Clean up 

This method is not specific to the isotopes being detected. For measuring low levels on surfaces a parallel detector with beta shield may have to be deployed to determine the correction for background radiation. Lower limit of detection depends upon the exposure time. A level of 6300 dpm/cm2 and 262 dpm/cm2 of tritium contamination can be detected in 1 hour and 24 hour respectively. A level of 454 dpm/cm2 and 18.9 dpm/cm2 of Tc-99 contamination can be detected in 1 hour and 24 hour respectively. By increasing the deployment times, still lower levels can be measured. 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

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