This paper is intended to explain the difference in the Effective Dose to humans between 2 different activities (7.5 uCi and 10 uCi) of 133Ba isotope used in a hand held contraband detector relative to ordinary risk we face in everyday life.

A competitor of ours has offered a version of their unit which is 7.5 microcurie of radiation against our 10 microcurie., claiming that this is safer for the user, In fact, the increased dose to a user of a 10 uCi source over a 7.5 uCi source for a worst case scenario is essentially equal to what one gets in one second of airplane flight on a cross country trip from Washington, D.C. to Los Angeles, CA, a total flying time of up to five hours  or 1 in 18,000

10 Microcurie Source

Now let’s compare both these radiation source activities and the actual working life of the source.  The working life is based on the sources initial activity and the half-life of the isotope.  For 133Ba, the half-life is 10.53 years.  So for a 7.5 uCi source, the working life is about 35-40% less than the working life of a 10 uCi source.  This translates that the dollar per dollar cost of the 7.5 uCi source is much higher than the cost of the 10 uCi source!       And finally another consideration is the scanning time for the contraband detector.  Excluding other factors involved, a 7.5 uCi source has 25% less photons/sec output than a 10 uCi source and this in turn increases the length of time it takes to complete a scan.    This also may reduce the probability of positively identifying a concealed item (contraband)

The Xpose has graphing & digital display, available tablet remote control of all functions, Bluetooth and  is MIL STD 810G -   Water Resistant to IPV56 ( waterproof available on request) -  ISO9001:2008 and most importantly sold under an Exempt Radiation License from the NRC.  In other words virtually no restrictions on sale, possession of transfer of the unit.

Our competitor has none of these features.

In short, when comparing the 2 activities (7.5 uCi and 10 uCi) 133Ba sources in hand held contraband detection systems:

  • No substantial increase of dose to the user, therefore no increased hazard
  • Dollar-to-Dollar cost for a 7.5 uCi is higher factoring in half- life of the source
  • Longer time to complete a scan with 7.5 uCi
  • Reduced probability of contraband detection with 7.5 uCi as compared to 10 uCi
  • Exempt Distribution License from NRC ONLY for Xpose

For those interested in the science and math behind these conclusions we do have a detailed white paper available upon request.