Hello All! Been a while since I last bloged. Unfortunately I haven't run across any interesting hits on my PM1703M. No radioactive people, no radioactive urinals. Pretty dull for the most part. I have had minor hits, for example, it seems that just prior to snowstorms, background radiation rates will rise, triggering alarms. Brick or porcelain objects will trigger alarms too, because of NORM (Naturally Occurring Radioactive Materials) found in those items. I think I really need to go to a hospital on a field trip. Might find many hits there.
Tonight I watched "NCIS" and as usual it was an enjoyable episode. However, like most TV shows it was filled with many "inaccuracies." To begin with a car (a late model Mustang) was destroyed in a fiery explosion. While Special agents McGhee and an Dins where investigating the destroyed car, they noticed that their cell phones would drop the signal while right next to the car's wreckage. McGhee rushes to his car and grabs an early sixties era CDV-700 (a yellow geiger counter with a hot dog probe). And notices that the wreck is radioactive. His first clue was the cell phone dropping it's signal. That is not true, gamma rays, beta or alpha particles, although the latter two are "charged", will not cause radio interference with earthly energy levels.
Special Agent McGhee's CDV-700 also clicked ominously while near the wreckage. Another TV fallacy. The CDV-700 he was using was not equipped with the CDV-705 speaker kit, nor headphones, so it will not "click." George Dowell (GeoElectronics) does remanufacture a wonderful unit called the LENi, which has an internal speaker, and typically is equipped with an internal pancake probe, or could be fitted with a hot dog probe, but the unit did not appear to be one of his CDV-700's. Also worth noting Ludlum makes a modern electronic circuit for the CDV-700 that clicks, but from all appearances the unit was a stock early 1960's CDV-700. I would expect a Special Agent of NCIS to have a much more modern unit, such as a Ludlum, Victoreen, TSA or Bicron.
The contamination was said to be caused by Cobalt 60, it also would have been much higher in close proximity to the wreck, but since most Cobalt 60 is in bar or rod stock, it would have been unlikely that the wreck would have shown any contamination, unless the Cobalt 60 it was ground to a powder. Worth noting, Cobalt 60 is a metal, and is highly radioactive, being a gamma emitter it is easily detected by a geiger counter. Grinding it to powder form would be very difficult at best.
Surprisingly, there was a moment of truth in the episode. The director of NCIS stated that the primary danger of a dirty bomb is the explosion, and that the intention of a dirty bomb is to scare and disrupt the populace of a city. People are scared of anything that has been deemed "radioactive." I am not saying that spreading radioactive dust over a city would be a good thing, it just would not be as deadly as TV and Hollywood would have you believe. A Dirty bomb would be an economic catastrophe, because of the huge expense in cleaning up what people perceive to be a life threatening hazard.
Another bad scene was when Special agents Davide and Dinozo found the lab where the bombs where built. They did not scan the area with the trusty CDV-700. I would suspect that that particular area at best would show light contamination, also I would think they would have been briefed on radiological hygiene prior to searching for a Dirty Bomb factory.
The source of the Cobalt 60 was also very questionable. Dental x-ray machines. I am unaware of any dental xray machine that uses Cobalt 60 to take a radiograph! In fact the dentist in the episode said that "these are not just tube xray machines, they used Cobalt 60." With today's emphasis on ALARA (As Low As ReasonAble) exposure rates, tube dental xray machines are a must! As a matter of fact when I took my wife to the dentist recently, the xray exposure was so fast and directly beamed my PM1703M did not pick up anything! An electrical circuit can turn on and off an X-ray tube much faster than a mechanical shutter could open and close to make a gamma ray radiograph with Cobalt 60. Industrial radiography equipment or Medical radiotherapy equipment may have been a much better choice.
The final scene involved Special Agents McGhee and Gibbs trying to find a dirty bomb in a hotel lobby. The radiation "sensors" (I prefer radiation detectors) they used appeared to be a Berkeley Nucleonics Model 951 nukeALERT (see http://www.berkeleynucleonics.com/products/model-951.html ). A very sensitive scintillation detector, easy to read. However, these units either beep or chirp, or have a vibration alarm. They do not squeal like a metal detector. They are very sensitive, and yes, I would love to have one. Anecdotally, I hear they are slightly more sensitive than a PM1703M, but I have yet to try one. However, I have read that the "sensors" may also have been SE Internationals Sentry, which does not squeal, they beep...
Although I enjoyed the episode, it was due to the basic storyline and the interaction of the characters. Hollywood and TV writers need to consult with experts in the fields that they may be writing about.