I work in Nuclear Medicine.
A few weeks ago, I received a telephone call from an 84-year old patient of mine that I did a bone scan on a couple of days earlier. He told me that he was on line at a 7-11 buying a lottery ticket when a police officer came into the building with a radiation detector, walked right over to him and started interrogating him to find out why he was setting off his Geiger-Muller meter.
Even after 20-plus years in the industry, his phone call stunned me. The fact that they had detectors that could sense a very tiny amount of (almost-decayed) radiation circulating the blood stream of a man almost two days after his procedure was amazing to me, as even the detectors that I use in my office stop beeping the minute a patient moves just a few feet away from them.
This incident convinced me that there’s just no way that anyone can get any weapons-grade isotopes into this country, as our satellites and other detectors that we have will probably spot them the minute they depart for one of our coasts.
At least I hope so.
Why not post a “do it yourself” blue print?
Hate to disappoint you, but recent tests, using DHS-approved detection equipment, failed to identify some containers that were used in controlled tests. The problem with identifying containers is two-fold. First, the container can use large amounts of shielding material, as in the DHS test. Second, so many containers enter our ports that DHS cannot hope to test all of them. A locked/sealed container could be delivered anywhere in the country before it gets a command or GPS-triggered signal to explode.
Good quality materials aren’t in the same league of emissions as medical isotopes with shorter half-life. I am assuming use of gamma emitter 99mTc as the most common.
If you had Naval quality pu 239, then neutron emissions would be minimal, and the alphas easily shielded. If a non- government had to process their own materials, likely it would be contaminated by 240 and 238 and radiating strongly. A search using a neutron pulse generator would be seeking a like echo.
Encasing a weapon in a neutron absorber would reduce its signature. Placing it concealed along the keel of a ship would also reduce odds of detection.