Answer to Question #883 Submitted to "Ask the Experts"

Q

Dear Sir: I am a jeweler and have read some correspondence recently regarding irradiated gemstones (topaz) from Asia and South America. An otherwise dull stone such as topaz can be brought to a deep cobalt blue through exposure to radiation. There are safe ways to do this, and there are quick ways to do it to maximize profits. I am looking for a radiation detector. I was thinking that in the event of an accident or a major fuss with China, it just might be handy to be able to tell what's "Hot" and what's not. I have seen the old yellow CD Geiger counters on the surplus market, but any electronics that is 40 years old and has not been calibrated since manufacture has an issue of reliability that I would like to avoid. My question is: What do you recommend? Cheap (less than $100 I hope), reliable, sensitive, yet able to read high radiation levels also, and alpha, beta, and gamma. I found your site on the Web while searching for radiation detectors; sorry for the intrusion if you are not a technical guy. Please forward this on to a man in the know. Best Regards, Lamar Johnson, Portland, OR

A

Let's see, "cheap (less than $100 I hope), reliable, sensitive, yet able to read high radiation levels also, and alpha, beta, and gamma." That's all? If "cheap" is the major criterion, your best option might be to purchase it online via auction. Numerous survey instruments are sold on Ebay. While most are old Civil Defense instruments, some are relatively modern. Needless to say, there are risks associated with such a purchase. Inevitably, you get what you pay for. My recommendation would be to purchase a new instrument, such as the Radalert (just do a search using that keyword and you will find numerous companies offering it for sale). The latter retails for approximately $300. It is simple to use and can respond to all three types of radiation you mentioned. It has the additional advantage of being small enough to fit into a pocket—something that should be especially useful for evaluating irradiated gemstones. There are sure to be many other instruments available that might also fit your needs. Try searching the online catalogs of the HPS affiliates. Since you expressed interest in being able to use this detector following "a major fuss with China," it would be a good idea to purchase a spare set of batteries. And be sure to read Nuclear War Survival Skills by Cresson Kearny—go to the Oregon Institute of Science and Medicine Web site. Paul Frame, CHP, PhD