In order to be able to perform unescorted access to areas where ionizing radiations are present, and to work with and use radioactive materials, workers at Fermilab have to pass a specific training which enables them to recognize the dangers and work safely, minimizing the radiation dose they get by performing their activities, and reducing the spread of contamination to the environment.

The training is not very hard -it involves the study of a 50-page document and the attendance of a 1-hour briefing, followed by a 40-question test. Every user or employee who may need to make a controlled access to beam enclosures or other experimental facilities where radioactive materials are stored or where materials have been activated by the particle beam, is required to take the training every two years. My last time was almost three years ago, and since I am starting a Scientific Coordinator shift at the CDF control room this week, I needed to renew my Rad Worker Training. I did it yesterday.

The funny thing is that I totally forgot about the 50-page document. Among the many things I had to take care of in order to travel to the US this week (putting students in the condition of working alone for a couple of weeks, organizing the trip, etcetera), the study of the document was pushed into oblivion. I suddenly realized there was something not right as I sat down in the training room yesterday morning, just before the 1-hour lesson. Hmmm, is there going to be an exam at the end ? I soon remembered about the multiple-choice test, and silently kicked myself while I tried to do my best and absorb the lesson as well as possible.

At the end of the lesson, I was unsure what to do. If I failed the test, I would then be unable to perform my shift duties for CDF, putting the experiment in the awkward situation of having to find a replacement for a full week -quite a hard task. I decided to ask the instructor for advice, coming clean about my failure to study the documentation.

His answer surprised me: "Take the test anyway, you have taken it before and you will remember most of the answers". He was right: it turned out that I was able to pass the test anyway. Some of the 40 questions were quite simple to answer; and although others were specifically meant to probe the understanding of the documentation, I got most of them right, despite the fact that my memory is quite bad. Or so I thought: I was not trusting much the study I had done three years ago, but  In the end, I got just four answers wrong.

One of those I got wrong slightly upset me. The question was: "What is the annual dose we receive from background radiation sources ?", and possible answers were 50, 200, 360, and 1000 milliRem. I was quite sure that the correct answer was 200 -I even periodically measure background radiation myself with a pocket dosimeter, and I know that in Venice, for instance, it is about 180 mR- so I was rather disappointed to learn that the correct answer (according to Fermilab) is 360 mR.

Instead, I was surprised to find out that I remembered in what cases radioactive waste is to be stored in 55-gallon yellow drums rather than elsewhere, whether the legal dose limit is 5000 mR or some other plausible number, that a "radiation area" is defined as one where the rate is between 5 and 100 mR/hour, what to do if I break a dosimeter while I am working, etcetera. I was proud to realize that my memory is not so bad after all, when I really need to rely on it. So, this evening I will start my SciCo shifts in the CDF control room with a clear conscience!