Radiation risks
Classified radiation workers (working in hospitals and nuclear plants) are permitted no more than 20 milliSv per working year (so 9mSv is fairly low).
To put this into context, if you live near Sellafield, the background radiation averages 2 mSv per year, whilst in Cornwall the background count is about 8 mSv per year.
Pregnant women have a much lower dose limit, but I can't remember it.
Dose meters may be obtained through National Radiation Protection Board (UK). I think you have to have some training though-might be worth checking.
The relevant regulations are Ionising Radiation Regulations (1999).
Didn't Concorde used to have a radiation monitor?