F_N,
I don't believe that a 'normal' dosimeter will do the trick because it's designed to read the wrong sort of exposure.
We assumed this when conducting a trial a long time ago in HKG. The control badges that were left in the desk of the association headquarters registered more radiation than those carried by many of our crews for several months!
The reason we assumed when checking later was that since HKG is built on granite, which has a much higher normal rediation level than 'terra firma', the control badges were being 'contaminated' with this radiation.
Memory is a bit hazy as to which radiation is which but you definitely have to get the right kit to measure it.