dweste... I'll offer a short vocabulary list

alpha particles... two protons and two neutrons... big but not very penetrating unless it gets inside of your body

beta particles (high energy electrons.. more pentetrating but small)..cesium 137,iodine 131, and strontium 90 are beta emitters and are chemically absorbed by the human body

gamma radiation...high energy electromagnetic wave with more energy than an x-ray

ionizing radiation... what happens to the electrical makeup of the chemistry of the body when a charged particle (beta (-) alpha (++))disrupts the normal electrical bonding.. damage about 10 to the 3rd power compared to size of the particle

half life...time it takes for 1/2 the mass of a radioisotope to decay... short means more particles are being emitted... more dangerous

decay daughters... as the alpha leave, the atom loses two protons and two neutrons, the atomic number is decreased by two, mass by four...as the beta leaves, basically a neutron is converted to a proton, and the atomic number increases by one, with no mass change (electron has virtually no mass)... the resulting daughters have a different proton to neutron ratio (when the nucleus has 1.5 neutrons to protons it is radioactive)and the change in nuclear binding energy (strong force) makes it an entirely new element with new characteristics.. in the case of uranium 238, the daughters Polonium 210, and Radon 222 are much more dangerous(short half life alpha emitters) if taken internally than is mother Uranium...this natural change (transmutation) continues until the neutron to proton ratio becomes less than 1 1/2 to 1... typically Lead 206 for U238.. the decay chain for fissionable Plutonium 239 and Uranium 235 will be different...it happens one atom at a time within the original large sample mass

rem (Roentgen equivalent man)...older term that describes the amount and radiation source type to describe danger to humans

rad.(radiation absorbed dose) amount of energy imparted to the body... typically x and gamma... most detectors will be in rads

Sievert... newer term for absorbed dose rem... 1 Sv = 100 rem

Gray.. newer term for rad ... 1 Gy = 100 rad

most pocket detectors will measure rads... alpha can be stopped by piece of paper (externally) and a beta by aluminum, so only the beta and gamma will penetrate to work the detector