Units - DOE-HDBK-1109-97_reaffirmed20070047

DOE-HDBK-1109-97

Radiological Safety Training for Radiation-Producing (X-Ray) Devices

Instructor's Guide

Lesson Plan

Instructor's Notes

Examples of non-ionizing radiation include radio

waves, microwaves, and visible light.

For radiation-protection purposes, ionization is

important because it affects chemical and biological

processes and allows the detection of radiation.

For most radiation-protection situations, ionizing

radiation takes the form of alpha, beta, and neutron

particles, and gamma and X-ray photons.

X-rays and gamma rays are a form of electromagnetic

radiation. X-rays differ from gamma rays in their point

of origin. Gamma rays originate from within the atomic

nucleus, whereas X-rays originate from the electrons

outside the nucleus and from free electrons decelerating

in the vicinity of atoms (i.e., bremsstrahlung). Module

102 discusses how X-rays are produced.

UNITS

Roentgen (R), a measure of radiation exposure, is

defined by ionization in air.

Rad, a measure of the energy absorbed per unit mass.

It is defined for any absorbing material.

Rem, a unit of dose equivalent, which is the energy

absorbed per unit mass times the applicable quality

factor and other modifying factors.