Determining Electrical Power

DOE-HDBK-1109-97

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

Instructor's Guide

Lesson Plan

Instructor's Notes

iii. Determining Electrical Power.

Power, which is measured in watts (W), equals

voltage times current (P = V x I). For example, a

10 kVp device with a current of 1 mA uses 10 W of

power.

(Insert facility-specific examples for determining

electrical power.)

INTERACTION WITH MATTER

Scattering.

When X-rays pass through any material, some will

be transmitted, some will be absorbed, and some

will scatter. The proportions depend on the photon

energy, the type of material and its thickness.

X-rays can scatter off a target to the surrounding

area, off a wall and into an adjacent room, and over

and around shielding. A common mistake is to

install thick shielding walls around an X-ray source

but ignore the roof; X-rays can scatter off air

molecules over shielding walls to create a radiation

field known as skyshine. The emanation of X-rays

through and around penetrations in shielding walls

is called radiation streaming.

ii. Implications of Power and X-Ray Production.

When high-speed electrons strike the anode target,

most of their energy is converted to heat in the