Click here to make tpub.com your Home Page

Page Title: Implications of Power and X-Ray Production
Back | Up | Next

Click here for thousands of PDF manuals

Google


Web
www.tpub.com

Home

   
Information Categories
.... Administration
Advancement
Aerographer
Automotive
Aviation
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Logistics
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion
   
   

 



DOE-HDBK-1109-97
Radiological Safety Training for Radiation-Producing (X-Ray) Devices
Student's Guide
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 target, but a portion is radiated away as X-rays. As stated previously, the
electrical power of an electrical circuit is given by:
P=VxI
P is the power in watts or joules/second, V is the potential difference in volts, and I is the
current in amps.
The power developed in the anode of an X-ray tube can be calculated using this
relationship. Consider a 150 kilovolt (kVp) machine, with a current of 50 milliamps
(mA).
P = [150,000 (V)] [0.050 (I)] = 7500 W.
This is about the same heat load as would be found in the heating element of an electric
stove. This power is delivered over a very short period of time, typically less than 1
second. More powerful X-ray machines use higher voltages and currents and may develop
power as high as 50,000 W or more. Cooling the anode is a problem that must be
addressed in the design of X-ray machines. Tungsten is used because of its high melting
temperature, and copper is used because of its excellent thermal conductivity. These
elements may be used together, with a tungsten anode being embedded in a large piece of
copper.
14


Privacy Statement - Press Release - Copyright Information. - Contact Us

Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business