Better light through X-rays

July 7, 2005
An X-ray technique developed by physicists at the National Institute of Standards and Technology (NIST) sheds more light on temperature distribution in high-intensity gas-discharge (HID) lamps.

Scientists transform X-ray intensity data (left, a montage of five separate images) into an image of the spatial distribution of mercury atoms in a high-intensity discharge lamp (right). Blue indicates the lowest density of atoms, red the highest.


In the NIST technique, an HID lamp sits in an intense beam of X-rays. The X-rays penetrate the lamp's ceramic housing but are partially absorbed by mercury gas in the lamp, casting a shadow in the beam. A special digital camera behind the lamp captures a high-resolution, 2D image of this X-ray shadow showing the density of mercury atoms in the discharge. From the mercury distribution, researchers can determine the temperature distribution in the lamp. The technique has been used to quantify processes that consume power without producing light. Research indicates this method could be practical in industrial laboratories using small-scale X-ray sources.

HID lamps produce 26% of the nation's light output but consume only 17% of the electricity used for lighting. Better efficiency could save lots of money: HID lamps consume roughly 4% of U.S. electricity, equal to about $10 billion annually.

The highly efficient lamps have two electrodes in a ceramic tube that contains small amounts of mercury and metal-halide salts. An electric current between the electrodes heats the lamp, vaporizing the mercury and metal-halide salts, and producing a gas of electrically charged particles, or plasma. Metal atoms, excited by collisions with electrons in the plasma, emit light at many different wavelengths, producing a bright white light.

Sponsored Recommendations

The entire spectrum of drive technology

June 5, 2024
Read exciting stories about all aspects of maxon drive technology in our magazine.

MONITORING RELAYS — TYPES AND APPLICATIONS

May 15, 2024
Production equipment is expensive and needs to be protected against input abnormalities such as voltage, current, frequency, and phase to stay online and in operation for the ...

Solenoid Valve Mechanics: Understanding Force Balance Equations

May 13, 2024
When evaluating a solenoid valve for a particular application, it is important to ensure that the valve can both remain in state and transition between its de-energized and fully...

Solenoid Valve Basics: What They Are, What They Do, and How They Work

May 13, 2024
A solenoid valve is an electromechanical device used to control the flow of a liquid or gas. It is comprised of two features: a solenoid and a valve. The solenoid is an electric...

Voice your opinion!

To join the conversation, and become an exclusive member of Machine Design, create an account today!