Answer to Question #1975 Submitted to "Ask the Experts"

Q

I am working in the field of terrawatt laser-plasma interaction to produce high-energy charged particles such as electrons or protons. Also, gamma rays and x rays are produced by the same technique. The experiments are carried out without any shielding or protective measures. What should be done to protect myself from the exposure to such radiation? And what safety standard should I follow in this case?

A

The new phenomemnon of laser plasma wake-field acceleration of charged particles has been made possible by the invention of techniques for terawatt laser pulses of femtosecond duration. (See, for example, Extreme Light by Gérard A. Mourou and Donald Umstadter; Focusing light with the power of 1,000 Hoover Dams onto a point the size of a cell nucleus accelerates electrons to the speed of light in a femtosecond, Scientific American, May 2002.) A few major institutions are exploring this new technology. At our institution we have performed extensive radiation surveys and instituted radiological controls to protect workers from the ionizing radiations produced by these new high-power laser experiments. I suggest that you contact the radiation safety organization at your institution for assistance in identifying the radiation hazards and implementing engineering and administrative controls most appropriate for the experiments you are carrying out. Gary Zeman, ScD, CHP