From The mini-Annals of Improbable Research:

Investigator David Smith writes to notify us of a startlingly powerful new technology:

The March 16th issue of "Aviation Week and Space Technology" (p.13) reports that passengers at San Francisco International Airport will be asked to submit carry-on luggage for examination by a machine called the "Carry-on Luggage Profiler." Av Week reports that this remarkable device makes use of "3-megawatt average power" top- and side-mounted lasers to derive precise bag height and width data. The article goes on to say that initial trials at Des Moines International Airport have 'significantly increased the amount of luggage that was checked.'

The editors of mini-AIR asked how much power it takes to vaporize a piece of luggage.

Investigator Dave Thomson:

You may want to check out an article I published in Applied Optics some years ago, Vol 32, No 33, Page 6818, 20 Nov 1993. In any case, I'll attempt a quick first approximation to your question. I'll make the following gross approximations: A typical 10 micron diameter particle may require a fluence of 100 J/cm to completely vaporize. This implies an energy deposition of about 8 x 10^-5 Joules. Assuming a density of 1.7 (which may be low for luggage), the particle would have a mass of about 5 x 10^-10 g. Putting this together shows that one would need about 1.5 x 10^5 J/g, or 150 MJ/Kg to vaporize a macroscopic object. Even with a 3 MW laser (impressive as that is), a small piece of luggage of several Kg would require several minutes to be vaporized.

The mini-Annals of Improbable Research ("mini-AIR")
Issue Number 1998-04
April, 1998
Issue Number 1998-05
May, 1998
ISSN 1076-500X
Key words: improbable research, science humor, Ig Nobel, AIR, the

1998-04-20      Please Forward/Post This Issue! (*)

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