First, try your Clip and make sure that it plays music OK.
An airport scanner can be any one of several types, X-ray, RF metal detector, or even low power microwave (millimeter-wave) for the new full-body scanners. The RF energy of these is worlds apart from the 1kW radar transmitter used to nuke your soup, and shouldn’t harm you, nor your little Sansa.
Did anything change on your computer?
Plug in your Clip and let us know what activity you see. It’s possible that there may be a hardware issue with the USB bus system on your Clip, and it may be coincidence that it failed following your trip.