Hi, The damage you are thinking of is caused by ESD (electrostatic discharge) not EMF (electromotoric force). Although, supposedly, if the EM field from the X-ray gun was strong enough it could induce enough voltage within the chip through EMF that it could cause an ESD-like event. However, I find that highly unlikely as I highly doubt the coupling between the field and the chip is good enough to cause such an event. Furthermore, the issue with ESD events is that a significant amount of energy gets delivered in an incredibly short amount of time (we're talking nanoseconds here!). In case of the EMF, I would think there would be enough leakage currents to prevent any damage to the chip.
As far as I'm aware, the CF cards have EEPROM in them. EEPROMS work by storing charge under the gate in a MOSFET. The trick here is that the added charge will alter the threshold voltage of the device, thereby essentially turning it permanently on. Typically a dual-gate MOSFET is used for this and during the programming phase, gate charge is "injected" into a floating gate through tunneling. The "melting of puddles" you're referring to sounds more like polysilicon fuses (PROM) or metal laser link fuses (preprogrammed before packaging -- ROM). Both highly useful technologies, but not electronicly erasable. Tom On 3/5/06, Schlake <[EMAIL PROTECTED]> wrote: > Hard disks come up a lot in computer forensics. The amount of power > you need to blast at a hard drive to erase the data would be enough to > either melt or physically deform it. It is the delicate things like > CF cards, which work by melting tiny little pudles of metal, or the > camera sensor, which is (by definition) sensitive, that I would worry > about. And they supposed go through just fine. > > On 3/5/06, W S <[EMAIL PROTECTED]> wrote: > > Flash cards are pretty hardy devices. I'm not sure if the high powered > > X-rays are strong enough to induce EMF damage inside the chips? > > I would think the magnetic domains in a laptop disk drive would be more > > sensitive than flash memory. > * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
