Quoting Steve Moulding <
fti1983@...>:
> Anyone on the list have experience / knowledge of using PIC microcontrollers
> which may be exposed to X-ray beams? A customer has an application for use
> in radiation therapy rooms, and the electronics package will occasionally be
> in the path of the therapy beam during patient exposure; due to the nature
> of the package, this is unavoidable. The question is: will this eventually
> cause the electronics - specifically the microcontrollers - to fail? Some
> empirical testing done Saturday in a Cancer Center showed that the
> microcontrollers will eventually fail, but only after extended exposure -
> approx. 1 1/2 hours in a continuous beam, something that will not happen
> with a patient. If the package is exposed intermittently, will the
> radiation effects be cumulative? Tried Microchip & Google with very little
> useful info uncovered. Thanks,
> Steve
I would expect any problems to be in program memory retention. Maybe you
should socket the chips and then if replacement or reprogramming turns out
to be required it won't be fatal.
Ionizing radiation will eventually cause threshold shifts and changes in
analog parameters, as well as increases in leakage current. You may find
contemporary information on this sort of thing hard to come by- rad-hard
technology is considered military (or dual-use) by some nations, and
suppling information that can be misused is subject to rather severe
penalties.
Best regards,
Spehro Pefhany
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