The affect of Alpha particles on memory

[sharkeeper]

Anyone have any idea how much alpha radiation (rems/hour) would be needed to cause a substantial problem with most memory modules. (ie flipped bits)

Cheers!

 

[CTho9305]

nearly infinite... alpha particles can be stopped by a sheet of newspaper IIRC, and definitely skin.
I think you're interested in gamma radiation, which only takes one to flip a bit. I imagine the amount required would be related to the percentage of area on the chip that is actually vulnerable to flipped bits.

 

[Shalmanese]

It is not Alpha radiation from outside the chip that causes flipped bits, it is due to trace amounts of radioactive isotopes WITHIN the RAM since manufacturing.

 

[CTho9305]

Originally posted by: Shalmanese
It is not Alpha radiation from outside the chip that causes flipped bits, it is due to trace amounts of radioactive isotopes WITHIN the RAM since manufacturing.

you learn something every day! I didn't know that. how much alpha radiation is normal? and *can* a helium ion flip a bit?
edit: considreing an alpha particle only wants 2 electrons, and i assume we dont store bits as that small of a charge yet

 

[sharkeeper]

It is not Alpha radiation from outside the chip that causes flipped bits, it is due to trace amounts of radioactive isotopes WITHIN the RAM since manufacturing.

You know you are exactly correct! Way back in the 70's traces of Radium which is both an alpha and gamma emitter were found responsible for this.

I guess my original question remains, however with gamma radiation instead of alpha. It seems like the gamma count is still fairly high here. My dosimeter shows 174 Roentgens since it was last recharged. :Q

Cheers!

 

[Antoneo]

I have also read that cosmic rays also can create a soft error in memory modules but the chances are quite low.