[Ground-station] Radiation Susceptibility

[Tom Clark]

On 6/1/2018 2:19 PM, Bruce Perens via Ground-Station wrote:
> Bdale,
>
> Do you happen to know where there's a copy of Karl's old proposal?
>
> Finding a viable part is important. There are consumer or industrial 
> parts that we may choose to trust based upon someone else's testing 
> and our understanding of their architecture. The most common seems to 
> be a Microsemi (formerly Actel) part that is reported upon here:
> https://www.hevs.ch/media/document/1/20130612_cof_igloo-for-cubesat_1.pdf
> This goes to 40 krad.
> Parts that are specified as rad-hard seem to start in the $2000s and 
> go up from there. Do you know of less expensive ones?
>
I learned from Jan King (W3GEY) way back in the Microsat (i.e. AO-16) 
era some 30 years ago that 74AC logic was intrinsically good for ~200+ 
kRad total dosage and 74HC parts were good to around 100 kRad. The 
manufacturing processes also rendered plastic 74AC/HC parts to have good 
intrinsic vibration & thermal reliability.

Anything that used a charge pump in it went bad at 20-25 kRad, including 
DRAM and the clock circuitry in a number of small microprocessors.

We (AMSAT) also did a lot of testing on radiation susceptibility using 
medical x-ray machines cranked up to levels associated with "the patient 
is already dead so lets make certain that the remains are sterile";  
this including using x-ray machines associated with large animal 
veterinarians. As I recall some of the testing was done by Stacey  
Mills, W4SM and some by Paul ???, VE6???.

Jan King was a font of information on a lot of Co60 testing done by 
industry (especially @ Orbital Sciences). That's how we learned about 
the "magic" of 74AC logic.

73 de Tom, K3IO



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