Last week we were pulling the nightshift in Cave 4B at Lawrence Berkeley National Laboratory, using the 88-Inch Cyclotron facility to perform Heavy Ion Testing on the VA10820 Arm Cortex-M0 based microcontroller.
The cyclotron generated Boron, Neon, Argon, Kryton and Xenon charged particles that were used to directly irradiate the MCU while it was operating in various modes. The same tests were conducted using the VA10800 ‘extreme temperature’ MCU that is identical to the VA10820 ‘rad hard’ MCU except that the VA10800 does not include EDAC, Scrub engine, Dual Interlocked Cells and Triple Modular redundancy. The VA10800 acted as a control group to test the effectiveness of the radiation effects mitigation features of the VA10820.
Testing is a two-to- three person job, controlling the DUT (Device Under Test), controlling the beam fluence and logging the results. These results are used to create a Weibull distribution that can be used to characterize radiation performance of the microcontroller.
The VA10820 stood up bravely to the challenge, withstanding a strong fluence of Krypton that Superman himself would have struggled with. Lesser mortals (and microcontrollers) than Superman would of course have a bigger problem with Xenon than Krypton, as Xenon has a larger atomic mass (131.293u versus 83.798u), but the VA10820 continued to operate happily while being bombarded directly by Xenon.
Checkout the thickness of the concrete door on Cave 4B and the set-up inside the cave with the heavy ion source connected to a vacuum chamber where the irradiation of the DUT occurs. Incidentally, there is an escape hatch at the back where Superman can crawl out when the Krypton source is switched on.