We have completed the testing of 6 chips at around 4:45 AM (CDT, Local time) which were scheduled to be completed by May 31st 8 AM thanks to the newly designed two test boards which have three chips per each. It reduced the beam time by a factor of three. So instead of 32 hours, we could finish in about 10 hours.
Here is a test summary.
1. ADC chip: Start to show SEL (Single Event Latch-up) at around 10.4 MeV cm2/mg with Argon particles of 15 MeV/nucl. This corresponding to about 10-3/cm2/day and with 1000 days of flight, we will see one SEL per chip during the duration. And for the 80 ADC chips in the CAL, it means about one SEL per 12 days. So this chip can be used in the CREAM.
2. DAC chip: No SEL up to 49.3 MeV cm2/mg with Xenon particles. 10-5 SEL for 1000 days per chip.
3. 74HC123 (Monostable vibrator): No SEL up to 49.3 MeV cm2/mg. 10-5 SEL for 1000 days per chip.
4. MUX chip: The same as the above two. Shows current increase at LET of 85.4 MeV cm2/mg with Gold particles but still working.
5. Comparator chip: Single event upset from LET of 22.8 MeV cm2/mg but no SEL.
6. Current monitor chip: No SEL/SEU up to 49.3 MeV cm2/mg.
In conclusion, all 6 chips are tested and found to be OK in 1000 days of flight in the ISS.
Best, MooHyun
