October 9, 2020 Meeting Minutes
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Post-meeting notes
- Dan presented an analysis and summary of the Lifesize runs
- Need to vet the laser profile data taken during the run - Josh will confirm the laser sizes (area) are correct based on the BeamGage measurements
- Need to add the first two BPMs to the list of PV's?
- VINJDIG__ pumps use Digitel power supplies. VIP____ pumps are more sensitive at lower vacuum and use a different power supply.
- Cristhian presented ionization-desorption multiplication - primary electrons create ions. These ions hit the photocathode and produce secondary electrons due to secondary electron yield (SEY). These electrons, due to their large momentum spread, are likely to hit the beampipe and/or gun chamber walls and desorb gas, which gets ionized and repeats the process indefinitely.
- SEY can be greater than one in some circumstances, though the ionization probability for a single electron is extremely low, so although this process is possible, it does not seem stable.
- Need to figure out the source of the radiation signals picked up by the rad monitors. Since we determined that radiation is unlikely (if not impossible) to penetrate the beam pipe and gun chamber walls, it must come from another source, perhaps far away from the monitors?