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Ion Pump QPC Controller Issues, Improvements Incoming

Mitchell Cabral

We contacted Gamma Vacuum regarding issues with long-run ion pump QPC controllers and their noisy signals in August. This led to a meeting with Edwards Vacuum, their partner company, where we discussed a temporary solution to update the firmware with an unreleased version. This unreleased firmware was also being used to solve similar issues in Germany as well as the Accelerator Departmentin AD at SLAC. In October, we updated the firmware on B940:009:R03:PCI:01 inside of the FEE. This improved the stability of the pressure report on two of the three working ion pump channels, however there was still some variance in the third channel. 

A second ongoing issue that was not solved with the firmware update, is the inability to run all four QPC channels at once without error. Even so, another problem was discovered where When all four channels (and sometime even three , or two channels cannot be ) run stably, so we must replace the controllerthe device will eventually error-out all channels. These topics were discussed with Edwards as well, but the this fix is replacing the CPU for the former, and uncertain for the latterto replace the CPU chip in each QPC or to procure completely new QPCs with necessary hardware updates. All QPCs with the 4-channel error must be sent back to Edwards so that they can replace this chip then sent back, but this is not possible with supply-chain issues and critical dates for beam. We are pushing to get new QPCs that , which were ordered last year, to be prioritize in their backlog so that we can replace these controllers and send the defective ones out to be fixed.

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