jmdelahanty
commented
1 year ago Something that should be documented here is that a common consequence of this is that the phase offset algorithm prairie view implements gets frequently confused by the sudden drop in intensity and, for some reason (I'll post a video soon...) there's a very strange introduction of what looks like PMT preamplifier noise. This almost certainly causes issues in the offset algorithm too. What ends up happening is the phase offset, which when working correctly is either at 0 or a low value fluctuating around 0 - 200 maybe, can shoot up to something like 2k-3k and the images are inherently corrupted. This is due to the phase offset online correction being actively used when writing files to disk. So if the offset gets confused and causes a problem, the resulting images are completely useless later on in the recording. The band-aid has been to simply remove the offset correction entirely which doesn't always appear to be necessary for good image quality in general. In other words, the automatic value it determines during imaging is often 0 on its own and requires no intervention.
There have been emails back and forth between Bruker and I about these things that I'll document here eventually. I may have documented them already but don't remember...
Austin noticed while imaging on Monday that there's a shutter click very briefly heard at the start of LED trials. When Eun/Kush were editing something during their recent maintenance visit/team viewer they must have somehow changed the behavior of the Voltage Output experiment. I've spent a little time in Prairie View looking for why it's happening and I haven't found the source quite yet. I'll be sending an email to them tomorrow to ask about what's up/how to stop it.