Dear all,
we have a Nikon A1R laser scanning confocal microscope in our lab, and recently I’ve been seeing a strange “overexposed pixel” issue in the red channel only. Bright comet-like dots the size of one pixel appear all over the screen.
I have attached some example images. The issue occurs with different objectives and different samples (fixed / live cells). The “overexposed pixels” (probably not the right term) appear in a different location in each image / frame. Has anyone seen something similar, or has any idea what could cause this?
example images →
In the four_channels.png image you shared, I see a dotted pattern in the green channel. Is this expected? It is not clear to me if this is a detector issue or perhaps, laser / pixel clock related. Do you see this with both galvo and resonant scanners? And for galvo; does the pattern change when you use different dwell times?
To get to the source of the issue, a few things you could try:
Use chroma fluorescent slides → do you see the dots in only the red channel still?
Compare dark image collected by two detectors channels (lasers off & no objective) → dotted pattern still visible when boosting the LUTs? (check with low and high detector gain).
Check the metal clad MM fiber leading from the A1R scan head to the detector unit is not touching some vibrating components.
Has anything changed recently around the scope itself? Unlikely to be the source but interference of electronics nearby perhaps? I’ve worked with confocal systems where 3G/4G signals from mobile phones caused interference patterns.
Over all, best to contact Nikon service team and ask for a repair quotation.
Best,
Teo
