[Cytometry] Consistent difference between CST vs Manual laser delays

Chuan En Lam chuanen.lam at gmail.com
Tue Feb 18 19:21:39 EST 2014

Hi all,
Recently we seem to be seeing consistent differences between CST set laser
delay values vs Manual laser delay values on our AriaIIu.

Instrument setup/details:
AriaIIu (Blue/Red/Violet laser) inside ClassI CAS hood.
Morning cold temp: 20.0deg,
Start up to CST: 22.0 deg
2hrs after start up to end of day: about 24.0 deg

Mostly, after initial fluidics startup, CST would be run. We then double
check with manual laser delay setting using single peak beads and 8 peak
rainbow beads.

We found a consistent requirement to shift the laser delays by about 0.5
compared to CST to get optimum position. This is in general consistent
across nozzles (70um, 100um). We are not sure if temp changes has an
effect, or was the flow cell dirty (have done flow cell cleans with
Decon/Coulter cleanz).

In one scenario, 70um nozzle, after flow cell clean.

_________CST AM____Manual AM____12PM____4PM____4pmCST____4pmManual
Red           -43.06            -43.50           -43.50      -43.50
-42.86            -43.36
Violet          40.64             40.18            39.92
39.92         40.46             39.86

Has others seen similar effects or ideas what this might indicate?

Normal condition sorting (log scales etc) seems to be ok with clean


Eric Lam
Flow Cytometry Lab Technician
Garvan Institute of Medical Research
Sydney, Australia
Ph 9295 8431
e.lam at garvan.org.au <r.salomon at garvan.org.au>

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