Dear Reza Taherzadeh Mousavian ,

Some ideas:

There may be an error on the detector side.

a) Either there may be no voltage applied to the detector, or

b) the detector voltage is too high...

c) low level discriminator (LLD) set too low?

With respect to the acquisition parameters you gave above:

lower voltage and current significantly and see what's happening.

Maybe sparking is happening somewhere...(is the sample sufficiently grounded?)

Good luck and

best regards

G.M.

Thanks Gerhard. I think current might be too high and I'll check it. Do you know what is OL Aperature?

Dear Reza Taherzadeh Mousavian ,

to my opinion, OL stands for objective lense.

The problem was easily solved. The camera was ON! :)

@GERHARD MARTENS

Thanks Reza Taherzadeh Mousavian ,

for feed back.

Fortunately some problems/challenges will solve themselves...

Dear Reza Taherzadeh Mousavian ,

I have the same problem on Axia Thermo Fisher. What means "The camera was ON"?

Aleksey Yakushkin Thanks for your message. When your camera for observation of the sample holder inside the chamber is ON then you won't get true EDS results. You should turn it off to have dead time around 45-75 percent.