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Thanks for bringing that up Paul. I was thinking along the same lines
so my plan was to go with a transmitted specimen, but that might not
be possible if the TL bulb is not stable at very low brightness; I
might have to get creative with the illumination. I don't even know
if 30s is long enough exposure for dark current to dominate. Maybe I
can use a bead slide and turn the fluorescence excitation way down (at
the lamp and with the aperture diaphragm)? Suggestions for dim, nil
background specimens are welcome!
If cameras reach lowest temp. within a few minutes then practically
speaking this is all moot, I'll just turn the cameras on 10 min.
before imaging. But I'm still curious how much of an effect cooling
has, and how long the exposure needs to be before cooling offers an
advantage. I hear that thermal cycling is a problem (and in fact I
have one camera where the cooling system died) so if cooling gets me
nothing I'll just keep it off and turn it on only when needed. I
guess I can calculate that from the noise specs, and I would if dark
current w/o cooling were reported, but I'd still want to see for
myself with data.
-Esteban
On Sat, May 12, 2012 at 6:02 PM, Paul Herzmark <[log in to unmask]> wrote:
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Esteban,
>
> I am curious what kind of sample you expose for 30-60 seconds? Won't
> background fluorescence kill you?
>
> Paul Herzmark
> Department of Molecular and Cell Biology
> University of California, Berkeley
>
>
> On Sat, May 12, 2012 at 2:28 PM, G. Esteban Fernandez <
> [log in to unmask]> wrote:
>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
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>> *****
>>
>> Hi all,
>>
>> 1) I'm curious how much time, roughly, it takes for a Peltier-cooled
>> CCD camera to reach the lowest temperature. Are we talking a few
>> minutes or closer to an hour or more? I have several brands of cooled
>> CCDs of different vintages and I'm just looking for a "rule of thumb",
>> if possible.
>>
>> 2) I do plan to test my cameras myself: I was thinking of imaging a
>> timelapse of a dim & stable specimen (requiring something like 30-60
>> sec. exposure) after turning cooling on to see at what time noise
>> reaches a minimum. Any suggestions for other ways to test this are
>> welcome.
>>
>> Thanks,
>> Esteban
>>
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