Cooling time for CCD cameras

[G. Esteban Fernandez]

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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

[Nico Stuurman]

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On May 12, 2012, at 2:28 PM, G. Esteban Fernandez wrote:

> 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.

Our EM CCDs (from Hamamatsu and Andor) cool to -70 C in a few minutes.  The build-in sensor's  temperature can be read-out through software.

Best,

Nico

[David Baddeley]

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Most modern cameras reach their temperature setpoint within about 5 mins (some are considerably faster). You can generally read the temperature out through software, and don't need to rely on measuring the noise. If you do measure noise, keep in mind that the baseline also tends to change with temperature.

Cheers,
David


------------------------------
On Sun, May 13, 2012 9:28 AM NZST G. Esteban Fernandez wrote:

>*****
>To join, leave or search the confocal microscopy listserv, go to:
>http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>*****
>
>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

[Paul Herzmark]

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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 <
[hidden email]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> 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
>

[George McNamara]

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Hi Esteban,

As others have noted, cooling is pretty quick. You do NOT want to do
this with a fluorescent specimen - you would be getting both
photobleaching and camera cooling.

Cooling affects the dark current, rule of thumb is dark current
decreases with every ~7 C of cooling. A simple test - I'll use MetaMorph
as an example:

1. Start everything, except the camera (MetaMorph will typically
complain about the camera, just say no to try again).
2. Configure the exposure time to 1 ms (Acquire image command).
3. Create a journal and taskbar button to do Acquire Timelapse, say one
exposure per second, 5 second interval, for (say) 15 minutes, to stack
-- or disk if you want more data. Make the Taskbar visible so you can
clikc on the journal button immediately after starting MetaMorph next time.
4. Setup the light path so NO LIGHT goes to the camera (or put the lens
cap on).
5. Exit MetaMorph.
6. Turn on the camera, immediately start MetaMorph, click the journal
button. When done, save the data. Simplest to use Apps - Graph
Intensity, but Measure Regions is fine.
7. Go have lunch.
8. Close the stack or change the file save name and/or path.
9. Acquire another timelapse after the camera has fully cooled.

On my ORCA-ER(s), starting intensity is around 300, takes a couple of
minutes to reach ~200 (12-bit range). On my ORCA-II ERG, takes longer to
cool to -60 C, offset when cool is ~600 out of 14-bit range.

//

Speaking of timelapse tests - the centenary of the discovery of cosmic
ray particles by Victor Hess is 7 August 2012
(http://en.wikipedia.org/wiki/Cosmic_ray and M. Friedlander 2012 Nature
483: 400-401 do not currently give the date - date from P. Carlson 2012
Physics Today Feb 2012: 30-36). I encourage everyone with a camera that
can be set to "no light" to do either a Friday August 3 (end of work) to
Monday August 4 (start of work) or overnight(s) August 7. No light, max
exposure time for your camera, continuous timelapse. Easiest way to
summarize the dataset is to aet up your software to do a maximum between
the newest image and an "accumulation" image (of course test this before
the big date). I recently submitted a 30,000 frame (ORCA-ER, 10 second
exposures) to one of the microscope company photo contests.

As for what to do with the data - I suggested to one of my colleagues
that they take the lead in posting this request to the listserv. I
haven't seen a post from them (yet). If they decide not to organize
everyone's image, perhaps Esteban will?  If not, I'll consider making a
montage of everyone's accumulation images for posting someplace on the
Internet.

George
p.s. I am not a fan of N=1 experiments, so I want to credit M.
Friedlander (Nature article) for pointing out that:

"In 1932, Carl Anderson was using a Wilson cloud chamber with a large
magnet to study cosmic rays when he observed a particle that had the
mass of an electron, but a positive charge. The discovery of the
positron, as Anderson named the particle, was recognized when Anderson
shared the 1936 Nobel prize with Hess."




On 5/12/2012 5:28 PM, G. Esteban Fernandez wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> 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
>
>    

[G. Esteban Fernandez]

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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 <[hidden email]> 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 <
> [hidden email]> wrote:
>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>> *****
>>
>> 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
>>

[Julio Vazquez]

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Hi Esteban,

not sure why you would need a specimen at all..... I typically check cameras by taking several dark exposures at different exposure times (such as from 10 ms to 1 second) and look at the image histograms. This can be very informative, and will allow you to not only measure or estimate dark current and thermal noise, but will also show dark and hot pixels, and sometimes other funky things. If the camera has different read out modes or gain settings, it is also useful to test those. Taking varing exposures of an actual (ideally homogenous and non-bleaching) sample can give you additionla info, such as how linear the response of the camera (and/or individual pixels) is. We typically do that with fluorescent plexiglas slides.

=
Julio Vazquez
Fred Hutchinson Cancer Research Center
Seattle, WA 98109-1024

http://www.fhcrc.org

==

On May 12, 2012, at 2:28 PM, G. Esteban Fernandez wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> 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

[Csúcs Gábor]

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Dear All,

I'd really appreciate if you could make potential candidates aware of the
position advertised below. It is not directly a confocal microscopy
related position (my excuse for that) but certainly very much linked to it.

Thanks    Gabor




Head of the Data Analysis Unit for Light Microscopy and High Throughput
Screening
 

The Light Microscopy and Screening Centre (LMSC) of the ETH Zurich is
one of the leading academic core facilities in Switzerland offering access
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Due to strongly increasing demand, the LMSC will set up a
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We are looking for a scientist with proven research
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immediately while building up the group to full-scale operation within the
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2 years, including recruiting further staff member(s) and fundraising for
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The suitable candidate is having a PhD degree in Computer
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Please send your CV + publication list, including a
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Further information is available on www.lmc.ethz.ch
<http://www.lmc.ethz.ch> or contact Dr. G. Csucs
([hidden email]).

[Xuejun Sun]

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Hi, Esteban,

I did this last year with one of my old CoolSnapHQs (~10 yrs now) which cool
down to -30C. I can share some of the data (just couple of graphs and a
movie show the cooling effects) with anyone who is interested by emailing me
privately.

Here is a brief summary of the finding:

The camera is cooled down quickly. Within ~3-5mins, there is no more visible
hot pixels. However, it takes ~20mins to stabilize (measuring average
intensity, standard deviation and signal-noise ratio of the images). I
tested another EMCCD which cools down to -70. It is faster but still needs
about 10mins to stabilize.

You just need to set up a timelapse imaging with all light to the camera
blocked. It sounds easy but it takes several attempts to get it right as you
need to start the camera from cold. Do as fast as you could because the
cooling rate is pretty rapid and you miss the interesting part (first 2-3
mins).

Best wishes,

Xuejun


-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]] On
Behalf Of G. Esteban Fernandez
Sent: Saturday, May 12, 2012 3:28 PM
To: [hidden email]
Subject: Cooling time for CCD cameras

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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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