[time-nuts] 88Sr+ ion-clock live stream

[paul swed]

Hello to the group. This is great to watch and see the development of an
exotic clock. I guess I need a bit of help in understanding what I am
seeing. To a point I understand Zeeman images in respect to a cesium
reference at least. But in that case there is a single higher peak thats
the correct one to lock to. In the image thats shared is this a case of
saying the multiple energy level can be seen but no attempt is being made
to choose one peak to work with?

Like the speed up version a bit to impatient.
Thank you for sharing with time-nuts Anders
Paul
WB8TSL

On Sat, Dec 7, 2019 at 7:39 AM Anders Wallin <anders.e.e.wallin at gmail.com>
wrote:

> Hi Jim, yes you are right  the background is a camera-image (about 30x
> magnification, maybe 1um per pixel). We use a microscope-objective, a
> narrow 422nm bandpass filter, then an image-intensifier, and a fairly
> standard CCD camera that looks at the output of the intensifier. When
> everything is working and optimized I think a good quality (high QE) CMOS
> or CCD camera alone could work. I think it would be interesting to try e.g.
> a budget camera made for astrophotography at some point.
> If you have lots of money then an EMCCD camera (30-50k maybe) is a good
> solution.
>
> The camera is only used for observation and coarse diagnosis of major
> problems. For quantitative measurements we have a beam-splitter that
> directs most of the fluorescence towards a pinhole followed by a PMT
> photon-counter. The ARTIQ controller can time-stamp each incoming photon
> with 1ns resolution (but this creates a lot of data) - mostly we just bin
> the counts into some gate time and look at the time-series of counts per
> 20ms or so.
>
> The live stream is created with OBS. It captures the camera image as
> background and can overlay any images/websites etc. that we can imagine.
> I create the Zeeman-spectrum barchart in matplotlib as a PNG image with
> transparent background - once per minute, from data we store in InfluxDB.
> The X-axis labeling was not so good - need to improve that next time.
> Somehow indicate that line-center is 445THz and the peaks really are <1e-12
> wide (narrow!).
>
> For the impatient, I made a speedup (128x) version of the live-stream:
> https://www.youtube.com/watch?v=f3edhdwqXgc
>
>
> Anders
>
> On Sat, Dec 7, 2019 at 1:48 AM jimlux <jimlux at earthlink.net> wrote:
>
> >
> > > The central bright dot is fluorescence at 422nm from laser cooling a
> > single
> > > trapped 88Sr+ ion. The ion emits about 1e7 photons/s at most and we
> > > currently detect about 500 of those in a 20ms detection window (using a
> > > Hamamatsu PMT module).
> >
> > Very cool. A question about the display - it's a video image of the
> > fluorescence, and the graph is superimposed on top of it?
> >
> >
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