My original email was apparently cut off mid-sentence by some sort of
formatting problem.
The response to the price question was supposed to read:

I emailed the marketing manager and the response was:
"The same as the 5071A-C001 and 5071A-C002.
We don’t publish the list price, you have to quote, but in general
it is greater than $70k."

On Tue, June 13, 2023 12:28 pm, djl via time-nuts wrote:

The PTTI paper which originally kicked off this thread stated that the
design goal was production until 2035.  The thought was that a different
technology may have superseded the 5071 design by then (the design will be
nearly 45 years old at that point).

2. what's the price?  I'm assuming the answer to the

See above.  I see plenty of cars which cost well more than that around
here, but having a 5071 probably doesn't impress your neighbors as much.

--
Chris Caudle

Thanks, Chris. It's apparent that they are still handcrafted and fussed
with until working, hence the cost is high. Certainly after 45 yr, the
engineering cost should be well amortized...

On 2023-06-13 18:54, Chris Caudle via time-nuts wrote:

"It's always something."
Roseanne Rosannadanna
----------------------"
Dr. Don Latham  AJ7LL
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304

On 6/13/23 5:54 PM, Chris Caudle via time-nuts wrote:

I'd be impressed if I were your neighbor.

But then...

When I got my first munificent "new technology report" award from JPL
($300 - they don't do it any more) I was in a quandary of what to get. 
A work colleague said "get yourself a surplus GPSDO.. how many things do
you have at home that are accurate to 1 part in 10^12?"

The die was cast.

Rick,

So, optical pumping has several benefits.

First of all, rather than selection magnet A, you pump all atoms into
the same state. This means that rather than bending half of them away
from the rest of the beam, they progress. This doubles the beam flow,
improving the S/N. You can then choose to change the rate of cesium to
make it last longer or get the improved quality. The actual numbers [1]
is that 22% is in clock transition rather than 7% of total atoms, so
that's an 3 times larger amount.

Similarly you replace the B magnet, but that just simplifies the device.

Also, the ionization and masspectrometer is replaced. Any issues in
ionization gets compensated, and you rather use flourescence detection.

The downside is that one has to operate the lasers such that they
survive long-term. So you traded problems. Then again, these lasers sit
outside of the physical package, so that is easier to manage.

None of these things is a significant step forward, but a step forward.
You get somewhat better performance.

That's at least how I understand it. Oscilloquartz have built a
commercial optical cesium, and it has been shipped.

[1] "Optically pumped small cesium beam standards: a status report".
https://tf.nist.gov/general/pdf/732.pdf

Cheers,
Magnus

On 2023-06-13 20:24, Richard Karlquist via time-nuts wrote:

Salut!

Collecting a few replies in a single mail to not clutter the mailinglist
unnecessarily.

On Tue, 13 Jun 2023 16:13:13 +0000
Tom Knox via time-nuts time-nuts@lists.febo.com wrote:

Microchip has been working on a trapped ytterbium microwave ion clock
for some time now. It's basically the same principle as the DSAC
that has been mentioned here several times, but using ytterbium instead
of mercury, which gives a longer ion life time (Yb+ is much less reactive
than Hg+). Because there is also no easy way to make a ytterbium lamp,
they have to use a laser for interogation instead, which complicates
things a little bit in terms of production. But the biggest advantage
of ytterbium ion clocks over mercury ion clocks is that ytterbium has
a cycling transition. Which means that one can probe the same atom
multiple times with a laser to see in which state it is, without
destroying the state. Which gives ytterbium a much higher photon
efficiency and thus lower short term noise.

Current prototypes have a short term stability of 3e-12 and a flicker
frequency floor of 5e-15. Because they contain buffer gas for cooling
of the ions, there is a slow drift, but they haven't published any
data on that so far.

It will still take a few years until we see ytterbium ion microwave
clocks on the market, though. They still struggle with quite a few
technical problems, one of which is laser reliability.

On Tue, 13 Jun 2023 11:24:17 -0700
Richard Karlquist via time-nuts time-nuts@lists.febo.com wrote:

Oscilloquartz did that. Appartently, according to the chief engineer,
everyone in the industry told them that it wouldn't be feasible to
do an optically pumped Cs beam standard, due to longgevity of lasers.
Yes, it took them a few years to get it done but it now works. The
imporvement in short term stability is quite significant. Long term
is a bit better than the 5071, but the data I saw was a few years ago
where it was still just a few prototypes, so I am not sure whether
this data is correct. I haven't seen any recent data yet.

On Tue, 13 Jun 2023 19:16:06 +0000
Ed Marciniak via time-nuts time-nuts@lists.febo.com wrote:

Trapped ion microwave clocks are already on the horizon, as I wrote above.
It is also likely that we will see optical clocks in a small form factor
soon (next 10-15 years). There has been quite a bit of research in that
area, especially in terms of shrinking the physics package (e.g. Opticlocks
Yb ion trap is tiny [1]) and some of these systems are already very compact
(e.g. the university of Wuhan Ca+ ion clock [2,3])

This is more difficult than it seems. Most of the spent Cs ends up
either coating the hot wire detector or the vacuum pump. For the Cs
to migrate back one would need to heat up the whole tube, including
the vacuum pump to the point the Cs boils off and cool the oven down
enough that everything condenses there reasonably fast. This would be
an increadibly slow process (stochastics is not nice when you want
to get things done fast) and would also release all the stuff you don't
want in the vacuum tube that the vacuum pump gathered. Sending the
whole clock in for a tube replacement would be still much quicker and
less problematic.

On Tue, 13 Jun 2023 08:23:00 -0700
Tom Van Baak via time-nuts time-nuts@lists.febo.com wrote:

OLED, due to it being based on exciting organic molecules to the point
they radiate light, still does not have the lifetime that we would expect
of an atomic clock. OLED barely works for smart phones, where the expected
product life time is less than 5 years and with an on-time of less than 20%
(probably closer tro 5%). And we still notice a visible degradation of the
OLED during that short period. LCD on the other hand has easily a life time
of 20 years with little degradation, most of which can be compensated with
increasing the applied voltage. LEDs on the other hand, have almost infinite
lifetime if operated at less than 20% or rated current, which still makes
them blindingly bright, these days.

			Attila Kinali

[1] "Die optische Atomuhr geht in die Anwendung", by Biethahn and Berger,
2019
https://doi.org/10.1002/vipr.201900730

[2] "A compact, transportable single-ion optical clock with 7.8e-17
systematic uncertainty", by Cao et al. 2017
https://doi.org/10.1007/s00340-017-6671-5

[3] "A compact, transportable optical clock with uncertainty and its
absolute frequency measurement", by Cao et al.
https://doi.org/10.1063/5.0079432
(see suplementarry material for size of the whole system)

--
In science if you know what you are doing you should not be doing it.
In engineering if you do not know what you are doing you should not be doing it.
-- Richard W. Hamming, The Art of Doing Science and Engineering

Hi

The 1008 series passive hydrogen masers are in the same rough price range as the 5071.
Would you be be more impressed by your neighbor having one than the other? :)

I suspect one of the reasons prices don’t get published is that some (but certainly not all)
folks do indeed make a cost based decision between the two. The “which is best” debate
goes back at least into the 1980’s. There are applications that either one just might do
fine in.

The 5071 and 1008 do most certainly go into labs, however they are not the “best of the
best of the best”. Folks at PTB and NIST go to other devices when they are after “the best”.
These are production boxes that go a lot of obscure places to do this and that.

Some form of “super machine” that combined the long term stability of the 5071 with the
short term stability of a maser (passive or maybe even active) and came in roughly
the same in terms of  cost, size, proven performance (on production units), and tube life
as the 5071, would be a game changer.

That’s long list (without hard numbers for each of the points). It is the kind of list the next
generation probably needs to target to fully displace the current generation of devices.

Bob

Bob Camp via time-nuts writes:

What about shock and vibration sensitivity ?

I keep hearing about optical clocks which drop lock if a door is
slammed somewhere in the building ?

--
Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG        | TCP/IP since RFC 956
FreeBSD committer      | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

On Wed, 14 Jun 2023 09:30:20 -0500
Bob Camp via time-nuts time-nuts@lists.febo.com wrote:

While prices are not published, they aren't really secret either. If you ask at
conferences, you'll be told the price of any atomic clock you are interested in.
Even I, who is not buying any of these, have learned the prices of most of the
major used atomic clocks over the years.

We already have that. The SpectraDynamics cRb-Clock cold Rubidium clock delivers
the short term stability of a passive hydrogen maser with a flicker frequency
floor 3e-15 and no drift. It costs a little bit more than a 5071, though, but
it's also a more complex machine with lower production volume.

On Thu, 15 Jun 2023 05:40:52 +0000
Poul-Henning Kamp via time-nuts time-nuts@lists.febo.com wrote:

The optical system is pretty sensitive to vibration, but we are talking about
stabilities beyond 1e-15. Even a AHM will exhibit problems if you slam a door
somewhere in the building hard enough that an optical clock would unlock.

That said, one of the problems of why optical atomic clocks are so sensitive
is, because they are prototypes built on a breadboard. There is a lot that
can be affected by vibrations. Especially the early models suffered a lot
from that. Today, it's much better and people know which parts need to be
specially handled to ensure that they don't unlock because of a door slaming.
But vibration and even noise is still a major factor of instability in optical
clocks.

		Attila Kinali

--
The driving force behind research is the question: "Why?"
There are things we don't understand and things we always
wonder about. And that's why we do research.
-- Kobayashi Makoto

The Spectradynamic cRB not only has amazing specs, but is in my humble opinion is a piece of art when you look at build quality, overall engineering, not to mention performance. And although about twice the price of a 5071A I think once the cost of ownership is added it may prove more affordable in the long term.
I think this was a collaboration between, Spectradynamics, DARPA, NIST, and perhaps additional parties.
An interesting side note, Sepctradynamics was founded by Franklin Ascarrunz and Craig Nelson, And as many of you know Craig left SDI to work at NIST with the Phase Noise Measurement Group where his amazing contributions to the field speak for themself.
Cheers;
Tom Knox
SR Test and Measurement Engineer
Phoenix Research
4870 Meredith Way Apt 102
Boulder, Co 80303
Formerly of:
357 Fox Lane
Superior Co 80027
303-554-0307
actast@hotmail.com

https://www.thedenverchannel.com/news/marshall-fire/superior-man-moving-forward-after-losing-dream-research-lab-during-marshall-fire

"Peace is not the absence of violence, but the presence of Justice" Both MLK and Albert Einstein

From: Attila Kinali via time-nuts time-nuts@lists.febo.com
Sent: Thursday, June 15, 2023 12:30 AM
To: Discussion of precise time and frequency measurement time-nuts@lists.febo.com
Cc: Attila Kinali attila@kinali.ch
Subject: [time-nuts] Re: 5071B

On Wed, 14 Jun 2023 09:30:20 -0500
Bob Camp via time-nuts time-nuts@lists.febo.com wrote:

While prices are not published, they aren't really secret either. If you ask at
conferences, you'll be told the price of any atomic clock you are interested in.
Even I, who is not buying any of these, have learned the prices of most of the
major used atomic clocks over the years.

We already have that. The SpectraDynamics cRb-Clock cold Rubidium clock delivers
the short term stability of a passive hydrogen maser with a flicker frequency
floor 3e-15 and no drift. It costs a little bit more than a 5071, though, but
it's also a more complex machine with lower production volume.

On Thu, 15 Jun 2023 05:40:52 +0000
Poul-Henning Kamp via time-nuts time-nuts@lists.febo.com wrote:

The optical system is pretty sensitive to vibration, but we are talking about
stabilities beyond 1e-15. Even a AHM will exhibit problems if you slam a door
somewhere in the building hard enough that an optical clock would unlock.

That said, one of the problems of why optical atomic clocks are so sensitive
is, because they are prototypes built on a breadboard. There is a lot that
can be affected by vibrations. Especially the early models suffered a lot
from that. Today, it's much better and people know which parts need to be
specially handled to ensure that they don't unlock because of a door slaming.
But vibration and even noise is still a major factor of instability in optical
clocks.

                    Attila Kinali

--
The driving force behind research is the question: "Why?"
There are things we don't understand and things we always
wonder about. And that's why we do research.
-- Kobayashi Makoto

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com

Hi Poul-Henning,

On 2023-06-15 07:40, Poul-Henning Kamp via time-nuts wrote:

You should not confuse the optical cesiums with optical clocks. Quite
different spieces. The optical cesiums is still an RF frequency device,
it is just that magnetics and detection got an optical upgrade.
Performance wise they are still in the neighborhood of the classical
cesium beams, compared to the optical transition clocks which is way
below either of the beam setups, or for that matter the gravity folded
beam of fountains.

Cheers,
Magnus