RK
Richard Karlquist
Thu, Jun 8, 2023 8:53 PM
I LOVE the title! "Keeping time from becoming obsolete"
https://www.ion.org/publications/abstract.cfm?articleID=18692
Rick Karlquist
N6RK
I LOVE the title! "Keeping time from becoming obsolete"
https://www.ion.org/publications/abstract.cfm?articleID=18692
---
Rick Karlquist
N6RK
BG
Bruce Griffiths
Fri, Jun 9, 2023 5:03 AM
On 09/06/2023 04:38 NZST Leo Ahluwalia via time-nuts time-nuts@lists.febo.com wrote:
Hi Stephen, I appreciate the advice, and while glass-blowing isn't
something I've had much experience with, making the glass package
definitely sounds like a fun challenge.
Thanks, Leo
On Wed, Jun 7, 2023 at 8:23 AM Stephen C. Menasian via time-nuts <
time-nuts@lists.febo.com> wrote:
Leo,
This is a complex, but interesting, project. The electronics/microwave
part of the project is fairly straightforward and is best left for later
phases of the project. The interesting part of the project is the
"physics" package, which I refer to as "optical pumping". My experience
in this area is a bit dated (5-6 decades ago), when my undergraduate and
PhD work was centered on optical pumping of Rb, Na and Cs atoms as well as
H2+ and Hg+ ions. A lot has changed since then; in particular, many
refinements have been made to create practical miniaturized Rb based
systems suitable for commercial time standards; I am not current on these
changes.
Your first task would be to establish and demonstrate optical pumping of
Rb87 atoms. For this, you would need, at a miniumum:
- some pure Rb87
- a glass blowing setup (and some skill)
- A selection of inert gasses (at least including Ar)
- Light source (Rb discharge was used then with a circular polarizer;
intensity pumping via Rb89 (I believe) is often used now.
Infrared lasers look very interesting to me.
- A low noise light detector (I used photomultipliers - many more modern
solid state possibilities exist now.
- a uniform magnetic field (Helmholtz coils or solenoid) and magnetic
shielding.
- A means of controlling cell temperature (Rb vapor pressure)
- A bit of electronics, including RF power for the lamp. Note that a
noisy lamp discharge will mask the desired signal.
You should start with the Zeeman transitions, which are much easier to
observe and don't require microwave hardware. If you can't see a Zeeman
transition, there is no hope for the hyperfine transition. Getting
collisional disorientation down to a low enough level might involve
experimentation with various buffer gas formulations and pressures and
cell wall coatings (we used a very thin teflon film).
If you get to the point where you can see the Zeeman transitions, you
will have accomplished and learned a lot. With a little more effort, you
should be able to see the hyperfine transition.
Good Luck!!!
Stephen
On Tue, 6 Jun 2023 15:25:47 -0400
Leo Ahluwalia via time-nuts time-nuts@lists.febo.com wrote:
Hello, my name is Leo, and I was wondering about the feasibility of
creating a simple rubidium atomic clock at home, and good places to
source parts for this sort of project. I was also wondering what
instruments and specialized knowledge would be required depending on
how pre-built the parts are, for example, the prerequisite knowledge
for creating PLL(s) for both frequency division to provide an output
and also to modulate the input of the microwave oscillator. Any good
resources or PDFs would be greatly appreciated, as I am very new to
frequency analysis and phase manipulation in general. I was also hoping
to keep the cost of the project soft-line below 500$, though that would
be assuming a decent level of precision and already possessing basic
equipment (oscilloscope, multimeter, etc…). Safety is also a major
concern, as I know while the intensity of the EM waves involved is low,
the power source may or may not be. This is all of course assuming a
basic design, where my assumption is that it will involve the
microwaves being shot at a rubidium vapor cell which is directed
towards a photodetector. This would then be connected up to the PLL and
circuitry to both provide a stable standard while also modulating the
microwave oscillator to offset any external environmental factors. I
don't have a clear vision of what would truly be the best design for
both simplicity and cost, though this is what I've found to be a common
design in what I've looked at online.
Thanks, Leo
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Thorlabs make Rubidium 87 absorption cells.
They recommend borosilicate glass rather than fused silica.
Borosilicate glass is more resistant to chemical attack by alkali metals than fuse quartz.
Thorlabs also make custom absorption cells but the shipping overseas is very expensive due to the 49 billion year half-life of Rb87.
The Australians (https://findanexpert.unimelb.edu.au/scholarlywork/315753-linewidths-below-100-khz-with-external-cavity-diode-lasers) roll their own ECDLs for Rubidium absorption line locking.
Bruce
> On 09/06/2023 04:38 NZST Leo Ahluwalia via time-nuts <time-nuts@lists.febo.com> wrote:
>
>
> Hi Stephen, I appreciate the advice, and while glass-blowing isn't
> something I've had much experience with, making the glass package
> definitely sounds like a fun challenge.
>
> Thanks, Leo
>
> On Wed, Jun 7, 2023 at 8:23 AM Stephen C. Menasian via time-nuts <
> time-nuts@lists.febo.com> wrote:
>
> > Leo,
> >
> > This is a complex, but interesting, project. The electronics/microwave
> > part of the project is fairly straightforward and is best left for later
> > phases of the project. The interesting part of the project is the
> > "physics" package, which I refer to as "optical pumping". My experience
> > in this area is a bit dated (5-6 decades ago), when my undergraduate and
> > PhD work was centered on optical pumping of Rb, Na and Cs atoms as well as
> > H2+ and Hg+ ions. A lot has changed since then; in particular, many
> > refinements have been made to create practical miniaturized Rb based
> > systems suitable for commercial time standards; I am not current on these
> > changes.
> >
> > Your first task would be to establish and demonstrate optical pumping of
> > Rb87 atoms. For this, you would need, at a miniumum:
> >
> > 1) some pure Rb87
> > 2) a glass blowing setup (and some skill)
> > 3) A selection of inert gasses (at least including Ar)
> > 4) Light source (Rb discharge was used then with a circular polarizer;
> > intensity pumping via Rb89 (I believe) is often used now.
> > Infrared lasers look very interesting to me.
> > 5) A low noise light detector (I used photomultipliers - many more modern
> > solid state possibilities exist now.
> > 6) a uniform magnetic field (Helmholtz coils or solenoid) and magnetic
> > shielding.
> > 7) A means of controlling cell temperature (Rb vapor pressure)
> > 8) A bit of electronics, including RF power for the lamp. Note that a
> > noisy lamp discharge will mask the desired signal.
> >
> > You should start with the Zeeman transitions, which are much easier to
> > observe and don't require microwave hardware. If you can't see a Zeeman
> > transition, there is no hope for the hyperfine transition. Getting
> > collisional disorientation down to a low enough level might involve
> > experimentation with various buffer gas formulations and pressures and
> > cell wall coatings (we used a very thin teflon film).
> >
> > If you get to the point where you can see the Zeeman transitions, you
> > will have accomplished and learned a lot. With a little more effort, you
> > should be able to see the hyperfine transition.
> >
> > Good Luck!!!
> >
> > Stephen
> >
> >
> >
> >
> >
> > On Tue, 6 Jun 2023 15:25:47 -0400
> > Leo Ahluwalia via time-nuts <time-nuts@lists.febo.com> wrote:
> >
> > > Hello, my name is Leo, and I was wondering about the feasibility of
> > > creating a simple rubidium atomic clock at home, and good places to
> > > source parts for this sort of project. I was also wondering what
> > > instruments and specialized knowledge would be required depending on
> > > how pre-built the parts are, for example, the prerequisite knowledge
> > > for creating PLL(s) for both frequency division to provide an output
> > > and also to modulate the input of the microwave oscillator. Any good
> > > resources or PDFs would be greatly appreciated, as I am very new to
> > > frequency analysis and phase manipulation in general. I was also hoping
> > > to keep the cost of the project soft-line below 500$, though that would
> > > be assuming a decent level of precision and already possessing basic
> > > equipment (oscilloscope, multimeter, etc…). Safety is also a major
> > > concern, as I know while the intensity of the EM waves involved is low,
> > > the power source may or may not be. This is all of course assuming a
> > > basic design, where my assumption is that it will involve the
> > > microwaves being shot at a rubidium vapor cell which is directed
> > > towards a photodetector. This would then be connected up to the PLL and
> > > circuitry to both provide a stable standard while also modulating the
> > > microwave oscillator to offset any external environmental factors. I
> > > don't have a clear vision of what would truly be the best design for
> > > both simplicity and cost, though this is what I've found to be a common
> > > design in what I've looked at online.
> > >
> > >
> > > Thanks, Leo
> > > _______________________________________________
> > > time-nuts mailing list -- time-nuts@lists.febo.com
> > > To unsubscribe send an email to time-nuts-leave@lists.febo.com
> > _______________________________________________
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe send an email to time-nuts-leave@lists.febo.com
> _______________________________________________
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe send an email to time-nuts-leave@lists.febo.com
AK
Attila Kinali
Fri, Jun 9, 2023 7:19 AM
Moin moin!
Well, it's not quite announced yet. Microsemi can still not officially
confirm or deny the existense of the B model. But they talk a lot
about the 5071 "black edition" :-)
On Thu, 08 Jun 2023 13:53:16 -0700
Richard Karlquist via time-nuts time-nuts@lists.febo.com wrote:
I talked a little bit with Dave Chandler at IFCS/EFTF about this.
The changes were mostly for RoHS and EoL reasons. I.e. replace
all the components that didn't meet RoHS criteria and replace
all components that they couldn't get anymore. They tried to
keep the circuits as close to the original design as possible.
The biggest problem they faced was that all of the original
designers and engineers have been long retired and quite a
few had passed away. Quite a bit of the old documentation did
not make sense or did not match what was actually being produced.
Tracking down the old designers to ask them questions was a major
part of the redesign process.
The first test devices seem to work fine and have the same
performance as the A model. Though the long term tests are
still missing. We should hear more about this in the
coming months.
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
Moin moin!
Well, it's not quite announced yet. Microsemi can still not officially
confirm or deny the existense of the B model. But they talk a lot
about the 5071 "black edition" :-)
On Thu, 08 Jun 2023 13:53:16 -0700
Richard Karlquist via time-nuts <time-nuts@lists.febo.com> wrote:
> I LOVE the title! "Keeping time from becoming obsolete"
>
> https://www.ion.org/publications/abstract.cfm?articleID=18692
I talked a little bit with Dave Chandler at IFCS/EFTF about this.
The changes were mostly for RoHS and EoL reasons. I.e. replace
all the components that didn't meet RoHS criteria and replace
all components that they couldn't get anymore. They tried to
keep the circuits as close to the original design as possible.
The biggest problem they faced was that all of the original
designers and engineers have been long retired and quite a
few had passed away. Quite a bit of the old documentation did
not make sense or did not match what was actually being produced.
Tracking down the old designers to ask them questions was a major
part of the redesign process.
The first test devices seem to work fine and have the same
performance as the A model. Though the long term tests are
still missing. We should hear more about this in the
coming months.
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
PK
Poul-Henning Kamp
Fri, Jun 9, 2023 8:11 AM
Attila Kinali via time-nuts writes:
The changes were mostly for RoHS and EoL reasons. I.e. replace
all the components that didn't meet RoHS criteria and replace
all components that they couldn't get anymore. They tried to
keep the circuits as close to the original design as possible.
The biggest problem they faced was that all of the original
designers and engineers have been long retired and quite a
few had passed away. Quite a bit of the old documentation did
not make sense or did not match what was actually being produced.
Tracking down the old designers to ask them questions was a major
part of the redesign process.
This is pretty parallel to the process Agilent went through to
life-extend the HP3458A 8.5 digit DVM.
--
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.
--------
Attila Kinali via time-nuts writes:
> The changes were mostly for RoHS and EoL reasons. I.e. replace
> all the components that didn't meet RoHS criteria and replace
> all components that they couldn't get anymore. They tried to
> keep the circuits as close to the original design as possible.
>
> The biggest problem they faced was that all of the original
> designers and engineers have been long retired and quite a
> few had passed away. Quite a bit of the old documentation did
> not make sense or did not match what was actually being produced.
> Tracking down the old designers to ask them questions was a major
> part of the redesign process.
This is pretty parallel to the process Agilent went through to
life-extend the HP3458A 8.5 digit DVM.
--
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.
MD
Magnus Danielson
Fri, Jun 9, 2023 10:27 AM
Hi Leo,
The physical package is wrapped such that essentially no ambient light
comes in, the other design requirements drive the design that way
anyway, both magnetic shielding and RF cavity, so I consider there being
no need to do additional dim outs.
You do not want to dim the photodetector itself fromt he light through
rubidium. You already face a signal to noise problem there that will
affect the stability.
The Varnier and Audoin "The Quantum Physics of Atomic Frequency
Standards" Vol 1 and 2 is very relevant too. These books are somewhat
older, but great in depth reference. The Riley Rubidium Frequency
Standard Primer is more modern, gives great orientation, but for some
aspects do not go into more depth than necessary, which is fine, it is
an excellent starting point that cover most issues, so read that first,
and then dwell into Varnier and Audoin.
Cheers,
Magnus
On 2023-06-08 18:45, Leo Ahluwalia via time-nuts wrote:
Hi Magnus, I'll definitely have to take a look at the resources Tom, zfe,
and Andy sent my way. To my theoretical knowledge, the attenuation of the
photo-detector is a possibility - to avoid having to dim out the room where
the apparatus is contained - and I was wondering if you or anyone else had
experience working with something of that nature. I appreciate the advice
on the setup, it definitely cleared up some things for me.
On Wed, Jun 7, 2023 at 9:27 PM Magnus Danielson via time-nuts <
time-nuts@lists.febo.com> wrote:
Hi Leo,
So, the setup is very straight forward. You put the Rb-lamp, the filter,
the Rb resonance cell all lined up in a straight path and at the far end
of that you have a photo-detector. The resonance cell you want to keep
magnetically shielded, which is typically done by one or more (I have
clocks with 3) layers of mu-metal. You have a coil, called C-field coil,
through which a DC current creates a magnetic field that separates the 5
Rb resonances so that only the (1,0)->(2,0) absorption occurs, which is
detected by a thad lower intensity of the pump light.
Look at Tom's email and I strongly suggest you get "Rubidium Frequency
Standard Primer" of William J. Riley which has a lot of info in it
covering a lot of the things that goes into it. This includes a lot of
photo of the actual inner parts of the rubidium clocks. There is more
material to gather, but already that book will answer a lot of things
for you and summarizes a lot of stuff in a very condensed and straight
forward way.
Cheers,
Magnus
On 2023-06-08 00:38, Leo Ahluwalia via time-nuts wrote:
I appreciate all of the help so far, and assuming the procurement of a
rubidium vapour cell and rubidium lamp (and of course all the other
components), I was wondering how exactly the optical pumping setup should
be achieved (to make sure all the components are "hooked up" so to
speak),
and whether there was already a standard way of achieving it along with
the
installation of the magnetic shielding?
On Wed, Jun 7, 2023 at 6:27 PM Bruce Griffiths via time-nuts <
time-nuts@lists.febo.com> wrote:
That just leaves the Rubidium lamp.
An ECDL (external cavity diode laser) locked to the appropriate Rubidium
transition is much easier to build. There are several ECDL designs in
the
literature. Mostly these are Littrow designs. A Cateye resonator design
is
another option. All the components required are readily availble.
VCSEL's should be avoided as those without polarisation mode
stabilisation
gratings on the output face randomly mode hop between a pair or
orthogonally polarised modes.
A well designed but relatively simple ECDL can have a much narrower line
width than a typical DFB laser.
Bruce
On 08/06/2023 06:37 NZST djl via time-nuts time-nuts@lists.febo.com
wrote:
The Rb capsules are available on ebay, eg: 124012486501
the classblowing part is done?
On 2023-06-07 07:50, Richard (Rick) Karlquist via time-nuts wrote:
On 6/7/2023 5:03 AM, Stephen C. Menasian via time-nuts wrote:
- some pure Rb87
- a glass blowing setup (and some skill)
- A selection of inert gasses (at least including Ar)
- Light source (Rb discharge was used then with a circular
polarizer;
At HP we had really skilled glass blowers, with specific experience in
making Rb glassware. We had to use an exotic grade of glass that was
only one step removed from fused quartz. It had a part number that I
don't remember. Very difficult to work with.
The Rb lamp (one of three pieces of glassware) is very tricky to work
with. We used a resonant coil driven at 95 MHz at several watts.
The trick is to "strike" the plasma and make the lamp light up;
you can at least see visible light when that happens. I spent a
lot of time fooling with it. We never got it to work as
well as the 5065 lamp.
BTW, one of the Rb isotopes is slightly radioactive. Might be
hard to get as a hobbyist due to regulations. The physicist I
sat next to had a tank of it illegally stored in his cubicle.
Rick
N6RK
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
"It's always something."
Roseanne Rosannadanna
----------------------"
Dr. Don Latham AJ7LL
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304
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Hi Leo,
The physical package is wrapped such that essentially no ambient light
comes in, the other design requirements drive the design that way
anyway, both magnetic shielding and RF cavity, so I consider there being
no need to do additional dim outs.
You do not want to dim the photodetector itself fromt he light through
rubidium. You already face a signal to noise problem there that will
affect the stability.
The Varnier and Audoin "The Quantum Physics of Atomic Frequency
Standards" Vol 1 and 2 is very relevant too. These books are somewhat
older, but great in depth reference. The Riley Rubidium Frequency
Standard Primer is more modern, gives great orientation, but for some
aspects do not go into more depth than necessary, which is fine, it is
an excellent starting point that cover most issues, so read that first,
and then dwell into Varnier and Audoin.
Cheers,
Magnus
On 2023-06-08 18:45, Leo Ahluwalia via time-nuts wrote:
> Hi Magnus, I'll definitely have to take a look at the resources Tom, zfe,
> and Andy sent my way. To my theoretical knowledge, the attenuation of the
> photo-detector is a possibility - to avoid having to dim out the room where
> the apparatus is contained - and I was wondering if you or anyone else had
> experience working with something of that nature. I appreciate the advice
> on the setup, it definitely cleared up some things for me.
>
> - Leo
>
> On Wed, Jun 7, 2023 at 9:27 PM Magnus Danielson via time-nuts <
> time-nuts@lists.febo.com> wrote:
>
>> Hi Leo,
>>
>> So, the setup is very straight forward. You put the Rb-lamp, the filter,
>> the Rb resonance cell all lined up in a straight path and at the far end
>> of that you have a photo-detector. The resonance cell you want to keep
>> magnetically shielded, which is typically done by one or more (I have
>> clocks with 3) layers of mu-metal. You have a coil, called C-field coil,
>> through which a DC current creates a magnetic field that separates the 5
>> Rb resonances so that only the (1,0)->(2,0) absorption occurs, which is
>> detected by a thad lower intensity of the pump light.
>>
>> Look at Tom's email and I strongly suggest you get "Rubidium Frequency
>> Standard Primer" of William J. Riley which has a lot of info in it
>> covering a lot of the things that goes into it. This includes a lot of
>> photo of the actual inner parts of the rubidium clocks. There is more
>> material to gather, but already that book will answer a lot of things
>> for you and summarizes a lot of stuff in a very condensed and straight
>> forward way.
>>
>> Cheers,
>> Magnus
>>
>> On 2023-06-08 00:38, Leo Ahluwalia via time-nuts wrote:
>>> I appreciate all of the help so far, and assuming the procurement of a
>>> rubidium vapour cell and rubidium lamp (and of course all the other
>>> components), I was wondering how exactly the optical pumping setup should
>>> be achieved (to make sure all the components are "hooked up" so to
>> speak),
>>> and whether there was already a standard way of achieving it along with
>> the
>>> installation of the magnetic shielding?
>>>
>>> - Leo
>>>
>>> On Wed, Jun 7, 2023 at 6:27 PM Bruce Griffiths via time-nuts <
>>> time-nuts@lists.febo.com> wrote:
>>>
>>>> That just leaves the Rubidium lamp.
>>>> An ECDL (external cavity diode laser) locked to the appropriate Rubidium
>>>> transition is much easier to build. There are several ECDL designs in
>> the
>>>> literature. Mostly these are Littrow designs. A Cateye resonator design
>> is
>>>> another option. All the components required are readily availble.
>>>> VCSEL's should be avoided as those without polarisation mode
>> stabilisation
>>>> gratings on the output face randomly mode hop between a pair or
>>>> orthogonally polarised modes.
>>>> A well designed but relatively simple ECDL can have a much narrower line
>>>> width than a typical DFB laser.
>>>>
>>>> Bruce
>>>>> On 08/06/2023 06:37 NZST djl via time-nuts <time-nuts@lists.febo.com>
>>>> wrote:
>>>>> The Rb capsules are available on ebay, eg: 124012486501
>>>>> the classblowing part is done?
>>>>>
>>>>> On 2023-06-07 07:50, Richard (Rick) Karlquist via time-nuts wrote:
>>>>>> On 6/7/2023 5:03 AM, Stephen C. Menasian via time-nuts wrote:
>>>>>>
>>>>>>> 1) some pure Rb87
>>>>>>> 2) a glass blowing setup (and some skill)
>>>>>>> 3) A selection of inert gasses (at least including Ar)
>>>>>>> 4) Light source (Rb discharge was used then with a circular
>> polarizer;
>>>>>> At HP we had really skilled glass blowers, with specific experience in
>>>>>> making Rb glassware. We had to use an exotic grade of glass that was
>>>>>> only one step removed from fused quartz. It had a part number that I
>>>>>> don't remember. Very difficult to work with.
>>>>>>
>>>>>> The Rb lamp (one of three pieces of glassware) is very tricky to work
>>>>>> with. We used a resonant coil driven at 95 MHz at several watts.
>>>>>> The trick is to "strike" the plasma and make the lamp light up;
>>>>>> you can at least see visible light when that happens. I spent a
>>>>>> lot of time fooling with it. We never got it to work as
>>>>>> well as the 5065 lamp.
>>>>>>
>>>>>> BTW, one of the Rb isotopes is slightly radioactive. Might be
>>>>>> hard to get as a hobbyist due to regulations. The physicist I
>>>>>> sat next to had a tank of it illegally stored in his cubicle.
>>>>>>
>>>>>> Rick
>>>>>> N6RK
>>>>>> _______________________________________________
>>>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>>>> To unsubscribe send an email to time-nuts-leave@lists.febo.com
>>>>> ------------
>>>>> "It's always something."
>>>>> Roseanne Rosannadanna
>>>>> ----------------------"
>>>>> Dr. Don Latham AJ7LL
>>>>> PO Box 404, Frenchtown, MT, 59834
>>>>> VOX: 406-626-4304
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>>> To unsubscribe send an email to time-nuts-leave@lists.febo.com
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>> To unsubscribe send an email to time-nuts-leave@lists.febo.com
>>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe send an email to time-nuts-leave@lists.febo.com
>> _______________________________________________
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe send an email to time-nuts-leave@lists.febo.com
> _______________________________________________
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe send an email to time-nuts-leave@lists.febo.com
MD
Magnus Danielson
Fri, Jun 9, 2023 10:29 AM
Hi,
On 2023-06-09 10:11, Poul-Henning Kamp via time-nuts wrote:
Attila Kinali via time-nuts writes:
The changes were mostly for RoHS and EoL reasons. I.e. replace
all the components that didn't meet RoHS criteria and replace
all components that they couldn't get anymore. They tried to
keep the circuits as close to the original design as possible.
The biggest problem they faced was that all of the original
designers and engineers have been long retired and quite a
few had passed away. Quite a bit of the old documentation did
not make sense or did not match what was actually being produced.
Tracking down the old designers to ask them questions was a major
part of the redesign process.
This is pretty parallel to the process Agilent went through to
life-extend the HP3458A 8.5 digit DVM.
Well, considering the challenges in sourcing components and the fact
that 5071A has been runing a long time, there come a day when they have
to revamp it or replace it.
Cheers,
Magnus
Hi,
On 2023-06-09 10:11, Poul-Henning Kamp via time-nuts wrote:
> --------
> Attila Kinali via time-nuts writes:
>
>> The changes were mostly for RoHS and EoL reasons. I.e. replace
>> all the components that didn't meet RoHS criteria and replace
>> all components that they couldn't get anymore. They tried to
>> keep the circuits as close to the original design as possible.
>>
>> The biggest problem they faced was that all of the original
>> designers and engineers have been long retired and quite a
>> few had passed away. Quite a bit of the old documentation did
>> not make sense or did not match what was actually being produced.
>> Tracking down the old designers to ask them questions was a major
>> part of the redesign process.
> This is pretty parallel to the process Agilent went through to
> life-extend the HP3458A 8.5 digit DVM.
>
Well, considering the challenges in sourcing components and the fact
that 5071A has been runing a long time, there come a day when they have
to revamp it or replace it.
Cheers,
Magnus
LA
Leo Ahluwalia
Mon, Jun 12, 2023 6:21 PM
Hi Magnus, I appreciate the book suggestions, I'll have to take a look at
the primer and the books mentioned to hopefully get a clearer picture of
what my goals are. I hadn't realized that the package could be covered like
that (though I'm guessing post-construction for the most part), but it's
nice to hear that I won't have to set up a room or space for a dim-out.
I'll have to make sure to keep the timenuts posted once I've done some more
research.
Thanks, Leo
On Fri, Jun 9, 2023 at 8:08 AM Magnus Danielson via time-nuts <
time-nuts@lists.febo.com> wrote:
Hi Leo,
The physical package is wrapped such that essentially no ambient light
comes in, the other design requirements drive the design that way
anyway, both magnetic shielding and RF cavity, so I consider there being
no need to do additional dim outs.
You do not want to dim the photodetector itself fromt he light through
rubidium. You already face a signal to noise problem there that will
affect the stability.
The Varnier and Audoin "The Quantum Physics of Atomic Frequency
Standards" Vol 1 and 2 is very relevant too. These books are somewhat
older, but great in depth reference. The Riley Rubidium Frequency
Standard Primer is more modern, gives great orientation, but for some
aspects do not go into more depth than necessary, which is fine, it is
an excellent starting point that cover most issues, so read that first,
and then dwell into Varnier and Audoin.
Cheers,
Magnus
On 2023-06-08 18:45, Leo Ahluwalia via time-nuts wrote:
Hi Magnus, I'll definitely have to take a look at the resources Tom, zfe,
and Andy sent my way. To my theoretical knowledge, the attenuation of the
photo-detector is a possibility - to avoid having to dim out the room
the apparatus is contained - and I was wondering if you or anyone else
experience working with something of that nature. I appreciate the advice
on the setup, it definitely cleared up some things for me.
On Wed, Jun 7, 2023 at 9:27 PM Magnus Danielson via time-nuts <
time-nuts@lists.febo.com> wrote:
Hi Leo,
So, the setup is very straight forward. You put the Rb-lamp, the filter,
the Rb resonance cell all lined up in a straight path and at the far end
of that you have a photo-detector. The resonance cell you want to keep
magnetically shielded, which is typically done by one or more (I have
clocks with 3) layers of mu-metal. You have a coil, called C-field coil,
through which a DC current creates a magnetic field that separates the 5
Rb resonances so that only the (1,0)->(2,0) absorption occurs, which is
detected by a thad lower intensity of the pump light.
Look at Tom's email and I strongly suggest you get "Rubidium Frequency
Standard Primer" of William J. Riley which has a lot of info in it
covering a lot of the things that goes into it. This includes a lot of
photo of the actual inner parts of the rubidium clocks. There is more
material to gather, but already that book will answer a lot of things
for you and summarizes a lot of stuff in a very condensed and straight
forward way.
Cheers,
Magnus
On 2023-06-08 00:38, Leo Ahluwalia via time-nuts wrote:
I appreciate all of the help so far, and assuming the procurement of a
rubidium vapour cell and rubidium lamp (and of course all the other
components), I was wondering how exactly the optical pumping setup
be achieved (to make sure all the components are "hooked up" so to
and whether there was already a standard way of achieving it along with
installation of the magnetic shielding?
On Wed, Jun 7, 2023 at 6:27 PM Bruce Griffiths via time-nuts <
time-nuts@lists.febo.com> wrote:
That just leaves the Rubidium lamp.
An ECDL (external cavity diode laser) locked to the appropriate
transition is much easier to build. There are several ECDL designs in
literature. Mostly these are Littrow designs. A Cateye resonator
another option. All the components required are readily availble.
VCSEL's should be avoided as those without polarisation mode
gratings on the output face randomly mode hop between a pair or
orthogonally polarised modes.
A well designed but relatively simple ECDL can have a much narrower
width than a typical DFB laser.
Bruce
The Rb capsules are available on ebay, eg: 124012486501
the classblowing part is done?
On 2023-06-07 07:50, Richard (Rick) Karlquist via time-nuts wrote:
On 6/7/2023 5:03 AM, Stephen C. Menasian via time-nuts wrote:
- some pure Rb87
- a glass blowing setup (and some skill)
- A selection of inert gasses (at least including Ar)
- Light source (Rb discharge was used then with a circular
At HP we had really skilled glass blowers, with specific experience
making Rb glassware. We had to use an exotic grade of glass that
only one step removed from fused quartz. It had a part number that
don't remember. Very difficult to work with.
The Rb lamp (one of three pieces of glassware) is very tricky to
with. We used a resonant coil driven at 95 MHz at several watts.
The trick is to "strike" the plasma and make the lamp light up;
you can at least see visible light when that happens. I spent a
lot of time fooling with it. We never got it to work as
well as the 5065 lamp.
BTW, one of the Rb isotopes is slightly radioactive. Might be
hard to get as a hobbyist due to regulations. The physicist I
sat next to had a tank of it illegally stored in his cubicle.
Rick
N6RK
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
Hi Magnus, I appreciate the book suggestions, I'll have to take a look at
the primer and the books mentioned to hopefully get a clearer picture of
what my goals are. I hadn't realized that the package could be covered like
that (though I'm guessing post-construction for the most part), but it's
nice to hear that I won't have to set up a room or space for a dim-out.
I'll have to make sure to keep the timenuts posted once I've done some more
research.
Thanks, Leo
On Fri, Jun 9, 2023 at 8:08 AM Magnus Danielson via time-nuts <
time-nuts@lists.febo.com> wrote:
> Hi Leo,
>
> The physical package is wrapped such that essentially no ambient light
> comes in, the other design requirements drive the design that way
> anyway, both magnetic shielding and RF cavity, so I consider there being
> no need to do additional dim outs.
>
> You do not want to dim the photodetector itself fromt he light through
> rubidium. You already face a signal to noise problem there that will
> affect the stability.
>
> The Varnier and Audoin "The Quantum Physics of Atomic Frequency
> Standards" Vol 1 and 2 is very relevant too. These books are somewhat
> older, but great in depth reference. The Riley Rubidium Frequency
> Standard Primer is more modern, gives great orientation, but for some
> aspects do not go into more depth than necessary, which is fine, it is
> an excellent starting point that cover most issues, so read that first,
> and then dwell into Varnier and Audoin.
>
> Cheers,
> Magnus
>
> On 2023-06-08 18:45, Leo Ahluwalia via time-nuts wrote:
> > Hi Magnus, I'll definitely have to take a look at the resources Tom, zfe,
> > and Andy sent my way. To my theoretical knowledge, the attenuation of the
> > photo-detector is a possibility - to avoid having to dim out the room
> where
> > the apparatus is contained - and I was wondering if you or anyone else
> had
> > experience working with something of that nature. I appreciate the advice
> > on the setup, it definitely cleared up some things for me.
> >
> > - Leo
> >
> > On Wed, Jun 7, 2023 at 9:27 PM Magnus Danielson via time-nuts <
> > time-nuts@lists.febo.com> wrote:
> >
> >> Hi Leo,
> >>
> >> So, the setup is very straight forward. You put the Rb-lamp, the filter,
> >> the Rb resonance cell all lined up in a straight path and at the far end
> >> of that you have a photo-detector. The resonance cell you want to keep
> >> magnetically shielded, which is typically done by one or more (I have
> >> clocks with 3) layers of mu-metal. You have a coil, called C-field coil,
> >> through which a DC current creates a magnetic field that separates the 5
> >> Rb resonances so that only the (1,0)->(2,0) absorption occurs, which is
> >> detected by a thad lower intensity of the pump light.
> >>
> >> Look at Tom's email and I strongly suggest you get "Rubidium Frequency
> >> Standard Primer" of William J. Riley which has a lot of info in it
> >> covering a lot of the things that goes into it. This includes a lot of
> >> photo of the actual inner parts of the rubidium clocks. There is more
> >> material to gather, but already that book will answer a lot of things
> >> for you and summarizes a lot of stuff in a very condensed and straight
> >> forward way.
> >>
> >> Cheers,
> >> Magnus
> >>
> >> On 2023-06-08 00:38, Leo Ahluwalia via time-nuts wrote:
> >>> I appreciate all of the help so far, and assuming the procurement of a
> >>> rubidium vapour cell and rubidium lamp (and of course all the other
> >>> components), I was wondering how exactly the optical pumping setup
> should
> >>> be achieved (to make sure all the components are "hooked up" so to
> >> speak),
> >>> and whether there was already a standard way of achieving it along with
> >> the
> >>> installation of the magnetic shielding?
> >>>
> >>> - Leo
> >>>
> >>> On Wed, Jun 7, 2023 at 6:27 PM Bruce Griffiths via time-nuts <
> >>> time-nuts@lists.febo.com> wrote:
> >>>
> >>>> That just leaves the Rubidium lamp.
> >>>> An ECDL (external cavity diode laser) locked to the appropriate
> Rubidium
> >>>> transition is much easier to build. There are several ECDL designs in
> >> the
> >>>> literature. Mostly these are Littrow designs. A Cateye resonator
> design
> >> is
> >>>> another option. All the components required are readily availble.
> >>>> VCSEL's should be avoided as those without polarisation mode
> >> stabilisation
> >>>> gratings on the output face randomly mode hop between a pair or
> >>>> orthogonally polarised modes.
> >>>> A well designed but relatively simple ECDL can have a much narrower
> line
> >>>> width than a typical DFB laser.
> >>>>
> >>>> Bruce
> >>>>> On 08/06/2023 06:37 NZST djl via time-nuts <time-nuts@lists.febo.com
> >
> >>>> wrote:
> >>>>> The Rb capsules are available on ebay, eg: 124012486501
> >>>>> the classblowing part is done?
> >>>>>
> >>>>> On 2023-06-07 07:50, Richard (Rick) Karlquist via time-nuts wrote:
> >>>>>> On 6/7/2023 5:03 AM, Stephen C. Menasian via time-nuts wrote:
> >>>>>>
> >>>>>>> 1) some pure Rb87
> >>>>>>> 2) a glass blowing setup (and some skill)
> >>>>>>> 3) A selection of inert gasses (at least including Ar)
> >>>>>>> 4) Light source (Rb discharge was used then with a circular
> >> polarizer;
> >>>>>> At HP we had really skilled glass blowers, with specific experience
> in
> >>>>>> making Rb glassware. We had to use an exotic grade of glass that
> was
> >>>>>> only one step removed from fused quartz. It had a part number that
> I
> >>>>>> don't remember. Very difficult to work with.
> >>>>>>
> >>>>>> The Rb lamp (one of three pieces of glassware) is very tricky to
> work
> >>>>>> with. We used a resonant coil driven at 95 MHz at several watts.
> >>>>>> The trick is to "strike" the plasma and make the lamp light up;
> >>>>>> you can at least see visible light when that happens. I spent a
> >>>>>> lot of time fooling with it. We never got it to work as
> >>>>>> well as the 5065 lamp.
> >>>>>>
> >>>>>> BTW, one of the Rb isotopes is slightly radioactive. Might be
> >>>>>> hard to get as a hobbyist due to regulations. The physicist I
> >>>>>> sat next to had a tank of it illegally stored in his cubicle.
> >>>>>>
> >>>>>> Rick
> >>>>>> N6RK
> >>>>>> _______________________________________________
> >>>>>> time-nuts mailing list -- time-nuts@lists.febo.com
> >>>>>> To unsubscribe send an email to time-nuts-leave@lists.febo.com
> >>>>> ------------
> >>>>> "It's always something."
> >>>>> Roseanne Rosannadanna
> >>>>> ----------------------"
> >>>>> Dr. Don Latham AJ7LL
> >>>>> PO Box 404, Frenchtown, MT, 59834
> >>>>> VOX: 406-626-4304
> >>>>> _______________________________________________
> >>>>> time-nuts mailing list -- time-nuts@lists.febo.com
> >>>>> To unsubscribe send an email to time-nuts-leave@lists.febo.com
> >>>> _______________________________________________
> >>>> time-nuts mailing list -- time-nuts@lists.febo.com
> >>>> To unsubscribe send an email to time-nuts-leave@lists.febo.com
> >>>>
> >>> _______________________________________________
> >>> time-nuts mailing list -- time-nuts@lists.febo.com
> >>> To unsubscribe send an email to time-nuts-leave@lists.febo.com
> >> _______________________________________________
> >> time-nuts mailing list -- time-nuts@lists.febo.com
> >> To unsubscribe send an email to time-nuts-leave@lists.febo.com
> > _______________________________________________
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe send an email to time-nuts-leave@lists.febo.com
> _______________________________________________
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe send an email to time-nuts-leave@lists.febo.com
BS
Bob Stewart
Wed, Jun 14, 2023 10:47 PM
Adrian,
Are these what you were thinking of?
Rb High Precision Low Phase Noise Rubidium Tube Atomic Clock Soviet Ussr DIY #Z | eBay
|
|
|
| $99.97 | |
|
|
|
| |
Rb High Precision Low Phase Noise Rubidium Tube Atomic Clock Soviet Ussr...
Find many great new & used options and get the best deals for Rb High Precision Low Phase Noise Rubidium Tube At...
|
|
|
Bob
On Wednesday, June 7, 2023 at 01:14:43 PM CDT, Adrian Godwin via time-nuts <time-nuts@lists.febo.com> wrote:
I have seen glass rubidium capsules on ebay a couple of years ago. None at
the moment and they were possibly in Russia. They were just a glass capsule
- no surrounding components, not even a coil, but they weren't particularly
expensive,. Certainly not HP-spares expensive.
Is such a thing useful (to provide 'the hardest thing') for Leo's project
if they reappear ?
On Wed, Jun 7, 2023 at 1:26 PM Magnus Danielson via time-nuts <
time-nuts@lists.febo.com> wrote:
Hi,
I agree with Rick and was about to make more or less the same comment.
The glas package is the hardest thing to do, and there is also a certain
magic to mix the buffer gas just the right way to frequency compensate
the wall shift. Already there comes the aspect of knowing what wallshift
you will get, so you need reasonable reproduceability in both the glass
and pressure and mix in gases. To put that in other words, I am not THAT
crazy, yet.
Next level is the cavity you put the glas-ware into. The Q of that
resonator is not irrelevant, so you want to handle that.
There is a certain magic to the temperatures of the rubidium lamp and
that of the rubidium filter. This has consequences on how the physical
package is built. Some of this can be avoided today by using diodeds,
and that may even open up for avoiding the tuned resonator, but brings
in it's own set of issues.
Achievable engineering challenges, but maybe hard to do as a hobbyist.
The remaining temperature controls, FLL-lock of oscillator, synthesis
have become more and more achieveable over the years. That has become
hobbyist achieveable for sure.
However, just attempting to study up on a subject like this forces you
to learn alot, so even if you do not do a single soldering, you can have
improved your knowledge.
I would consider recycle an existing physical package that works and
make modern electronics for it. That should be plenty of challenges and
quite achieveable.
Cheers,
Magnus
On 2023-06-07 02:26, Richard Karlquist via time-nuts wrote:
In a former life, I was on the design team of a mini rubidium standard
at Hewlett-Packard. We built some working prototypes before it was
cancelled. It was going to have the model number 10816. I was the RF
person, but I worked very closely with the other team members.
Remembering what we had to go through to make "glassware", it is
inconceivable that you could do that as a "home brew" project. And this
was the same HP facility that already made the 5065 rubidium standard.
The best you could hope to do is to start with a commercial "physics
package" as we called it, and make your own electronics for it. Reading
books about how rubidium standards work, etc is fine, but again, you
can't home brew the glassware.
Rick Karlquist
N6RK
On 2023-06-06 15:39, Tom Van Baak via time-nuts wrote:
Hi Leo,
That sounds like a fun project. Here are some extremely informative
"Selection Criteria for Rubidium Frequency Standards"
by Bill Riley, 51 pages
Also read service manuals for commercial Rb products. Didier's site has
a nice collection. Search by product number (e.g., 5065a) or by title
(e.g., rubidium):
Hello, my name is Leo, and I was wondering about the feasibility of
creating a simple rubidium atomic clock at home, and good places to
parts for this sort of project. I was also wondering what instruments
specialized knowledge would be required depending on how pre-built the
parts are, for example, the prerequisite knowledge for creating PLL(s)
both frequency division to provide an output and also to modulate the
of the microwave oscillator. Any good resources or PDFs would be
appreciated, as I am very new to frequency analysis and phase
in general. I was also hoping to keep the cost of the project soft-line
below 500$, though that would be assuming a decent level of precision
already possessing basic equipment (oscilloscope, multimeter, etc...).
is also a major concern, as I know while the intensity of the EM waves
involved is low, the power source may or may not be. This is all of
assuming a basic design, where my assumption is that it will involve
microwaves being shot at a rubidium vapor cell which is directed
photodetector. This would then be connected up to the PLL and
both provide a stable standard while also modulating the microwave
oscillator to offset any external environmental factors. I don't have a
clear vision of what would truly be the best design for both
cost, though this is what I've found to be a common design in what I've
looked at online.
Thanks, Leo
Adrian,
Are these what you were thinking of?
Rb High Precision Low Phase Noise Rubidium Tube Atomic Clock Soviet Ussr DIY #Z | eBay
|
|
|
| $99.97 | |
|
|
|
| |
Rb High Precision Low Phase Noise Rubidium Tube Atomic Clock Soviet Ussr...
Find many great new & used options and get the best deals for Rb High Precision Low Phase Noise Rubidium Tube At...
|
|
|
Bob
On Wednesday, June 7, 2023 at 01:14:43 PM CDT, Adrian Godwin via time-nuts <time-nuts@lists.febo.com> wrote:
I have seen glass rubidium capsules on ebay a couple of years ago. None at
the moment and they were possibly in Russia. They were just a glass capsule
- no surrounding components, not even a coil, but they weren't particularly
expensive,. Certainly not HP-spares expensive.
Is such a thing useful (to provide 'the hardest thing') for Leo's project
if they reappear ?
On Wed, Jun 7, 2023 at 1:26 PM Magnus Danielson via time-nuts <
time-nuts@lists.febo.com> wrote:
> Hi,
>
> I agree with Rick and was about to make more or less the same comment.
>
> The glas package is the hardest thing to do, and there is also a certain
> magic to mix the buffer gas just the right way to frequency compensate
> the wall shift. Already there comes the aspect of knowing what wallshift
> you will get, so you need reasonable reproduceability in both the glass
> and pressure and mix in gases. To put that in other words, I am not THAT
> crazy, yet.
>
> Next level is the cavity you put the glas-ware into. The Q of that
> resonator is not irrelevant, so you want to handle that.
>
> There is a certain magic to the temperatures of the rubidium lamp and
> that of the rubidium filter. This has consequences on how the physical
> package is built. Some of this can be avoided today by using diodeds,
> and that may even open up for avoiding the tuned resonator, but brings
> in it's own set of issues.
>
> Achievable engineering challenges, but maybe hard to do as a hobbyist.
> The remaining temperature controls, FLL-lock of oscillator, synthesis
> have become more and more achieveable over the years. That has become
> hobbyist achieveable for sure.
>
> However, just *attempting* to study up on a subject like this forces you
> to learn alot, so even if you do not do a single soldering, you can have
> improved your knowledge.
>
> I would consider recycle an existing physical package that works and
> make modern electronics for it. That should be plenty of challenges and
> quite achieveable.
>
> Cheers,
> Magnus
>
> On 2023-06-07 02:26, Richard Karlquist via time-nuts wrote:
> > In a former life, I was on the design team of a mini rubidium standard
> > at Hewlett-Packard. We built some working prototypes before it was
> > cancelled. It was going to have the model number 10816. I was the RF
> > person, but I worked very closely with the other team members.
> > Remembering what we had to go through to make "glassware", it is
> > inconceivable that you could do that as a "home brew" project. And this
> > was the same HP facility that already made the 5065 rubidium standard.
> > The best you could hope to do is to start with a commercial "physics
> > package" as we called it, and make your own electronics for it. Reading
> > books about how rubidium standards work, etc is fine, but again, you
> > can't home brew the glassware.
> >
> > ---
> > Rick Karlquist
> > N6RK
> >
> > On 2023-06-06 15:39, Tom Van Baak via time-nuts wrote:
> >
> >> Hi Leo,
> >>
> >> That sounds like a fun project. Here are some extremely informative
> resources:
> >>
> >> "Introduction to the Rubidium Frequency Standard"
> >> by Michael Parker, 358 pages
> >> http://www.leapsecond.com/u/parker/ParkerIntroRFS-PPCP.pdf
> >>
> >> "Rubidium Frequency Standard Primer"
> >> by Bill Riley, 163 pages
> >>
> http://www.wriley.com/Rubidium%20Frequency%20Standard%20Primer%20102211.pdf
> >>
> >> "Selection Criteria for Rubidium Frequency Standards"
> >> by Bill Riley, 51 pages
> >>
> http://www.wriley.com/Selection%20Criteria%20for%20Rubidium%20Frequency%20Standards.pdf
> >>
> >> Also read service manuals for commercial Rb products. Didier's site has
> a nice collection. Search by product number (e.g., 5065a) or by title
> (e.g., rubidium):
> >>
> >> http://www.ko4bb.com/getsimple/index.php?id=manuals
> >>
> >> /tvb
> >>
> >> On 6/6/2023 12:25 PM, Leo Ahluwalia via time-nuts wrote:
> >>
> >>> Hello, my name is Leo, and I was wondering about the feasibility of
> >>> creating a simple rubidium atomic clock at home, and good places to
> source
> >>> parts for this sort of project. I was also wondering what instruments
> and
> >>> specialized knowledge would be required depending on how pre-built the
> >>> parts are, for example, the prerequisite knowledge for creating PLL(s)
> for
> >>> both frequency division to provide an output and also to modulate the
> input
> >>> of the microwave oscillator. Any good resources or PDFs would be
> greatly
> >>> appreciated, as I am very new to frequency analysis and phase
> manipulation
> >>> in general. I was also hoping to keep the cost of the project soft-line
> >>> below 500$, though that would be assuming a decent level of precision
> and
> >>> already possessing basic equipment (oscilloscope, multimeter, etc...).
> Safety
> >>> is also a major concern, as I know while the intensity of the EM waves
> >>> involved is low, the power source may or may not be. This is all of
> course
> >>> assuming a basic design, where my assumption is that it will involve
> the
> >>> microwaves being shot at a rubidium vapor cell which is directed
> towards a
> >>> photodetector. This would then be connected up to the PLL and
> circuitry to
> >>> both provide a stable standard while also modulating the microwave
> >>> oscillator to offset any external environmental factors. I don't have a
> >>> clear vision of what would truly be the best design for both
> simplicity and
> >>> cost, though this is what I've found to be a common design in what I've
> >>> looked at online.
> >>>
> >>> Thanks, Leo
> >> _______________________________________________
> >> time-nuts mailing list -- time-nuts@lists.febo.com
> >> To unsubscribe send an email to time-nuts-leave@lists.febo.com
> > _______________________________________________
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe send an email to time-nuts-leave@lists.febo.com
> _______________________________________________
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe send an email to time-nuts-leave@lists.febo.com
>
_______________________________________________
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
BS
Bob Stewart
Thu, Jun 15, 2023 1:06 AM
Hi Adrian,
My link didn't come through the last time, so let's try this differently.
Re the Rb capsules, take a look at this ebay listing. Is this what you were thinking of? Just enter this number in the search field on ebay: 124012486501
Bob
On Wednesday, June 7, 2023 at 01:14:43 PM CDT, Adrian Godwin via time-nuts <time-nuts@lists.febo.com> wrote:
I have seen glass rubidium capsules on ebay a couple of years ago. None at
the moment and they were possibly in Russia. They were just a glass capsule
- no surrounding components, not even a coil, but they weren't particularly
expensive,. Certainly not HP-spares expensive.
Is such a thing useful (to provide 'the hardest thing') for Leo's project
if they reappear ?
On Wed, Jun 7, 2023 at 1:26 PM Magnus Danielson via time-nuts <
time-nuts@lists.febo.com> wrote:
Hi,
I agree with Rick and was about to make more or less the same comment.
The glas package is the hardest thing to do, and there is also a certain
magic to mix the buffer gas just the right way to frequency compensate
the wall shift. Already there comes the aspect of knowing what wallshift
you will get, so you need reasonable reproduceability in both the glass
and pressure and mix in gases. To put that in other words, I am not THAT
crazy, yet.
Next level is the cavity you put the glas-ware into. The Q of that
resonator is not irrelevant, so you want to handle that.
There is a certain magic to the temperatures of the rubidium lamp and
that of the rubidium filter. This has consequences on how the physical
package is built. Some of this can be avoided today by using diodeds,
and that may even open up for avoiding the tuned resonator, but brings
in it's own set of issues.
Achievable engineering challenges, but maybe hard to do as a hobbyist.
The remaining temperature controls, FLL-lock of oscillator, synthesis
have become more and more achieveable over the years. That has become
hobbyist achieveable for sure.
However, just attempting to study up on a subject like this forces you
to learn alot, so even if you do not do a single soldering, you can have
improved your knowledge.
I would consider recycle an existing physical package that works and
make modern electronics for it. That should be plenty of challenges and
quite achieveable.
Cheers,
Magnus
On 2023-06-07 02:26, Richard Karlquist via time-nuts wrote:
In a former life, I was on the design team of a mini rubidium standard
at Hewlett-Packard. We built some working prototypes before it was
cancelled. It was going to have the model number 10816. I was the RF
person, but I worked very closely with the other team members.
Remembering what we had to go through to make "glassware", it is
inconceivable that you could do that as a "home brew" project. And this
was the same HP facility that already made the 5065 rubidium standard.
The best you could hope to do is to start with a commercial "physics
package" as we called it, and make your own electronics for it. Reading
books about how rubidium standards work, etc is fine, but again, you
can't home brew the glassware.
Rick Karlquist
N6RK
On 2023-06-06 15:39, Tom Van Baak via time-nuts wrote:
Hi Leo,
That sounds like a fun project. Here are some extremely informative
"Selection Criteria for Rubidium Frequency Standards"
by Bill Riley, 51 pages
Also read service manuals for commercial Rb products. Didier's site has
a nice collection. Search by product number (e.g., 5065a) or by title
(e.g., rubidium):
Hello, my name is Leo, and I was wondering about the feasibility of
creating a simple rubidium atomic clock at home, and good places to
parts for this sort of project. I was also wondering what instruments
specialized knowledge would be required depending on how pre-built the
parts are, for example, the prerequisite knowledge for creating PLL(s)
both frequency division to provide an output and also to modulate the
of the microwave oscillator. Any good resources or PDFs would be
appreciated, as I am very new to frequency analysis and phase
in general. I was also hoping to keep the cost of the project soft-line
below 500$, though that would be assuming a decent level of precision
already possessing basic equipment (oscilloscope, multimeter, etc...).
is also a major concern, as I know while the intensity of the EM waves
involved is low, the power source may or may not be. This is all of
assuming a basic design, where my assumption is that it will involve
microwaves being shot at a rubidium vapor cell which is directed
photodetector. This would then be connected up to the PLL and
both provide a stable standard while also modulating the microwave
oscillator to offset any external environmental factors. I don't have a
clear vision of what would truly be the best design for both
cost, though this is what I've found to be a common design in what I've
looked at online.
Thanks, Leo
Hi Adrian,
My link didn't come through the last time, so let's try this differently.
Re the Rb capsules, take a look at this ebay listing. Is this what you were thinking of? Just enter this number in the search field on ebay: 124012486501
Bob
On Wednesday, June 7, 2023 at 01:14:43 PM CDT, Adrian Godwin via time-nuts <time-nuts@lists.febo.com> wrote:
I have seen glass rubidium capsules on ebay a couple of years ago. None at
the moment and they were possibly in Russia. They were just a glass capsule
- no surrounding components, not even a coil, but they weren't particularly
expensive,. Certainly not HP-spares expensive.
Is such a thing useful (to provide 'the hardest thing') for Leo's project
if they reappear ?
On Wed, Jun 7, 2023 at 1:26 PM Magnus Danielson via time-nuts <
time-nuts@lists.febo.com> wrote:
> Hi,
>
> I agree with Rick and was about to make more or less the same comment.
>
> The glas package is the hardest thing to do, and there is also a certain
> magic to mix the buffer gas just the right way to frequency compensate
> the wall shift. Already there comes the aspect of knowing what wallshift
> you will get, so you need reasonable reproduceability in both the glass
> and pressure and mix in gases. To put that in other words, I am not THAT
> crazy, yet.
>
> Next level is the cavity you put the glas-ware into. The Q of that
> resonator is not irrelevant, so you want to handle that.
>
> There is a certain magic to the temperatures of the rubidium lamp and
> that of the rubidium filter. This has consequences on how the physical
> package is built. Some of this can be avoided today by using diodeds,
> and that may even open up for avoiding the tuned resonator, but brings
> in it's own set of issues.
>
> Achievable engineering challenges, but maybe hard to do as a hobbyist.
> The remaining temperature controls, FLL-lock of oscillator, synthesis
> have become more and more achieveable over the years. That has become
> hobbyist achieveable for sure.
>
> However, just *attempting* to study up on a subject like this forces you
> to learn alot, so even if you do not do a single soldering, you can have
> improved your knowledge.
>
> I would consider recycle an existing physical package that works and
> make modern electronics for it. That should be plenty of challenges and
> quite achieveable.
>
> Cheers,
> Magnus
>
> On 2023-06-07 02:26, Richard Karlquist via time-nuts wrote:
> > In a former life, I was on the design team of a mini rubidium standard
> > at Hewlett-Packard. We built some working prototypes before it was
> > cancelled. It was going to have the model number 10816. I was the RF
> > person, but I worked very closely with the other team members.
> > Remembering what we had to go through to make "glassware", it is
> > inconceivable that you could do that as a "home brew" project. And this
> > was the same HP facility that already made the 5065 rubidium standard.
> > The best you could hope to do is to start with a commercial "physics
> > package" as we called it, and make your own electronics for it. Reading
> > books about how rubidium standards work, etc is fine, but again, you
> > can't home brew the glassware.
> >
> > ---
> > Rick Karlquist
> > N6RK
> >
> > On 2023-06-06 15:39, Tom Van Baak via time-nuts wrote:
> >
> >> Hi Leo,
> >>
> >> That sounds like a fun project. Here are some extremely informative
> resources:
> >>
> >> "Introduction to the Rubidium Frequency Standard"
> >> by Michael Parker, 358 pages
> >> http://www.leapsecond.com/u/parker/ParkerIntroRFS-PPCP.pdf
> >>
> >> "Rubidium Frequency Standard Primer"
> >> by Bill Riley, 163 pages
> >>
> http://www.wriley.com/Rubidium%20Frequency%20Standard%20Primer%20102211.pdf
> >>
> >> "Selection Criteria for Rubidium Frequency Standards"
> >> by Bill Riley, 51 pages
> >>
> http://www.wriley.com/Selection%20Criteria%20for%20Rubidium%20Frequency%20Standards.pdf
> >>
> >> Also read service manuals for commercial Rb products. Didier's site has
> a nice collection. Search by product number (e.g., 5065a) or by title
> (e.g., rubidium):
> >>
> >> http://www.ko4bb.com/getsimple/index.php?id=manuals
> >>
> >> /tvb
> >>
> >> On 6/6/2023 12:25 PM, Leo Ahluwalia via time-nuts wrote:
> >>
> >>> Hello, my name is Leo, and I was wondering about the feasibility of
> >>> creating a simple rubidium atomic clock at home, and good places to
> source
> >>> parts for this sort of project. I was also wondering what instruments
> and
> >>> specialized knowledge would be required depending on how pre-built the
> >>> parts are, for example, the prerequisite knowledge for creating PLL(s)
> for
> >>> both frequency division to provide an output and also to modulate the
> input
> >>> of the microwave oscillator. Any good resources or PDFs would be
> greatly
> >>> appreciated, as I am very new to frequency analysis and phase
> manipulation
> >>> in general. I was also hoping to keep the cost of the project soft-line
> >>> below 500$, though that would be assuming a decent level of precision
> and
> >>> already possessing basic equipment (oscilloscope, multimeter, etc...).
> Safety
> >>> is also a major concern, as I know while the intensity of the EM waves
> >>> involved is low, the power source may or may not be. This is all of
> course
> >>> assuming a basic design, where my assumption is that it will involve
> the
> >>> microwaves being shot at a rubidium vapor cell which is directed
> towards a
> >>> photodetector. This would then be connected up to the PLL and
> circuitry to
> >>> both provide a stable standard while also modulating the microwave
> >>> oscillator to offset any external environmental factors. I don't have a
> >>> clear vision of what would truly be the best design for both
> simplicity and
> >>> cost, though this is what I've found to be a common design in what I've
> >>> looked at online.
> >>>
> >>> Thanks, Leo
> >> _______________________________________________
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