[time-nuts] Better quartz crystals with single isotope ?

Discussion:

Poul-Henning Kamp

2018-04-22 16:19:39 UTC

Silicon comes in a number of isotopes but 95% of it is Silicon-28.

When you make pure mono-crystaline silicon, you get 50-60% better
thermal conductivity if you only use Silicon-28 atoms.

Yes, you read that right: 50-60% improvement for removing the
remaining 5% other silicon isotopes, and for this and other reasons,
sorting silicon atoms by isotope is now a thing, which amongst other
side effects have made the Advogardo Project possible.

I can't help wonder if there may be similar interesting effects in
quartz crystals, if they were monoisotopic ?

Several relevant mechanisms can be imagined, lower internal damping,
higher stiffness etc. etc.

We know a LOT about quartz and have a very good theory for its
behaviours, but i find no signs anybody has ever touched monoisotopic
Quartz.

The obvious experiment is not rocket-science, nor does it demand
inordinate resources for amateurs, see for instance from 03:35:

https://archive.org/details/59554KrystallosCF

But it is clearly beyond what I have time to persue.

Do we know anybody in the quartz business who needs a really cool
research project ?

Poul-Henning

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Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
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Never attribute to malice what can adequately be explained by incompetence.
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Bob kb8tq

2018-04-22 17:20:23 UTC

Permalink

Post by Poul-Henning Kamp
Silicon comes in a number of isotopes but 95% of it is Silicon-28.
When you make pure mono-crystaline silicon, you get 50-60% better
thermal conductivity if you only use Silicon-28 atoms.
Yes, you read that right: 50-60% improvement for removing the
remaining 5% other silicon isotopes, and for this and other reasons,
sorting silicon atoms by isotope is now a thing, which amongst other
side effects have made the Advogardo Project possible.
I can't help wonder if there may be similar interesting effects in
quartz crystals, if they were monoisotopic ?
Several relevant mechanisms can be imagined, lower internal damping,
higher stiffness etc. etc.
We know a LOT about quartz and have a very good theory for its
behaviours, but i find no signs anybody has ever touched monoisotopic
Quartz.
The obvious experiment is not rocket-science, nor does it demand
https://archive.org/details/59554KrystallosCF
But it is clearly beyond what I have time to persue.
Do we know anybody in the quartz business who needs a really cool
research project ?

You could put it on the list with the 1 Kg quartz resonator proposal …..

https://tf.nist.gov/general/pdf/2638.pdf <https://tf.nist.gov/general/pdf/2638.pdf>

Also an offshoot of people thinking about the implications of all this as it relates to resonators.

Bob

Post by Poul-Henning Kamp
Poul-Henning
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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Richard (Rick) Karlquist

2018-04-22 20:48:28 UTC

Permalink

A neophyte question about this topic: Since we know that 0.001
cubic meter of water displaces 1 liter, and that it weighs 1 kg,
and meters are based on wavelengths of light, why
do we need a separate artifact of mass? Also, can we measure
the mass of the artifact in Paris based on water substitution?

Articles about this topic are always presented as if the answers
are obvious.

Don't they base 0 degree Celsius on the triple point of water?
What's wrong with that?

Rick

Post by Bob kb8tq
Hi

You could put it on the list with the 1 Kg quartz resonator proposal …..
https://tf.nist.gov/general/pdf/2638.pdf <https://tf.nist.gov/general/pdf/2638.pdf>
Also an offshoot of people thinking about the implications of all this as it relates to resonators.
Bob

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Richard (Rick) Karlquist

2018-04-22 21:11:04 UTC

Permalink

Post by Bob kb8tq

Post by Poul-Henning Kamp
Do we know anybody in the quartz business who needs a really cool
research project ?

You could put it on the list with the 1 Kg quartz resonator proposal …..
https://tf.nist.gov/general/pdf/2638.pdf <https://tf.nist.gov/general/pdf/2638.pdf>
Also an offshoot of people thinking about the implications of all this as it relates to resonators.
Bob

The cited article "must be true" because of its authors, I guess, but it
makes no sense to me. They seem to be assuming that the resonant
frequency is inversely proportional to mass? We all know three things:

1. Frequency is inversely proportional to thickness. Not mass.

2. Frequency aging is affected by stress relaxation in well built
resonators. The old idea that mass is gradually evaporating from
the resonator to the enclosure (glass enclosures) or mass is gradually
evaporating from the enclosure (metal enclosures) to depositing
on the resonator is simply obsolete in terms of current technology.
Thus again frequency is not a proxy for mass.

3. Resonators can "jump" in frequency without jumping in mass.

Given these facts, I am lost as how this is supposed to work.
Surely, the authors are well aware of the 3 items above.

Also, why does the resonator have to be a whole kilogram anyway.
If it weighed exactly 10 grams, couldn't you still compare it
to a kilogram using 100:1 leverage?

Can anyone straighten me out?

Rick
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Bill Hawkins

2018-04-23 04:21:45 UTC

Permalink

Good questions.

The one that bothers me is the magnetic levitation required to compare
the standard to anything. You can't put other materials inside the
vacuum bell with the standard. I looked up the paper, but it's behind a
$40 pay-wall.

Electromagnets will levitate permanent magnets, but the effect is not
stable, with the free magnet sliding out of the field.
Diamagnetic materials will be stable, but the effect is so weak it would
require superconducting electromagnets. Quartz, as it happens, is
diamagnetic.

Now the problem is to apply identical levitation to dissimilar
materials. This would seem to require identical superconducting magnets
and identical levitated platforms. Identical currents can flow in the
levitating magnets simply by connecting them in series. In order for the
platforms to be identically levitated, they have to be an identical
distance from the levitating magnet. Measuring that to the required
precision could be a challenge.

Machining physical parts can be done to 10 E-6. That's not enough, so
the mechanism will require calibration. I suppose they could compare it
to the present platinum standard. Then there's the question of
calibration interval, and what to use as the standard. Counting
oscillations of atoms would be so much easier.

I think Rick's three points make this a non-starter. It's a case of
experts in metrology not having enough expertise in quarts resonators.

In answer to why they can't use 10 grams, the comparison has to be 100
times more accurate than that for 1000 grams.

Hope I haven't strayed too far off topic, and wasted my time.

Bill Hawkins

-----Original Message-----
From: time-nuts [mailto:time-nuts-***@febo.com] On Behalf Of Richard
(Rick) Karlquist
Sent: Sunday, April 22, 2018 4:11 PM
To: Discussion of precise time and frequency measurement; Bob kb8tq
Subject: Re: [time-nuts] Better quartz crystals with single isotope ?

Post by Bob kb8tq

Post by Poul-Henning Kamp
Do we know anybody in the quartz business who needs a really cool
research project ?

You could put it on the list with the 1 Kg quartz resonator proposal

...

Post by Bob kb8tq
https://tf.nist.gov/general/pdf/2638.pdf
<https://tf.nist.gov/general/pdf/2638.pdf>
Also an offshoot of people thinking about the implications of all this

as it relates to resonators.

Post by Bob kb8tq
Bob

The cited article "must be true" because of its authors, I guess, but it
makes no sense to me. They seem to be assuming that the resonant
frequency is inversely proportional to mass? We all know three things:

1. Frequency is inversely proportional to thickness. Not mass.

2. Frequency aging is affected by stress relaxation in well built
resonators. The old idea that mass is gradually evaporating from the
resonator to the enclosure (glass enclosures) or mass is gradually
evaporating from the enclosure (metal enclosures) to depositing on the
resonator is simply obsolete in terms of current technology.
Thus again frequency is not a proxy for mass.

3. Resonators can "jump" in frequency without jumping in mass.

Given these facts, I am lost as how this is supposed to work.
Surely, the authors are well aware of the 3 items above.

Also, why does the resonator have to be a whole kilogram anyway.
If it weighed exactly 10 grams, couldn't you still compare it to a
kilogram using 100:1 leverage?

Can anyone straighten me out?

Rick
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Bob kb8tq

2018-04-23 13:49:36 UTC

Permalink

Post by Bill Hawkins
Good questions.
The one that bothers me is the magnetic levitation required to compare
the standard to anything. You can't put other materials inside the
vacuum bell with the standard. I looked up the paper, but it's behind a
$40 pay-wall.
Electromagnets will levitate permanent magnets, but the effect is not
stable, with the free magnet sliding out of the field.
Diamagnetic materials will be stable, but the effect is so weak it would
require superconducting electromagnets. Quartz, as it happens, is
diamagnetic.
Now the problem is to apply identical levitation to dissimilar
materials. This would seem to require identical superconducting magnets
and identical levitated platforms. Identical currents can flow in the
levitating magnets simply by connecting them in series. In order for the
platforms to be identically levitated, they have to be an identical
distance from the levitating magnet. Measuring that to the required
precision could be a challenge.
Machining physical parts can be done to 10 E-6. That's not enough, so
the mechanism will require calibration. I suppose they could compare it
to the present platinum standard. Then there's the question of
calibration interval, and what to use as the standard. Counting
oscillations of atoms would be so much easier.
I think Rick's three points make this a non-starter. It's a case of
experts in metrology not having enough expertise in quarts resonators.

Just for the record John Vig knows quite a bit about quartz resonators ….

Bob

Post by Bill Hawkins
In answer to why they can't use 10 grams, the comparison has to be 100
times more accurate than that for 1000 grams.
Hope I haven't strayed too far off topic, and wasted my time.
Bill Hawkins
-----Original Message-----
(Rick) Karlquist
Sent: Sunday, April 22, 2018 4:11 PM
To: Discussion of precise time and frequency measurement; Bob kb8tq
Subject: Re: [time-nuts] Better quartz crystals with single isotope ?

Post by Bob kb8tq

Post by Poul-Henning Kamp
Do we know anybody in the quartz business who needs a really cool
research project ?

You could put it on the list with the 1 Kg quartz resonator proposal

...

Post by Bob kb8tq
https://tf.nist.gov/general/pdf/2638.pdf
<https://tf.nist.gov/general/pdf/2638.pdf>
Also an offshoot of people thinking about the implications of all this

as it relates to resonators.

Post by Bob kb8tq
Bob

The cited article "must be true" because of its authors, I guess, but it
makes no sense to me. They seem to be assuming that the resonant
1. Frequency is inversely proportional to thickness. Not mass.
2. Frequency aging is affected by stress relaxation in well built
resonators. The old idea that mass is gradually evaporating from the
resonator to the enclosure (glass enclosures) or mass is gradually
evaporating from the enclosure (metal enclosures) to depositing on the
resonator is simply obsolete in terms of current technology.
Thus again frequency is not a proxy for mass.
3. Resonators can "jump" in frequency without jumping in mass.
Given these facts, I am lost as how this is supposed to work.
Surely, the authors are well aware of the 3 items above.
Also, why does the resonator have to be a whole kilogram anyway.
If it weighed exactly 10 grams, couldn't you still compare it to a
kilogram using 100:1 leverage?
Can anyone straighten me out?
Rick
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djl

2018-04-22 17:21:38 UTC

Permalink

Interesting indeed! Seems as if there ought to be info about drawing
crystals mono vs poly isotopic somewhere out there. Also some info about
crystal grain boundaries that might be generated in a zone furnace
drawing by isotope inclusions. Seems the boundaries are responsible for
the sudden frequency shifts? My solid state physics is evanescent, but
there ought to be a TN with some info...
Don

--
Dr. Don Latham
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304

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djl

2018-04-22 17:34:30 UTC

Permalink

Darn. maybe not grain boundaries, but dislocations? or both?
Don

jimlux

2018-04-22 17:46:05 UTC

Permalink

A note the cigarette in the guy's hand - trace contaminants probably
increase the yield <grin>

I've looked into "garage manufacture" of crystals, although I was
looking more at Cr and Ti doped alumina. The movie looks like it's using
the "solution" approach (which has also been used to grow synthetic
emeralds) which is similar to how it happens in nature. These days, I
wonder whether continuous pulling from a melt like silicon boules might
not be a better strategy.

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Bob kb8tq

2018-04-22 20:46:14 UTC

Permalink

If you are after a quartz crystal, pulling is not an option. You grow them from solution under high pressure
and moderate temperature.

Bob

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Mark Sims

2018-04-22 18:37:44 UTC

Permalink

Single isotope diamond is 50% better thermal conductivity of normal diamond. It has been used in laser optics and thermal transfer applications (semiconductor heatsinks). I think the highest reported thermal transfer rate used isotopically pure diamond etched with micro-fluidic channels fed with coolant. GE makes the diamond material... it was developed as part of Reagan's Star Wars project.

Isotopically pure silicon has 60% better thermal conductivity than natural silicon.

Isotopically pure platinum has been used in RTD temperature sensors.
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Brooke Clarke

2018-04-22 21:29:22 UTC

Permalink

Hi:

Isotopes of an element differ in the number of neutrons. The chemical reactions of an element are governed by the
electrons, which are the same for all isotopes, so chemical means can not be used to separate the isotopes.
There are a number of ways of making the separation, for Uranium see:
https://en.wikipedia.org/wiki/Clinton_Engineer_Works#Facilities

It's not clear to me how the isotopes of water are accounted for in it's physical properties. Have these been refined
and defined for each isotope? This may be important since the properties of water show up a lot as the basis for other
definitions.
https://en.wikipedia.org/wiki/Isotopes_of_hydrogen
https://en.wikipedia.org/wiki/Isotopes_of_oxygen

PS One of the names of the company I worked for was FEI Microwave. There was a rumor that the funder of that company had
a bunch of very special quartz in the vault and that crystals cut from that material had better phase noise than off the
shelf crystals hence he had an advantage over other vendors.
http://prc68.com/I/Aertech.shtml#Names
--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

-------- Original Message --------

Post by Mark Sims
Single isotope diamond is 50% better thermal conductivity of normal diamond. It has been used in laser optics and thermal transfer applications (semiconductor heatsinks). I think the highest reported thermal transfer rate used isotopically pure diamond etched with micro-fluidic channels fed with coolant. GE makes the diamond material... it was developed as part of Reagan's Star Wars project.
Isotopically pure silicon has 60% better thermal conductivity than natural silicon.
Isotopically pure platinum has been used in RTD temperature sensors.
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Brooke Clarke

2018-04-22 22:28:10 UTC

Permalink

Hi:

I found a perfect quartz ball. It took Stanford many decades to make it.
https://einstein.stanford.edu/TECH/technology1.html
--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

-------- Original Message --------

Post by Brooke Clarke
Isotopes of an element differ in the number of neutrons. The chemical reactions of an element are governed by the
electrons, which are the same for all isotopes, so chemical means can not be used to separate the isotopes.
https://en.wikipedia.org/wiki/Clinton_Engineer_Works#Facilities
It's not clear to me how the isotopes of water are accounted for in it's physical properties. Have these been refined
and defined for each isotope? This may be important since the properties of water show up a lot as the basis for
other definitions.
https://en.wikipedia.org/wiki/Isotopes_of_hydrogen
https://en.wikipedia.org/wiki/Isotopes_of_oxygen
PS One of the names of the company I worked for was FEI Microwave. There was a rumor that the funder of that company
had a bunch of very special quartz in the vault and that crystals cut from that material had better phase noise than
off the shelf crystals hence he had an advantage over other vendors.
http://prc68.com/I/Aertech.shtml#Names

Bob kb8tq

2018-04-22 23:56:50 UTC

Permalink

Hi

Quartz ball yes. It’s a fused quartz (as opposed to crystalline quartz) ball …..
Fused quartz is a lot easier to work with. In order to be piezoelectric, it must
be crystalline. The piezo properties are what lets you make a resonator out of it.

Bob

I found a perfect quartz ball. It took Stanford many decades to make it.
https://einstein.stanford.edu/TECH/technology1.html
--
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
-------- Original Message --------

Isotopes of an element differ in the number of neutrons. The chemical reactions of an element are governed by the electrons, which are the same for all isotopes, so chemical means can not be used to separate the isotopes.
https://en.wikipedia.org/wiki/Clinton_Engineer_Works#Facilities
It's not clear to me how the isotopes of water are accounted for in it's physical properties. Have these been refined and defined for each isotope? This may be important since the properties of water show up a lot as the basis for other definitions.
https://en.wikipedia.org/wiki/Isotopes_of_hydrogen
https://en.wikipedia.org/wiki/Isotopes_of_oxygen
PS One of the names of the company I worked for was FEI Microwave. There was a rumor that the funder of that company had a bunch of very special quartz in the vault and that crystals cut from that material had better phase noise than off the shelf crystals hence he had an advantage over other vendors.
http://prc68.com/I/Aertech.shtml#Names

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Bob kb8tq

2018-04-22 22:55:02 UTC

Permalink

Hi

If you get into “temperature nuts” territory, the triple point of water varies with the isotope
“mix” in the standard. The “correct” mix turns out to be “mid continent deep well water”.

If you make a resonator that is very thick, you also need to make it very wide. If you don’t,
the width to thickness ratio gets into things. You start having “modes” that couple and that
messes things up. Since we are already into the area that this matters on a 5 MHz 3rd in
modern packages ….. you make it thicker and you increase the mass.

As you drop the frequency of a resonator, the acoustic loss goes down. To the degree that
limits your resonator Q ( back to things like thickness to diameter) the Q would be much higher
on a (say) 500 KHz SC than it is on a 5 MHz device. Q goes up and ADEV improves. Yes, that
assumes that temperature fluctuations (or something weird) don’t get in the way.

How you get an single isotope / zero contaminant quartz crystal - not at all clear. You have both
silicon and oxygen involved. You have to grow the crystal in some sort of solution. You also
have to ultimately start from a natural quartz seed ( you may be generations removed from it,
but that’s still the starting point),

Just for reference, your 5 MHz third is about a half inch in diameter. A 5 MHz 5th would be a bit
larger in diameter to work well. Scale the third to 500 KHz and you are at 5” in diameter.
Does it weigh 1 Kg yet? It would have to be a bit over an inch thick for that to be true. That’s about
10X to thick…… By the time you get to 200 KHz things are well over the target. Somewhere in the
250 to 400 KHz range (depending on a lot of things) would likely be the net result.

Bob

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Martin VE3OAT

2018-04-23 20:37:24 UTC

Permalink

I always thought crystals with dislocations were used to mark the band
edge frequencies.
... Martin VE3OAT

- - - - - - - - - - - - - - - - - -

Post by djl
Darn. maybe not grain boundaries, but dislocations? or both?
Don

- - - - - - - - - - - - - - - - - - -

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Donald E. Pauly

2018-11-16 15:22:37 UTC

Permalink

This effect is real, as this Russian paper shows,
https://www.sciencedirect.com/science/article/pii/S0038109803003673 .

Natural carbon diamond conducts heat five times better than copper whereas
natural silicon conducts heat three times worse. Isotopically
pure carbon makes 50% better thermal conductivity,
https://en.wikipedia.org/wiki/Isotopically_pure_diamond. Also
silicon isotopes are:

silicon 28 92.2%
silicon 29 4.7%
silicon 30 3.1%
https://en.wikipedia.org/wiki/Silicon.

Mono-isotope silicon has been investigated in order to make possible the
exact determination of Avogadro's number, ~6.02x10^26
atoms/mole=protons/kilogram. It can then be grown in a precise diameter
sphere. See
https://www.nist.gov/si-redefinition/kilogram-silicon-
spheres-and-international-avogadro-project
. The Kibble balance just recently won out over the Avogadro project
because it is more repeatable and accurate.

BTW, quartz is silicon oxide, which is a totally different beast than pure
silicon. Even if the quartz is mono-isotopic the oxygen would have to be
as well. Oxygen is also present in three isotopes:

O-16 99.76%
O-17 0.04%
O-18 0.20%
https://en.wikipedia.org/wiki/Oxygen

I doubt that crystal improvements are possible with quartz made with atoms
that are mono-isotope. Mechanical properties depend upon electron shell
attractions and the number of neutrons in the nucleus have little to do
with it. Quartz molecules are five times heavier than carbon atoms.
Isotopic effects must also be much less. Growing pure quartz crystals is
more important that worrying about isotopes. Any impurities disrupt the
structure and cause dislocations. This reduces Q by increasing ESR.
Quartz has an intrinsic Q of 16x10^6 divided by the frequency in
megacycles. I don't know the source of that limitation but I doubt that it
is thermal conductivity.

Even then this would be a multi million dollar project. What good would
slightly better thermal conductivity do if the crystal blank is all at the
same temperature to begin with? I cannot find anything on Q effects from
single isotope quartz. Even an improvement of 50% in Q is hardly worth
raising the price of quartz by 1,000:1 to make it mono-isotope. Money is
likely much better spent on ways to grow
quartz better and faster.

There has been a little work done on levitating crystal blanks by high
voltage RF fields so that no loss or instability is present in lead
attachments. I have done a lot of calculations on that subject. I talked
to Bliley about it some 15 years ago. Less than a Watt was sufficient to
levitate a crystal by a few microns in a 100 g vibration environment.
Something like 30 pFd of series capacitance would be present on each face
of the blank.

WB0KVV

incompetence.

Post by Poul-Henning Kamp
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