Testing replacement lamps for HP5065A
Here are details on some tests I ran on replacement lamps for the
HP5065A.
Cheers!
Corby
Hi Corby:
I got a tour of Stanford Research by the owner over a couple of decades ago. He is a physicist and they hire physicists
rather than engineers.
He said the lamp in the PRS10 is designed to last a very long time and the Rb lamps used in other standards did not last
that long.
https://prc68.com/I/PRS10.shtml
--
Have Fun,
Brooke Clarke
https://www.PRC68.com
axioms:
- The extent to which you can fix or improve something will be limited by how well you understand how it works.
- Everybody, with no exceptions, holds false beliefs.
-------- Original Message --------
Here are details on some tests I ran on replacement lamps for the
HP5065A.
Cheers!
Corby
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
Hi Corby,
It seems that all the lamps tested are from used rubidium standards.
Is it possible to buy "off the shelf" rubidium lamps somewhere?
Or is it so "specialized" that's only way to obtain them?
Thank you.
Best regards
On Thu, Sep 15, 2022 at 10:53 PM Corby Dawson via time-nuts
time-nuts@lists.febo.com wrote:
Here are details on some tests I ran on replacement lamps for the
HP5065A.
Cheers!
Corby_______________________________________________
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
--
/* Lin Ke-Fong
- anotherlin@gmail.com
- I always do what I say, especially if it's something stupid.
*/
Hi
You can get what might be Rb lamps on eBay. Since the
contents of the glass bulb are a mix of things, you never really
know if what’s in there is a good mix. The inside of some of the
bulbs is coated with Teflon ( this is a good thing ). Again, you
never quite know if this or that auction item is coated or not.
Next up, you need the right amount of Rb in the lamp. To little and
there’s not enough atoms to do the job.
Since the bulbs get used for various things other than standards,
you could easily get some that aren’t going to be any fun to use
in a standard.
Bob
On Sep 16, 2022, at 2:59 PM, Ke-Fong Lin via time-nuts time-nuts@lists.febo.com wrote:
Hi Corby,
It seems that all the lamps tested are from used rubidium standards.
Is it possible to buy "off the shelf" rubidium lamps somewhere?
Or is it so "specialized" that's only way to obtain them?
Thank you.
Best regards
On Thu, Sep 15, 2022 at 10:53 PM Corby Dawson via time-nuts
time-nuts@lists.febo.com wrote:
Here are details on some tests I ran on replacement lamps for the
HP5065A.
Cheers!
Corby_______________________________________________
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
--
/* Lin Ke-Fong
- anotherlin@gmail.com
- I always do what I say, especially if it's something stupid.
*/
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
As a bit of background - When I was an undergraduate, I worked with a
group using optically pumped 87Rb to orient hydrogen via spin exchange to
measure the hydrogen hyperfine frequency. At that time, our Rb lamps were
RF excited 1 cm dia spherical bulbs. There was a bit of black magic in
the choice and type of noble gas used to maintain the discharge. Rb vapor
pressure was controlled by bulb temperature. I don't believe there was
any teflon coating in the lamps; teflon coating was used, however, in the
optical pumping cell to reduce collisional disorientation and consequent
broadening. At that time we used circular polarizers to achieve the
pumping effect. I note that the SRS Rb standard uses intensity pumping,
which I consider cruder.
I note that Laser diodes in the correct wavelength range are available
for under $20.00 (Rohm RLD78NZM5 and similar) from Digikey and Mouser.
These have 10 mW optical single mode output. Most laser diodes are easily
tuned over a small range; the well defined beam and its polarization
characteristics could provide a significant advantage over a gas
discharge lamp. Intensity stabilization would probably be necessary to
achieve the low noise level necessary for optical pumping. These laser
diodes include an integrated photodetector to facilitate stabilization.
Anyway, it might be worth looking into them as lamp replacements.
Stephen Menasian
On Fri, 16 Sep 2022 22:59:22 +0200
Ke-Fong Lin via time-nuts time-nuts@lists.febo.com wrote:
Hi Corby,
It seems that all the lamps tested are from used rubidium standards.
Is it possible to buy "off the shelf" rubidium lamps somewhere?
Or is it so "specialized" that's only way to obtain them?
Thank you.
Best regards
On Thu, Sep 15, 2022 at 10:53 PM Corby Dawson via time-nuts
time-nuts@lists.febo.com wrote:
Here are details on some tests I ran on replacement lamps for the
HP5065A.Cheers!
Corby_______________________________________________
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
--
/* Lin Ke-Fong
- anotherlin@gmail.com
- I always do what I say, especially if it's something stupid.
*/
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
Seems like a really specialized science. Ironically everything is
shrinking. We can understand why but the larger bulb Rb seem to last
longer. Perhaps it's a sign of the times. Smaller and more disposable.
Sadly that probably means throw away standards. Perhaps we'll live to see
newer technology like room temperature ion traps for quantum clocks.
Bill
On Sat, Sep 17, 2022, 4:17 PM Bob kb8tq via time-nuts <
time-nuts@lists.febo.com> wrote:
Hi
You can get what might be Rb lamps on eBay. Since the
contents of the glass bulb are a mix of things, you never really
know if what’s in there is a good mix. The inside of some of the
bulbs is coated with Teflon ( this is a good thing ). Again, you
never quite know if this or that auction item is coated or not.
Next up, you need the right amount of Rb in the lamp. To little and
there’s not enough atoms to do the job.
Since the bulbs get used for various things other than standards,
you could easily get some that aren’t going to be any fun to use
in a standard.
Bob
On Sep 16, 2022, at 2:59 PM, Ke-Fong Lin via time-nuts <
time-nuts@lists.febo.com> wrote:
Hi Corby,
It seems that all the lamps tested are from used rubidium standards.
Is it possible to buy "off the shelf" rubidium lamps somewhere?
Or is it so "specialized" that's only way to obtain them?
Thank you.
Best regards
On Thu, Sep 15, 2022 at 10:53 PM Corby Dawson via time-nuts
time-nuts@lists.febo.com wrote:
Here are details on some tests I ran on replacement lamps for the
HP5065A.
Cheers!
Corby_______________________________________________
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
--
/* Lin Ke-Fong
- anotherlin@gmail.com
- I always do what I say, especially if it's something stupid.
*/
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
Some anamorphic beam shaping via a prism or equivalent may be required for efficient use of the laser output.
The datasheet indicates that they are not truly longitudinal single mode except at a particular junction temperature which varies from one chip to the next.
Using some external feedback from an external cavity may be useful in stabilising operation on a single mode without mode jumps. Typical mode spacing appears to be somewhere around 0.5nm or so.
Random mode jumping to a wavelength 0.5nm or so from the desired wavelength will likely impact operation as a pump diode. Careful selection of laser diode, its temperature and excitation current will be required for successful operation.
Bruce
On 19/09/2022 03:05 Stephen C. Menasian via time-nuts time-nuts@lists.febo.com wrote:
As a bit of background - When I was an undergraduate, I worked with a
group using optically pumped 87Rb to orient hydrogen via spin exchange to
measure the hydrogen hyperfine frequency. At that time, our Rb lamps were
RF excited 1 cm dia spherical bulbs. There was a bit of black magic in
the choice and type of noble gas used to maintain the discharge. Rb vapor
pressure was controlled by bulb temperature. I don't believe there was
any teflon coating in the lamps; teflon coating was used, however, in the
optical pumping cell to reduce collisional disorientation and consequent
broadening. At that time we used circular polarizers to achieve the
pumping effect. I note that the SRS Rb standard uses intensity pumping,
which I consider cruder.
I note that Laser diodes in the correct wavelength range are available
for under $20.00 (Rohm RLD78NZM5 and similar) from Digikey and Mouser.
These have 10 mW optical single mode output. Most laser diodes are easily
tuned over a small range; the well defined beam and its polarization
characteristics could provide a significant advantage over a gas
discharge lamp. Intensity stabilization would probably be necessary to
achieve the low noise level necessary for optical pumping. These laser
diodes include an integrated photodetector to facilitate stabilization.
Anyway, it might be worth looking into them as lamp replacements.
Stephen Menasian
On Fri, 16 Sep 2022 22:59:22 +0200
Ke-Fong Lin via time-nuts time-nuts@lists.febo.com wrote:
Hi Corby,
It seems that all the lamps tested are from used rubidium standards.
Is it possible to buy "off the shelf" rubidium lamps somewhere?
Or is it so "specialized" that's only way to obtain them?
Thank you.Best regards
On Thu, Sep 15, 2022 at 10:53 PM Corby Dawson via time-nuts
time-nuts@lists.febo.com wrote:Here are details on some tests I ran on replacement lamps for the
HP5065A.Cheers!
Corby_______________________________________________
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com--
/* Lin Ke-Fong
- anotherlin@gmail.com
- I always do what I say, especially if it's something stupid.
*/
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
Usually a separate Rb87 gas cell is required to stabilise the laser wavelength: http://tf.nist.gov/general/pdf/1219.pdf
Bruce
On 19/09/2022 14:49 Bruce Griffiths via time-nuts time-nuts@lists.febo.com wrote:
Some anamorphic beam shaping via a prism or equivalent may be required for efficient use of the laser output.
The datasheet indicates that they are not truly longitudinal single mode except at a particular junction temperature which varies from one chip to the next.
Using some external feedback from an external cavity may be useful in stabilising operation on a single mode without mode jumps. Typical mode spacing appears to be somewhere around 0.5nm or so.
Random mode jumping to a wavelength 0.5nm or so from the desired wavelength will likely impact operation as a pump diode. Careful selection of laser diode, its temperature and excitation current will be required for successful operation.
Bruce
On 19/09/2022 03:05 Stephen C. Menasian via time-nuts time-nuts@lists.febo.com wrote:
As a bit of background - When I was an undergraduate, I worked with a
group using optically pumped 87Rb to orient hydrogen via spin exchange to
measure the hydrogen hyperfine frequency. At that time, our Rb lamps were
RF excited 1 cm dia spherical bulbs. There was a bit of black magic in
the choice and type of noble gas used to maintain the discharge. Rb vapor
pressure was controlled by bulb temperature. I don't believe there was
any teflon coating in the lamps; teflon coating was used, however, in the
optical pumping cell to reduce collisional disorientation and consequent
broadening. At that time we used circular polarizers to achieve the
pumping effect. I note that the SRS Rb standard uses intensity pumping,
which I consider cruder.I note that Laser diodes in the correct wavelength range are available
for under $20.00 (Rohm RLD78NZM5 and similar) from Digikey and Mouser.
These have 10 mW optical single mode output. Most laser diodes are easily
tuned over a small range; the well defined beam and its polarization
characteristics could provide a significant advantage over a gas
discharge lamp. Intensity stabilization would probably be necessary to
achieve the low noise level necessary for optical pumping. These laser
diodes include an integrated photodetector to facilitate stabilization.Anyway, it might be worth looking into them as lamp replacements.
Stephen Menasian
On Fri, 16 Sep 2022 22:59:22 +0200
Ke-Fong Lin via time-nuts time-nuts@lists.febo.com wrote:Hi Corby,
It seems that all the lamps tested are from used rubidium standards.
Is it possible to buy "off the shelf" rubidium lamps somewhere?
Or is it so "specialized" that's only way to obtain them?
Thank you.Best regards
On Thu, Sep 15, 2022 at 10:53 PM Corby Dawson via time-nuts
time-nuts@lists.febo.com wrote:Here are details on some tests I ran on replacement lamps for the
HP5065A.Cheers!
Corby_______________________________________________
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com--
/* Lin Ke-Fong
- anotherlin@gmail.com
- I always do what I say, especially if it's something stupid.
*/
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