[time-nuts] hm H Maser

[Bruce Griffiths]

For a rubidium vpour standard a cavity is essential, one could always use a 
microwave horn to illuminate the cell in an anechoic chamber.
Using an integrating sphere can enhance the contrast of the optical signal 
significantly.

http://www.princeton.edu/physics/graduate-program/theses/theses-from-2011-1/bmcguyer_dissertation.pdf

https://infoscience.epfl.ch/record/178228/files/IFCS_Invited_Talk_Finalpdf.pdf

https://doc.rero.ch/record/32317/files/00002318.pdf

http://tf.nist.gov/general/pdf/1154.pdf

http://tf.boulder.nist.gov/general/pdf/1663.pdf


Bruce
On Sunday, January 08, 2017 10:20:33 PM Bruce Griffiths wrote:
> Possible sources of Rubium vapour
> 
cells:https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1470
> 
> http://www.precisionglassblowing.com/custom-solutions/optical-glassware/vapo
> r-wavelength-reference-cells/
> 
> https://www.sacher-laser.com/home/lab-equipment/spectroscopy/reference_gas_a
> nd_vapor_cells/reference_gas_and_vapor_cells.html
> 
> 
> Bruce
> 
>     On Monday, 9 January 2017 11:14 AM, Bruce Griffiths
> <bruce.griffiths at xtra.co.nz> wrote:
> 
> 
>  Bob
> As long as one stays away from CPT and merely uses the laser as a
> replacement for the traditional rubidium lamp plus filters it should be
> easy enough as one doesnt need to modulate the laser at 3.4 GHz.I was
> thinking something along the lines of the recent PhD thesis that gave all
> the detail required to duplicate their low noise rubidium standard that 
was
> quieter than am HP5065.One could easily substitute ones own ECDL 
(These can
> easily be constructed from commercially available parts) and improve
> somewhat on the performance (The oven design of most commercial 
ECDLs seems
> suboptimal). Bruce
> 
>     On Monday, 9 January 2017 10:23 AM, Bob Camp <kb8tq at n1k.org> 
wrote:
> 
> 
>  Hi
> 
> The large diameter Rb cells are a bit harder to come by than the more
> generic telecom sized cells. I suspect you are correct and they are out
> there from somebody.. The real advantage you would have with an Rb is 
that
> the design you do is gigantic compared to what everybody is doing 
today.
> Their constraints are not your constraints.
> 
> Based on the laser driven Rb on my bench …. don’t bother with that part 
of
> it. It is indeed doable. Doing it in a fashion that gives you a better
> standard …. not really easy at all.
> 
> Bob
> 
> > On Jan 8, 2017, at 3:55 PM, Bruce Griffiths 
<bruce.griffiths at xtra.co.nz>
> > wrote:
> > 
> > The rubidium standard appears much more manageable given that 
the cavity
> > dimensions are somewhat more compact and rubidium vapour cells 
are
> > readily available. Substituting a laser for the lamp should also help in
> > improving the reliability. However an ECDL laser locked to a rubidium
> > line is required for a double resonance setup. Building ones own ECDL
> > doesn't appear to be particularly daunting, however low noise drive
> > electronics will be required. All the necessary optics are off the shelf
> > items. One still has the issue of  the frequency pulling due to the
> > presence of the vapour cell. Bruce
> > 
> > On Sunday, January 08, 2017 10:22:54 AM you wrote:
> > > Hi
> > > 
> > > I guess the question then would be:
> > > 
> > > Is a H Maser that runs 6.6 x 10^-12 at 1 second worth the trouble?
> > > 
> > > With 100 KHz / C temperature coefficients running around, getting
> > > good stability in a real world setting at 1 day will be “interesting”.
> > > 
> > > Just for reference:  The MH-2010 data sheet shows 1.5x10^-13 at
> > > 1 second for the “cheap” version and 8x10^-14 at one second for
> > > the low noise version.  Data showing the 5065 Rb at 1x10^-12 at
> > > 1 second is running around on various web sites.
> > > 
> > > The NIST paper suggests that they made several prototypes before
> > > they got one good one working. That’s a lot of “fun and games” with
> > > ceramic machine lathes and Rb magnetometers…..
> > > 
> > > The punch line being - would the same effort / cost / many years of 
time
> > > be
> > > more fruitful (ADEV wise) doing a large package Rb (like a 5065) ? 
> > > Based
> > > on the number of people making them in volume over the years, 
Rb’s
> > > appear
> > > to be the easier item to debug, design, and build.
> > > 
> > > Bob
> > > 
> > > > On Jan 8, 2017, at 6:01 AM, Bruce Griffiths
> > > > <bruce.griffiths at xtra.co.nz>
> > > > wrote:
> > > > 
> > > > You could try a cavity like the one
> > > > in;http://tf.nist.gov/general/pdf/156.pdf
> > > > 
> > > > This avoids the requirement for a fused quartz storage bulb.
> > > > Bruce
> > > >
> > > >    On Sunday, 8 January 2017 11:33 PM, timeok 
<timeok at timeok.it> wrote:
> > > > Hi,
> > > > the thought of being able to work on building a H Maser has 
always
> > > > accompanied me in recent years. I fully understand the many
> > > > difficulties
> > > > of this project and also the necessity of a work team. Maybe a 
Passive
> > > > Maser would be easiest to implement, but I do not know in detail 
the
> > > > processes of construction of the physical part of the 
interrogation.