[time-nuts] Symmetricom CSAC is Cs acting like a Rb unit

Bob Camp lists at rtty.us
Tue Jan 18 22:10:54 UTC 2011


Simply having cesium in it does not make it a primary standard. Since it's
more like a rubidium than anything else, it's a lot easier to think of it as
a "really small low power rubidium". One other advantage it may have is that
the LED may have a longer life than a normal "light bulb" source. I suspect
it's a little early to forecast 20 year (or not) life on these yet. 


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of WB6BNQ
Sent: Tuesday, January 18, 2011 5:03 PM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Symmetricom CSAC is Cs acting like a Rb unit

To the list,

If you listen carefully to the Symmetricom slide show, particularly page 3,
it will tell you all you need to


You will discover that that it is indeed a Cesium operated device.  HOWEVER
!  It is operated in the same manner
as a Rubidium device.  Doing such does NOT make it a primary standard.

In a Cesium Primary standard, a beam of Cesium atoms are energized to a
higher state whose decay give off a
photon of light such that being on frequecy produces more light to the
detector.  In the Rb system, the Rb cell
acts simply as a light filter such that when on frequency the light level is
reduced as seen by the detector.

This Symmetricom CSAC device uses the same process as the Rb method above.
It uses a laser to push light through
a chamber of Cesium gas.  This Cesium gas is acting as a simple light
filter.  So in its current state it will
not rival it superior cousins except in size and power comsumption and
possibly price for performance in some


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