[time-nuts] Question about SA.33 Rb clock

Tom Van Baak tvb at LeapSecond.com
Thu Oct 12 12:06:52 EDT 2017


Hi Hui Zhang,

> in the paper CSAC was described that it is based on CPT technology
> My question is the SA.3x(or SA.2x) also used this method?

Yes. Here's another good read; and it also includes photos of the inside of your SA.33:

http://www-users.york.ac.uk/~jke1/Atomic_Clocks/Papers/Commercial%20CPT.pdf

> In my impression the SA.3x series clock is called Rubidium clock,
> and the SA.45 is a real Cesium CSAC?

Your use of the phrase "real cesium" may be the source of your confusion. The SA.3x uses rubidium and the SA.4x uses cesium. They are all real atoms. These modern MAC / CSAC atomic standards compete with high-end DOCXO quartz oscillators with respect to factors like temperature, stability, and drift. They do not compete with traditional laboratory rubidium or cesium standards.

You may be thinking that because some CPT clocks use cesium instead of rubidium that they are special or more accurate, but this is not the case. None of these compact low-power  laser / VCSEL / CPT -based frequency standards are primary standards.

/tvb

----- Original Message ----- 
From: "Jar Sun via time-nuts" <time-nuts at febo.com>
To: <time-nuts at febo.com>
Sent: Saturday, October 07, 2017 8:27 PM
Subject: [time-nuts] Question about SA.33 Rb clock


Dear group: I have got a SA.33 Rb module from a second hand GPS clock, at first it works well, but soon after it was damaged that beacuse I was trying to install a heat sink on it, unfortunately I used screws which its size too long, so maybe the screws drilled into inside Rb lamp or inside circuit something? I don't know.
I am not expecting this Rb can be receoveyed, I am just hope there is no some martirial hamfully leaked out. TVB gave me some information about this Rb module and a papers on this website:
http://tycho.usno.navy.mil/ptti/2002papers/paper52.pdf
I have read the paper for two times, but I am confused now, the paper described a principle of CSAC clock in 2002, in the papger CSAC was described that it is based on CPT technology, and the CPT is based on a VCSEL and a very small Cesium Cell and other implement necessarily. My question is the SA.3x(or SA.2x) also used this method? In my impression the SA.3x series clock is called Rubidium clock, and the SA.45 is a real Cesium CSAC? So if SA.3x or SA.2x used the technique which mentioned in paper52, can we say there is some Cesium material in SA.3x? I am totally confused, do anyone can give me some advice? Any information will be appreciated, Thanks a lot.
Regards.
Hui Zhang
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