[time-nuts] Input voltage for Zeeman on 5061A

Sat Jan 22 15:06:36 EST 2005

Hi John:

I think it was in the HP 5060 manual that they recommended that you 
connect a large external analog meter when doing the Zeeman C field 
setting so that you could see the peak easier than on the 1 inch meter 
on the front panel.

I've been reading up on Zeeman and find that he was the grad student of 
Lorentz, Zeeman did the work and Lorentz came up with the theory and 
they shared the Nobel prize in 1902 (the second year of the Nobel 
prize).  Their theory was based on a new particle called the 
"electron".  By using the Zeeman effect they could compute some of it's 
properties and confirm that it was the same particle that was used in 
Cathode Ray Tubes.  But they did not understand the quantum mechanics 
aspects relating to up and down electron spins that came later.  I think 
to compute the Zeeman frequencies requires the use of quantum 
mechanics.  What the Zeeman effect is correlating the magnetic field 
strength and the splitting of a single spectral line allowing adjustment 
or measuring the magnetic field.

Once I get my 4060 tweaked and know the C field based on GPS, then I'll 
do some Zeeman experiments.

Tom:

I'm curious as to how close you get using the Zeeman method.  Do you 
have any data showing Zeeman frequency vs. Source frequency for HP 
and/or FTS tubes?

Have Fun,

Brooke Clarke, N6GCE

-- 
w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
http://www.precisionclock.com

John Ackermann N8UR wrote:

> The meter readings I'm seeing are valleys of about 18 and the major 
> peak of about 22.  The secondary peaks are about 20.  I'm pretty sure 
> I'm looking at the close in peaks.
>
> However, when I did that check the loop-closed beam current was about 
> 17.  After taking those measurements, I bumped the beam I adjustment 
> to get it up to 20; the 2nd harmonic was reading 40 both before and 
> after that minor adjustment.  I suspect that having slightly higher 
> current to begin with might help make the peaks more pronounced.
>
> One thing that's slightly confusing in the manual is the amplitude 
> setting of the audio oscillator.  The book says to start with zero and 
> increase to the first peak.  Well, when starting at zero there's 
> actually a decrease in current as you crank the amplitude up, but I 
> was able to spot a small peak at about 800mv RMS, so that's where I 
> left the amplitude setting.
>
> At the moment, I'm doing a check against GPS and Loran at the value I 
> found (which isn't too far off what Corby set the unit to before 
> shipment -- it's at about 4.90 now versus 5.06 before).  I want to let 
> that run for at least a few more hours to get a sense of how close it 
> is.  After that, I'll go back to experimenting.
>
> John
> ----
> Tom Van Baak wrote:
>
>> John,
>>
>> Can you quantify that? How many minor divisions
>> on the C-field dial and what meter levels do you get
>> for the 3 peaks and 2 valleys between the peaks?
>>
>> Also try recording to 9 or 10 digits the 5 MHz output
>> at each peak/valley.
>>
>> I want to clarify something mentioned a while back.
>> The peak(s) and valleys you see when performing a
>> Zeeman calibration are the narrow ~500 Hz wide
>> center peak. See:
>> http://www.leapsecond.com/pages/cspeak/image003.gif
>> and
>> http://www.leapsecond.com/pages/cspeak/image004.gif
>>
>> These are not the broad ~40 kHz separated 7 peaks as in:
>> http://www.leapsecond.com/pages/cspeak/image001.gif
>>
>> /tvb
>>
>> ----- Original Message -----
>> From: "John Ackermann N8UR" <jra at febo.com>
>> To: "Discussion of precise time and frequency measurement"
>> <time-nuts at febo.com>
>> Sent: Saturday, January 22, 2005 08:57
>> Subject: Re: [time-nuts] Input voltage for Zeeman on 5061A
>>
>>
>>  
>>
>>> I tried the 42.82kHz frequency and wasn't able to see any peaks or dips
>>> at all.  53.53 gives peaks and dips, but not very pronounced.
>>>
>>> John
>>> ----
>>>
>>> Chuck Harris wrote:
>>>
>>>   
>>>
>>>> The Zeeman frequency is a characteristic of the tube.  Most FTS tubes
>>>> have their main Zeeman peak at 42.820kHz, and the two peaks on either
>>>> side are at 41.800kHz, and 43.800kHz.
>>>>
>>>> 1 Vrms is what the 5061 wants to see (The Zeeman input is a 50 ohm 
>>>> load
>>>> IIRC).
>>>>
>>>> -Chuck
>>>>
>>>> John Ackermann N8UR wrote:
>>>>
>>>>     
>>>>
>>>>> Anyone know how much voltage you need to drive the Zeeman input on
>>>>> the 5061A?  I just tried to set mine and found that the maximum
>>>>> output from my 3325A (3V RMS) was barely enough to see any wiggling
>>>>> at all on the beam current meter  I have another generator that goes
>>>>> up to 6V and that got me a bit more, but even then only a few meter
>>>>> divisions between peak and dip.
>>>>>
>>>>> Either I need a heftier generator (or maybe an impedance step-up), or
>>>>> we're back to the question of what is the right Zeeman frequency for
>>>>> an FTS tube in an HP chassis.
>>>>>
>>>>> Thanks,
>>>>>
>>>>> John
>>>>>       
>>>>
>>
>>
>>
>>
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>>  
>>
>
>
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