[Amps] Voodoo Magnetic Fields

[2]

>2 wrote:
>>>If the arc is extinguished quickly and not too much energy is dumped
>>>into the tube, the tube can recover completely. There may not be much
>>>visible evidence that the arc ever occurred (depending on the tube
>>>construction). If the tube was hot, the getter can collect the gas
>>>within a few seconds.
>>
>>**  reference please
>
>I got the old phys chem textbooks out of the attic and calculated that 
>the mean speed of a typical light gas atom originating at a temperature 
>of about 500C is of the order of 1000 m/s.
>
>That means that the dwell time of a gas atom released into a typical 
>inter-electrode space (dimension ~1cm) is ~10 microseconds. That's 
>plenty of time to become involved in a gas arc, if there are enough 
>other atoms around.
>
>Within the next second, that same atom rattling around inside a 3-500Z 
>of radius ~10cm could make anything up to several thousand collisions 
>with all the surfaces inside the tube. If it hits the glass, there is a 
>high probability that it will bounce off. But if it hits the getter, 
>there is a high probability that it will be trapped on the surface.
>
>So within one second - time enough for several thousand attempts to trap 
>each atom - almost all the released atoms *will* have been trapped, and 
>the vacuum will have returned to normal.
>
>This is totally consistent with John Lyles' observation of a "small blip 
>on the ion gauge" in pumped tubes whose pressure is being continuously 
>monitored.
>
**  The tubes John Lyles works with have an ion pump.  3-500Zs do not.  
Also, you have not yet explained cold gettering.   I have a 3-400Z that 
has exhibited c. 10uA of leakage @8kV for the last 7-years.  When should 
the gettering process be finished?
>
>Well, they did promise me that the kinetic theory of gases would come in 
>handy one day. They just didn't tell me it would take 35 years...
>
>-- 
>73 from Ian G3SEK

-  R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, 
www.vcnet.com/measures.  
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