>
>Rich, see my questions below:
>
>----------
>From: measures[SMTP:2@vc.net]
>Sent: Sunday, March 05, 2000 3:11 PM
>To: Michael Tope; AMPS; 'W8JI@contesting.com'
>Subject: RE: [AMPS] Network analysis of suppressors
>
>>>
>>> Borrow a geiger counter, Mr. Rauch, and tune in on what's happening on the
>>> upper frequencies. Be not surprised if you occasionally encounter some
>>> humungous signals.
>>
>>Rich or Tom, please forgive me if I misrepresent any of your
>>claims as I haven't been following this debate very closely
>>and hence am not fully versed in the details of your respective
>>positions. Regarding the idea that radiation single events can
>>cause significant current to flow in a high power vacuum tube,
>>this seems unlikely to me.
>
>As it first did to me, Mike. My guess is that a photon strikes an atom,
>knocking loose a current carrier/electron, thereby causingthe tube to
>briefly conduct. This causes several kV to appear across the bias
>contacts, which arc. The contacts form a metal vapour arc. Since the
>voltage drop across such an arc is low, the amplifier tube switches out
>of cutoff bias and an event could take place.
>
>cheers
>
>Rich, a couple of questions?
>
>1. Are my assumptions about the operating conditions
>in the above scenario correct - B+ = ON, Filament = ON,
>BIAS = CUTOFF?
yes
>
>2. From where in the tube does the free carrier (electron)
>emanate - the surface of the cathode, the control grid,
>the anode, residual gas in tube?
>
Virtually anything. . Gamma rays and secondary cosmic rays knock
electrons loose from atoms that get in the way of their path.
>3. What is the direction of the current flow that is created
>by the free carriers - cathode to grid, cathode to anode, grid
>to anode?
cathode to anode. The electrons would have to have enough velocity to
get past the -25v or so at the grid.
>
>4. How do a few electrons create a potential change of several
>thousand volts across the bias relay contacts?
Since V = Q/C,
>seems like it would take many electrons to raise the voltage
>across the bias relay contacts to a few thousand volts (the
>charge on an electron is around 10E-19 coulombs). How many
>electrons are we talking? Is the bandgap energy involved in the
>carrier release consistent with radiation events of probable
>magnitude (or are we talking about real "big bang" energies?)
>
The typical potential across the bias contacts is c. 25v and the drop
across the cutoff tube is several kV. The initial arc across the bias
contacts is caused by the potential across the tube dropping from several
kV to a low value due to the free electrons.
>
>
>Thanks,
>
>Mike, W4EF.............
>
>
>--
>FAQ on WWW: http://www.contesting.com/ampsfaq.html
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>Search: http://www.contesting.com/km9p/search.htm
>
>
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|