[NLRS] Fwd: Re: [scarc] "I shall return ..."

Tue May 29 00:32:41 EDT 2012

I don't think so. Even in a vacuum, electron velocity depends on the 
accelerating electric field. Electrons have mass and that makes 
accelerating them in a vacuum, air, or semiconductor take energy. Then 
they dissipate that kinetic energy when they strike the anode. In the 
4CV100,000C used in the Collins 821A-1 PA, electron velocity with 60 KV 
peak RF + modulation they figured the electron velocity as about 0.1C. 
We broke open a blown tube or two and found the electron impact against 
the copper anode showed the shadows of the aligned grids and the dents 
were deep enough to feel with ordinary fingers. Probably a few 
thousandths of an inch.

In this proposed scheme the "tube" size is smaller than the atomic 
spacing in ordinary air so they can neglect to enclose the electron. 
space. I think they haven't considered the kinetic energy when the 
electron hits the pico (or single atom) scale anode or that their device 
may only work with a dozen electrons at a time and that makes for a 
lousy linear amplifier stage when the control grid can't reject half an 
electron, but has to reject whole electrons. The transfer function will 
be like that of an A/D converter, discrete steps. Then it appears to me 
that the scale will be so small that a gamma ray particle will change 
the stage operation like it does solid state memory, so it will be 
affected by EMP and cosmic rays, just like solid state simply because 
the scale of the active device is comparable to the ionized cosmic 
particles.

73, Jerry, K0CQ

On 5/28/2012 12:22 PM, S. Earl Jarosh wrote:
> Jerry,
>
> When is a tube not a tube?  Effectively they have developed a vacuumless
> tube technology eliminating the need for a substrate at the nanometer level
> and therefore eliminating the velocity aspect of semiconductors.  While only
> in proof of concept stage it could provide a whole new scenario in speed and
> jitter issues in technology.  It will be interesting to see where this can
> go.
>
>
> S. Earl Jarosh, N0HZ
> Cell:  612.868.1313
> Off:   763.545.3275
> Home:  763.546.7897
> Fax:   763.546.7897
> earl at moneycenters.com
>
>
> -----Original Message-----
> From: nlrs-bounces at mailman.qth.net [mailto:nlrs-bounces at mailman.qth.net] On
> Behalf Of Dr. Gerald N. Johnson
> Sent: Friday, May 25, 2012 10:53 PM
> To: NLRS Reflector
> Subject: [NLRS] Fwd: Re: [scarc] "I shall return ..."
>
>
>
>
>
> -------- Original Message --------
> Subject: Re: [scarc] "I shall return ..."
> Date: Fri, 25 May 2012 16:58:20 -0500
> From: Dr. Gerald N. Johnson<geraldj at weather.net>
> Reply-To: geraldj at weather.net
> To: scarc at iastate.edu
>
> Tubes have not left very high power transmitters yet.
>
> As for receiving and computing, there is more computer power today in a
> volume the size of a 6SN7GT than there was in a bushel sized computer a
> decade ago, and more computer power in the volume of that tube than all the
> world's computers two decades ago all together. Today the package is
> increasingly important to make the hardware big enough for human fingers to
> handle while the contents gets to have a 2 GHz CPU with 100 GB of memory in
> two chip scale packages maybe as big as 1/2" square by 1/16th inch thick but
> probably smaller this week.
>
> Part of the problems with EMP and cosmic particles in solid state is that
> the geometry of the parts is the size of those atomic particles (with new
> semiconductor using 12 micron geometry next year) so that the passage of
> that atomic particle changes stored energy (as most memory is based on
> stored charges) with very low voltage supplies like 1.2 volts to keep power
> consumption down because the capacitive gates take more drive power with
> larger voltage swings to charge in a few picoseconds.
>
> The only way tubes could be competitive would be if the tube geometry was as
> small working at similar low voltages, and then it would be as susceptible
> to EMP and cosmic particles as semiconductors.
>
> As for electron mobility, there are commercial MMICs made for the 1/2 to
> 1 TeraHz region and there never have been tubes made for that frequency
> range. Gallium Arsenide has pretty good electron mobility and when the
> active device is only 20 microns across, it doesn't take long for that
> electron to make the passage.
>
> 73, Jerry, K0CQ
>
> On 5/25/2012 1:55 PM, W0WOI at aol.com wrote:
>> *Return of the Vacuum Tube *
>>
>> Vacuum tubes suffered a slow death during the 1950s and '60s thanks to
>> the invention of the transistor.specifically, the ability to
>> mass-produce transistors by chemically engraving, or etching, pieces
>> of silicon. Transistors were smaller, cheaper, and longer lasting.
>> They could also be packed into microchips to switch on and off
>> according to different, complex inputs, paving the way for smaller,
>> more powerful computers.
>> But transistors weren't better in all respects. Electrons move more
>> slowly in a solid than in a vacuum, which means transistors are
>> generally slower than vacuum tubes; as a result, computing isn't as
>> quick as it could be. What's more, semiconductors are susceptible to
>> strong radiation, which can disrupt the atomic structure of the
>> silicon such that the charges no longer move properly. That's a big
>> problem for the military and NASA, which need their technology to work
>> in radiation-harsh environments such as outer space.
>> http://news.sciencemag.org/sciencenow/2012/05/return-of-the-vacuum-tub
>> e.html
>>
>>
>>
>>
>> _______________________________________________
>> Story County Amateur Radio Club email list scarc mailing list
>> scarc at iastate.edu https://mailman.iastate.edu/mailman/listinfo/scarc
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