good books on vacuum tube design? - Page 1
Forum section: electronics / projects

author: sarepairman2
author_rank: Frequent Contributor
timestamp: January 27, 2016, 02:27:24 am
content: ?

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 27, 2016, 02:41:36 am
content: How to design the tubes themselves? Or *with* tubes? Design *what*? Audio amplifiers in the single digit watt range? Kilowatt range? RF amplifiers? Photomultipliers? Microwave stuff? Backward wave oscillators to the THz range?

author: sarepairman2
author_rank: Frequent Contributor
timestamp: January 27, 2016, 03:29:31 am
content: physics level vacuum tube stuff

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 27, 2016, 03:36:49 am
content: Quote from: sarepairman2 on January 27, 2016, 03:29:31 amThe RCA receiving tube manual is good.http://www.tubebooks.org/tubedata/RC30.pdfThere's probably a MIT Rad Lab volume on that too.

author: joeqsmith
author_rank: Super Contributor
timestamp: January 27, 2016, 03:40:36 am
content: First suggestion without knowing what you are looking for:ARRL Handbooks, something pre 1960sRCA Receiving Tube ManualIf you really want to see some good info, try and find a copy of:Applications Manual for Computing Amplifiers for Modelling Measuring Manipulating & Much ElseIt's more an analog designers guide with a sprinkle of tubes....

author: sarepairman2
author_rank: Frequent Contributor
timestamp: January 27, 2016, 03:45:28 am
content: thank you, that is a good starti think i have an idea that might bring the vacuum tube back to life

author: AF6LJ
author_rank: Unknown
timestamp: January 27, 2016, 03:51:22 am
content: Quote from: Alex Eisenhut on January 27, 2016, 03:36:49 amI second thatI have it in both hard, and soft copy.Very useful, not just for the theory, there is an application section in the back.

author: HAL-42b
author_rank: Frequent Contributor
timestamp: January 27, 2016, 03:58:55 am
content: Mike used to have a very good one on his site, don't know if he still keeps it there.Gas Discharge Tubes - Dr J. G. W. Mulder.

author: AF6LJ
author_rank: Unknown
timestamp: January 27, 2016, 04:03:26 am
content: Another good suggestion is Bill Orr's Radio handbook.In some respects better than the ARRL Handbooks.

author: chris_leyson
author_rank: Super Contributor
timestamp: January 27, 2016, 05:34:39 am
content: A few that spring to mind, all on my bookshelf, but 200 miles awayThe Radiotron Designer's Handbook by J. Langford-Smith, It was reprinted a few years ago, can't find the ISBN number grrrUniversal vade-mecum if you want data sheets still available I thinkValve Amplifiers by Morgan Jones, might still have that, dunnoPrinciples of Electron Tubes, Herbert Reich 1941 - A classc. Can't find a copy of that one, seems the audiophiles grab those.Just found a scanned copycheck links below, i know what I'm going to be reading this weekendhttp://www.qsl.net/va3iul/Files/Old_Radio_Frequency_Books.htmhttp://www.tubebooks.org/technical_books_online.htm

author: daqq
author_rank: Super Contributor
timestamp: January 27, 2016, 05:51:50 am
content: Philip Parker : Electronics, 1950I don't know if you can find it online, I have a paper copy. If you run into one copy, definitely buy it. See:https://www.eevblog.com/forum/chat/1950s-book-copyright-can-i-scan-this-and-upload-it/

author: Pjotr
author_rank: Frequent Contributor
timestamp: January 27, 2016, 07:19:28 am
content: Quote from: sarepairman2 on January 27, 2016, 03:29:31 amFor the real physics of vacuum tubes there are several good pre WW2 books. For that you need to go to the library of the physics department of a (technical) university. Some of those books have nice pictures that illustrate the static fields in a tube with the use of rubber sheets... I have not found such material on the web.

author: Cubdriver
author_rank: Unknown
timestamp: January 27, 2016, 06:46:23 pm
content: Some from my shelf:Vacuum Tubes - Karl Spangenberg - 1948Electronic Circuits and Tubes - Cruft Electronics Staff - 1947Vacuum Tube Circuits - L. B. Arguimbau - 1948And of course the aforementioned Radiotron Designer's Handbooks.-Pat

author: Cubdriver
author_rank: Unknown
timestamp: January 27, 2016, 06:51:48 pm
content: Quote from: chris_leyson on January 27, 2016, 05:34:39 amThis one seems to be available as a reprint as of 2013 in both soft and hardcover on Amazon. I'll be looking into it...http://www.amazon.com/Principles-Electron-Tubes-Herbert-Reich/dp/1258664062/ref=tmm_hrd_swatch_0?_encoding=UTF8&qid=1453920562&sr=8-1-Pat

author: oldway
author_rank: Super Contributor
timestamp: January 27, 2016, 07:24:15 pm
content: Quote from: chris_leyson on January 27, 2016, 05:34:39 amI have the Radio designer's handbook fourth edition by F. LANGFORD-SMITHFirst published (Australia) : 1934Second edition : 1935Third edition : 1940Fourth edition: 1953BKS1635/53

author: uncle_bob
author_rank: Unknown
timestamp: January 27, 2016, 07:31:34 pm
content: Quote from: sarepairman2 on January 27, 2016, 03:29:31 amHiAs in the physics of how to do the insides of a vacuum tube.Are you planning to run a hot cathode or not?Bob

author: sarepairman2
author_rank: Frequent Contributor
timestamp: January 28, 2016, 12:31:20 am
content: Quote from: uncle_bob on January 27, 2016, 07:31:34 pmi have no idea, I have a fair bit of reading cut out for me with all these posts, maybe i can tell you in a month lol

author: Stray Electron
author_rank: Super Contributor
timestamp: January 28, 2016, 02:43:21 am
content: 'Gaseous Conductors' by James D. Cobine, McGraw Hill, 1941. It's one of those good OLD text books that really teaches you the theory and the practice. But good luck finding a copy. It took three years for me to find one and I had buy someone's entire library to get it! Despite the slightly misleading title, it goes into the characteristics of fluorescent lights, vacuum and partial vacuums, inert gasses, hydrogen gas (thyratrons), Mercury vapor, etc as well as the nature of the anode and cathode and space charge. Unlike radio tube books that deal with VT amplifiers and the like, this book covers every aspect of electron flow inside of tubes undermanydifferent circumstances. They do discuss radio type tubes but that is just one single use.

author: HAL-42b
author_rank: Frequent Contributor
timestamp: January 28, 2016, 03:24:02 am
content: Conduction of electricity through gases - J.J. Thomsonavailable at arxive.org

author: sarepairman2
author_rank: Frequent Contributor
timestamp: January 28, 2016, 03:28:08 am
content: Quote from: Stray Electron on January 28, 2016, 02:43:21 amthis sounds like exactly what I am looking for.I find some of the old texts extremely good, they give you the information in a manner that it is much easier to detect the concept, because it is not obfuscated by too many profitable applicationsmaybe the old authors were more excited by the stuff toois this it?http://product.half.ebay.com/Gaseous-Conductors-Theory-and-Engineering-Applications-by-James-D-Cobine-1941-Paperback/48999312&tg=info

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 28, 2016, 04:11:57 am
content: http://www.tubebooks.org/Books/Atwood/RCA%201940%20Vacuum%20Tube%20Design.pdfIt's in the title!

author: sarepairman2
author_rank: Frequent Contributor
timestamp: January 28, 2016, 07:36:31 am
content: ok i bought that old booki think i will start with that low level physics book governing the gas behavior before i get into the other literature

author: uncle_bob
author_rank: Unknown
timestamp: January 28, 2016, 06:27:14 pm
content: Quote from: sarepairman2 on January 28, 2016, 12:31:20 amHiWell, it's one of many very big differences in which way you go with this. I've worked with a number of tube designers. They tend to specialize fairly early in their training and spend the next 5 or 10 years learning the trade in their sub-area.More or less:Hot cathode vacuum based tubes are one area.Gas filled (power) tubes are a different areaCold cathode devices are a different area stillEach has it's application. Each has it's own physics. Each has a specific type of manufacturing plant designed to make them. There are indeed many further sub specializations. A tube for an audio pre-amp is a bit different than the output tube in a 100KW transmitter. Both are vacuum tubes with hot cathodes. The guys who design one are not the same as the guys who design the other ones. Same is true of the manufacturing lines.It might help if we had some idea of what you are trying to do. Tubes get (or got) used in a *lot* of things ....Bob

author: Paul Rose
author_rank: Regular Contributor
timestamp: January 28, 2016, 11:51:02 pm
content: If it comes to circuit design with existing tubes/valves (not development of the devices themselves), I've been meaning to look at:"Hollow State Design" by Grayson Evans ( ISBN 978-1300965213 )It is actually a recent book ( 2013 ).Somewhat oriented toward radio amateurs ( RF and Audio ).

author: Stray Electron
author_rank: Super Contributor
timestamp: January 29, 2016, 12:49:06 am
content: Quote from: sarepairman2 on January 28, 2016, 03:28:08 amThat looks like it. I didn't know that Dover had reprinted it but they have reprinted other classic text books such as the MIT Rad Lab series.

author: calexanian
author_rank: Super Contributor
timestamp: January 29, 2016, 05:37:35 am
content: Gas behavior only applies to some fringe characteristics of tube operation. Unless you are talking about ionization conducting tubes such as thyratron's and gas rectifiers, and discharge tubes such as regulators. Neon lights, nixies, and gas discharge tubes can be grouped into this category as well. Otherwise gas is to be avoided.

author: woodchips
author_rank: Frequent Contributor
timestamp: January 29, 2016, 10:28:38 am
content: Ah, yes, interesting question. Seems the query is about the design OF, not the design WITH vacuum tubes.Some years ago I looked through a collection of valves I had built up. I had no interest in them and wondered what to do with them, but ended up on some audio web sites and realised they were much more valuable than I ever guessed. More reading around and discovered that a long plate ECC83 was much better than a short plate, but why? I started reading around the subject of valve design but found almost nothing. Why should modern equivalents be so poor? A valve is a mechanical device, if the electrode dimensions are the same then it must perform the same. Hence trying to find out why two physically different valves, long and short plate, should be the same.It becomes apparent that the real secret to valves is the cathode, its coating composition, activation etc.I have ended up with a selection of books, but have to say none are really nitty gritty detail books. The books do refer to lots of society etc papers so I wonder if all the real information is in them. Never seen any to check. Also the cathode must have been the manufacturer's trade secrets and wouldn't publish any real details in any case. I have also never found details of how you vary the electrode size, space etc to vary the valve characteristics. Sort of move the ECC81 grid 0.010" closer to the cathoide to get an ECC83.If anyone has any thoughts and knowledge it would be useful to put it down here.My booksFundamentals of Vacuum Tubes 2nd ed - EastmanTheory of Thermionic Vacuum Tubes - ChaffeeWireless Vacuum Tubes - Scott TaggartFundamentals of Electron Devices - SpangenbergPrinciples of Electron Tubes - ReichFundamentals of Vacuum Tubes - EastmanThermionic Vacuum Tubes - Van Der BijlTheory and Applications of Electron Tubes - ReichThe Oxide Coated Cathode - Wagener

author: Pjotr
author_rank: Frequent Contributor
timestamp: January 29, 2016, 11:29:26 am
content: As said before therearesome pretty good text books from the '30s - '50s area of the past age, that describe the theory and physics of the innards of vacuum electron tubes in depth. I found several at the library of Physical Faculty of the Technical University at Delft decades ago. But I have no titles at hand.A few years ago I went to there again to look up some of those books. But unfortunately that library was shut down and all those books went to the main university library. It seems they disappeared there in some black hole, completely unfindable...So, if someone has access to the library of MIT or Berkeley University etc. it would be nice to recover this kind of material and make it available on the web. It is historical material but nevertheless still valuable today.

author: uncle_bob
author_rank: Unknown
timestamp: January 29, 2016, 12:37:52 pm
content: HiThe last time they did a course on vacuum tube design in the US was in the early 1980's. Any material related to that is likely long gone. Even then, I believe there were only a few dozen "students" involved. Back then, the funding and focus was all from the government. There really was zero interest from industry. The best source for this stuff may be the various "scan and save" projects.Bob

author: chris_leyson
author_rank: Super Contributor
timestamp: January 29, 2016, 07:50:13 pm
content: Phew !! found it, Radiotron reprint,Front Cover saysCLASSIC EDITIONRadio Designer's HandbookFourth Edition 1953, Revised 1967F Langford-SmithNewnesISBN 0 7506 3635 1

author: uncle_bob
author_rank: Unknown
timestamp: January 30, 2016, 02:07:34 am
content: Quote from: chris_leyson on January 29, 2016, 07:50:13 pmHiI have a few versions of that sitting around here somewhere. It's useful for the "how to design with tubes" stuff. Not so useful for the "how to design a tube from scratch" part of it.Bob

author: TerraHertz
author_rank: Super Contributor
timestamp: January 30, 2016, 03:22:45 am
content: Some more possibly related books:Luminous tube lighting. Henry A Miller. Newnes 1945Applications of neon lamps and gas discharge tubes. Edward Bauman. Carlton Press 1966Vacuum tube electronics. Russel H Krackhardt. Charles E Merrill books. 1966Glow Lamp Manual. 2nd Ed. General Electric Co. 1966.Introduction to plasma physics. B.M.Smirnov. Mir Publishers. 1975Low energy electron collisions in gasses. Also L Gilardini. John Wiley. 1972Ionization and breakdown in gases. F Llewellyn-Jones. Methuen. 1957Vacuum as an insulator - An indexed bibliography. R Hawley & A Maitland. Chapmal & Hall. 1967Physics of weakly ionized gases. B..Smirnov. Mir publishers. 1981High frequency Thermionic Tubes. A.F.Harvey. Chapman & Hall. 1943Electron Tubes. Royce Gerald Kloeffler. John Wiley. 1966Electron devices & circuits. John M. Carroll. McGraw-Hill. 1962Fluorescent lighting manual. Charles L. Amick. McGraw-Hill. 1947Neon Signs and cold cathode lighting. Samuel C Miller. McGraw-Hill. 1952Charged particle beams. Stanley Humphries Jr. John Wiley. 1990 (print on demand)There's nothing like a book on electron tube theory or plasma physics, to rub in the woefully inadequate state of my maths ability.Just grabbed this:Gaseous Conductors : Theory and Engineering Applications by James D. Cobine (1941, Paperback)Condition: Good. Price: $24.89 + Shipping: $3.49Quote from: sarepairman2 on January 27, 2016, 03:45:28 amWarping space so that millions of them can fit in a few cubic millimeters?Since there's no way vacuum tubes will ever compete in the information processing field, that leaves fashion and physics.Ie valves are not coming back without some conceptual breakthrough in either of those areas.It's a pity you don't want to be more specific, you tease.But then, I can sympathize. My own project obsession also is somewhat valve-like (involves ions in partial vacuum), and I don't talk about details of that either.

author: calexanian
author_rank: Super Contributor
timestamp: January 30, 2016, 05:23:54 am
content: Here is the link to the article I wrote a while back.http://hackaday.com/2014/11/21/artisanal-vacuum-tubes-hackaday-shows-you-how/I wrote this to encourage people to begin experimenting with tubes. Start on the most basic level and work up. I got a call from a friend still in the tube business, and has been since the 60's and they in turn were contacted by a new company trying to make tubes and it is clear they are unwilling to really learn about what is required and just want to jump to the end prize without going through all the learning steps. Its like any other field of engineering. Crawl before your first step, and walk before you run.

author: sarepairman2
author_rank: Frequent Contributor
timestamp: February 07, 2016, 02:52:56 am
content: got gaseous conductors.

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 07, 2016, 09:09:07 am
content: I really do believe there are new applications of tubes in the physics and power area.Plasma physics is kinda big and it is impenetrable even to the best mathematical minds and supercomputers.Plasma and it's interaction with magnetic fields is kinda big deal today y'know. It is also the thing that gives us our most accurate clocks.

author: AF6LJ
author_rank: Unknown
timestamp: February 07, 2016, 01:33:36 pm
content: Quote from: calexanian on January 30, 2016, 05:23:54 amI read that article; I thought it was very good.

author: calexanian
author_rank: Super Contributor
timestamp: February 08, 2016, 05:18:04 am
content: Quote from: AF6LJ on February 07, 2016, 01:33:36 pmThank You. I am trying to come up with another article but am lacking in inspiration. Everything I have come up with is either to much of a liability or just not interesting enough.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 08, 2016, 05:42:50 am
content: Quote from: calexanian on February 08, 2016, 05:18:04 amThe biggest downside is the capital investment required to work with it:High vacuum system (at least a vane pump and diffusion pump), bell jar (for experiments)Glassworking torchesAssortment of glass rods, tubes, etc.Glass blowing experience(!)An assortment of unusual metals, for making glass seals, electrodes, etc.Spot welder (usually a small capacitive discharge type)Glass lathe preferredAnd that's just to reliably create demonstrations, mere novelties. To actually make something practical, requires even more: jigs and dies to form very precise parts; oxide cathode materials; support materials (usually mica or ceramic); etc.I would love to see what could be done with modern techniques, though. Add to the list: laser cutter, general 3D printer (probably one capable of cementing ceramic and metal powders), mill (including ceramic cutting bits), wire bonding, etc.Probably the fanciest thing that could be made today, would be a planar triode or tetrode, using a layered ceramic base, with metallization for placing the electrodes upon. The filament can be strung across an opening, or the cathode supported on fine springs over a heater. The grid can be laser cut, hopefully with a very low cross section; otherwise, perhaps a wire screen or mesh can be made without too much trouble. Subsequent grids can be mounted in the same way, supported on tiers of the ceramic base. A plate goes on top, perhaps brazed in place, in vacuuo, also sealing the assembly and providing a heatsink base.The trick for really good tubes (high Gm, low loss = high bandwidth) has always been, closer grid-cathode spacing and finer grid wires. Planar triodes got to about 10GHz in the 60s and 70s, though still with too much capacitance (a few pF) and too high of a load resistance (~kohms) to achieve more than a narrow bandwidth (like, 5GHz +/- a few percent).The "next big innovation" has always been cold field-emission cathodes, but I guess I don't see any reason they should work out; many things have been tried and they remain unreliable. You can't make a space charge, anyway, which is part of the charm of a proper vacuum tube (though not necessary).Even so, the load impedance limitation doesn't seem to have any obvious solution. The problem is current density, which is limited by the electron space charge. If you neutralized the charge with a bulk positive charge in the vacuum, well, by gum, you'd have a semiconductor with free conduction electrons (rather than free-as-in-vacuum electrons). Indeed, it's not at all wrong to call a tube a "vacuum FET". The simple fact that conduction electrons can be packed about 10^6 times more dense, despite also running 10^3 times slower (drift velocity in Si < ballistic velocity in vacuum), means transistors win by a long shot.Tim

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 08, 2016, 10:59:14 am
content: One of the interesting applications might be thermionics in space, where the vacuum is omnipresent.Also most of the experimental physics experiments today are glorified vacuum tubes.This for example is a Lithium beam accelerator.SourceHere is a THz Time Domain SpectrometerSourceSo in my opinion Vacuum and thermionics is still a current technology as long as we can find new fields to apply it to.

author: timb
author_rank: Super Contributor
timestamp: February 08, 2016, 11:13:07 am
content: Actually, they're experimenting with Vacuum Channel Transistors, which is sort of kind of almost like a Vacuum Tube. Only without the the tube. Oh yeah, and the filament. ...and plates. But it *does* have the vacuum, so that's like 50% of a Vacuum Tube, right?http://spectrum.ieee.org/semiconductors/devices/introducing-the-vacuum-transistor-a-device-made-of-nothing

author: calexanian
author_rank: Super Contributor
timestamp: February 08, 2016, 09:54:01 pm
content: Quote from: T3sl4co1l on February 08, 2016, 05:42:50 amAll true

author: calexanian
author_rank: Super Contributor
timestamp: February 08, 2016, 09:56:08 pm
content: Quote from: HAL-42b on February 08, 2016, 10:59:14 amSpace is actually full of a bunch of stuff. many many charged particles as well. You would find that you still need to have a sealed tube with a gettering material.

author: sarepairman2
author_rank: Frequent Contributor
timestamp: February 10, 2016, 04:09:37 am
content: i am going to need a bigger garagesurely the glass part can be outsourced to chemglass maker.and I bet some ease of manufacture can be made for prototyping tubes.It's not possible to make a reusable vacuum seal system? Like a vacuum tube breadboard with some connectors coming out of it?run it connected to a vacuum pump with a heated getter around the seal to keep air out?i don't see the need for making advanced ruggedized glassware for prototyping thermoionics.can you metalize a bell jar lip/embed metal in it/ then solder it to the bottom glass disk (which also has a metal disk or metalization) using a hot plate to make a gas tight seal? make the bell jar over sized so the metal ring does not interact with the system significantly.i think alot of the difficulty for making these things is that they have to work for 20 years etc etc. not a prototype you take measurements on for 20 minutes. I don't think you need to worry about baking out the impurities too much, as that is more of a life time thing then a device performance thing (like induction heating the entire assembly). or just make it tall and narrow so you can still do a bake outhell, i imagine running a test for 10 seconds is enough to say alot about the functioning of a theoretical design. let materials engineers (zzzz) worry about longevity. roy batty that shit

author: calexanian
author_rank: Super Contributor
timestamp: February 10, 2016, 05:10:13 am
content: How large is this setup going to be? generally laboratory setups are made of demountable components including electrical feed troughs. Duniway Stockroom corp is the company I use for lab type parts for vacuum systems. Kurt J. Lesker is another company that comes to mind. There are several others out there as well. Order up one of their catalogs and thumb through. Lots of good info in them.

author: sarepairman2
author_rank: Frequent Contributor
timestamp: February 10, 2016, 05:14:53 am
content: I can't imagine what one of those physics packages costsmaybe you could make my idea using a salad bowl and a blow torch thoughand i have no idea i got over whelmed with books in this thread, actually having some kind of cheap thing that i could experiment with would probobly actually get me to follow through with this idea some what. I am not very good at doing theoretical things that are not followed up by a good chunk of actual tactile interaction/etc, it is just not fun.how do you bake out a thermoionic prototype that is inside one of those flanges that the companies you mentioned sell? a robotic arm seems like it would off gas really bad.

author: uncle_bob
author_rank: Unknown
timestamp: February 10, 2016, 12:17:41 pm
content: Quote from: sarepairman2 on February 10, 2016, 05:14:53 amHiWell not that the cost has come up ..... if you are doing this with major government funding, you shop the surplus market. It's not the many billions a modern semiconductor line costs. It's still way more than you can afford as a normal person. (No, Bill Gates is not a normal person in this respect).Bob

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 10, 2016, 02:32:00 pm
content: Just use a TIG welder and stainless steel plumbing.Just like in the second picture I posted, a big thick walled pot with an o-ring for seal and a slab of metal for a lid. Use spark plugs as electrical feed-troughs and so on.For vacuum you can get away with a mechanical pump + an ion pump. It will be slow but nowhere near as expensive as a turbomolecular pump.

author: uncle_bob
author_rank: Unknown
timestamp: February 10, 2016, 06:01:54 pm
content: Quote from: HAL-42b on February 10, 2016, 02:32:00 pmHiYou probably will need a cold trap in that setup as well unless you really like buying new ion pumps all the time.....Bob

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 10, 2016, 07:27:01 pm
content: Quote from: uncle_bob on February 10, 2016, 06:01:54 pmWouldn't the mechanical pump evacuate enough moisture for that to not be a problem?

author: uncle_bob
author_rank: Unknown
timestamp: February 10, 2016, 10:57:37 pm
content: Quote from: HAL-42b on February 10, 2016, 07:27:01 pmHiYou get an oil back stream from a mechanical pump. If you are trying to pump down further with a ion pump, it will poison the poor thing pretty quickly. The cold trap takes out the oil.Bob

author: AF6LJ
author_rank: Unknown
timestamp: February 11, 2016, 01:02:44 am
content: Quote from: uncle_bob on February 10, 2016, 10:57:37 pmI wouldn't use an ion pump, an oil diffusion pump, and a cold trap is better.

author: uncle_bob
author_rank: Unknown
timestamp: February 11, 2016, 02:21:40 am
content: Quote from: AF6LJ on February 11, 2016, 01:02:44 amHiI would not go as far as an ion pump either in this case. However IF you do and IF you use an oil pump, you need the cold trap. IF you have the cold trap, by definition you need a way to chill it. Pretty easy if you have a liquid nitrogen tank out back. Not quite as easy if you don't.If you are starting from scratch and have to put in all the infrastructure, there is a bit to it. This is still assuming you need ion pump levels. You probably are better off with a (working, known good, don't send it in for repair) turbo pump on a one off system.Bob

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 11, 2016, 02:48:29 am
content: A Stirling Engine working in reverse could liquefy air. Just like in those old Philips videos.Mechanically this seems like the simplest contraption that can go that low in temperature. This might have been useful as a cold trap, only if it was available commercially.

author: calexanian
author_rank: Super Contributor
timestamp: February 11, 2016, 04:27:53 am
content: All of this is determined by what kind of experiments you wish to run. Some things (but not too many) are intolerant of any oils, back streaming, etc. For thermionic experiments oil rotary vane pumps and diffusion pumps generally are the best. For surface physics experiments you gotta go for the gold with turbo pumps and then ion or titanium sublimation pumps right near the volume being evacuated. Cryopumps are also a good thing. Just depends.

author: Cyberdragon
author_rank: Super Contributor
timestamp: February 11, 2016, 04:30:42 am
content: You have attracted the attention of a fellow tube head. It seems as though this thread has gone off topic a bit. Allow me to drop my collection of textbooks on it to fix it.Electronic Circuits, E.J. AngeloRadio Engineering, Frederick E. Terman, third editionElectronic and Radio Engineering, Frederick E. Terman, fourth edition (both U.S. and international editions)Radio Engineers' Handbook, TermanIntroductory Electronics for Scientists and Engineers, Robert E. Simpson (covers from tubes up to digital logic)

author: uncle_bob
author_rank: Unknown
timestamp: February 11, 2016, 12:08:09 pm
content: Quote from: Cyberdragon on February 11, 2016, 04:30:42 amHiThe interest seems to be in designing a vacuum tube it's self rather than designing a circuit that uses a tube. It is still unclear (at least to me) what sort of tube we are trying to come up with design textbooks for. The original question *could* have been about how to do a scratch design of a magnetron or a traveling wave tube....(we haven't covered that end of things yet).Bob