Coming goodies & request thread

This is for products and services from Joe Jarski and Doug Coulter. We've noticed others having trouble on some things, and think we can make a positive contribution to the community by making some of those things available to all at nominal pricing, so people can just get on with their own work.
Here is where these things will be described and sold.
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This is for Joe and Doug to display our joint projects for sale, and for questions and answers about them.

Coming goodies & request thread

Postby Doug Coulter » Tue Sep 20, 2011 5:59 pm

We have a list of stuff we'd like to make (and make available). This is being driven by our own needs, but if other people want to chime in and add requests, this is the place.

roman numeral A: MCA for NaI heads.

1. Tiny audio amp, lm386 based. This is for adding to various sensors for audio monitoring. I want to do this with a 386 because they aren't power hogs and will run down to 4 volts. The idea is to make it so small it's easy to add it to other things along with say, a headphone speaker. Most amp modules or chips need at least 10-12 volts to work, but for this sort of thing we don't need the output power - and don't want it to need a lotta input power either.

2. Regulated HV supplies for phototubes and proportional tubes. It will take two designs to cover both polarities, and we'll use our well established CCFL/fast diode/cap for the main show, but close the regulation loop around the HV instead of feedforward so you can run those two tube types that are quite picky about their voltage - both change gain a lot with small changes in HV supply, and in the case of phototubes, draw a lot of power, which is variable depending on what they are seeing - they really require pretty tight regulation to perform well.

3. Preamps optimized for the various sensor types. There's a world of difference between what comes out of a proportional tube and what comes out of a phototube with a fast scintillator -- about a thousand to one difference in pulse widths for starters, and the phototube stuff wants very good linearity for doing spectroscopy.

4. The PIC board we're using in the standard counter. These are field programmable in-circuit if you get a programmer, and those are cheap. Compilers for C are not so cheap, but if you like you can use the free assembly language from Microchip to program your own stuff. This is a nice little board, just add 5v and code -- all the fiddly stuff is done and working correctly. The board has USB, as well as RS-232 already done.

5. A tiny smd board that takes .8 to 4.9v and returns 5v regulated, efficiently. This is ltc 3400 based, and draws very little power when unloaded. I've used the design successfully in body-worn prosthetics. It will run on a single cell, up to three normal alkalines, or one lithium. More batteries make for more output current possible and longer life, but that's up to the user. The board will be so small it's almost a lump in the wire from the batteries to your project (it was under 1/4 of the 2" square board for the prosthetic - call it 3/4" square more or less).

6. Neutron detectors - we have several projects underway here, and we'll pick the ones that work best that we can make more of (and don't cost too much), and offer them. We're still in the selection process here, so pipe up if you have input to that. We're looking at NOS russian tubes (nice, not too expensive but limited in supply), hornyak (on my bench now), and large area recoil gas-proportional (needs no moderator, and might be both better and cheaper than a hornyak). We might also try a home made B10 tube, since it looks fairly easy with our capabilities.

7. Anything people want us to make -- if there's enough interest to get our costs paid off, that's the rule (and, our costs are low).

Any of this can be done as a "board and bag of parts" like Don Lancaster/SWTPC, or built and tested - your choice, and the price will of course be cheaper to you the less we have to do.
Let us know what is holding you back from getting your experiments done - we might have a good answer for you.

We're not really in this for the money at this point, more to just get one for ourselves, but done really right, not some one-off bench kludge -- we're hoping there's enough interest to justify doing things right, rather than quick and dirty. If it works, we all get better gear, and cheaper -- another benefit is direct access to the principal designers if things go wrong. Try that with a large instrument maker!
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Doug Coulter
 
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