sc_pic, new PIC project with high voltage ;-)

Are you going to do pulse-height analysis? If you do, you can get energy spectra, although you have to be more careful about the optics, and scintillators have mediocre PHA resolution. Still, it could be fun.

series

Seriously, get some blue-grid vellum, and electric eraser, and an electric pencil sharpener.

ftp://jjlarkin.lmi.net/Auto.jpg

John

I have forwarded this jpg to the FBI, NASA and the NSA for processing,

to produce a high contrast ratio image, for lurkers on sed. ;-) MikeK

Can Panteltje really patent that mouse turd hidden under the eraser ?:-) ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
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I love to cook with wine.     Sometimes I even put it in the food.

g,

Why not? it's a high energy ego generator.

On a sunny day (Sat, 4 Dec 2010 12:12:37 -0600) it happened "amdx" wrote in :

If you use Linux you should view it with xv -nolimit test_diagram_img_2473.jpg The original is 3072x2304, 24 bit, and every detail is clearly readable, even for me at my age, without special glasses on a normal LCD monitor.

NASA, shuttle launch postponed again, I think they just do that to stay in their jobs (all over after this one).

NSA??? LOL Few weeks ago one said: 'put him on the watch list', See how secret they work?

They cannot even get wikileaks offline, the whole thing is now on

and 100% reachable this morning. If you have torrent you can download the whole thing, but it may well be faked...

FBI? I dunno about that, but I have seen some funny Hollywood movie about 2 guys that were FBI agents, and investigated a priest .. don't remember the name. They may be the best of the of lot (FBI).

So that was the off topic part.

On a sunny day (Sat, 04 Dec 2010 11:23:07 -0700) it happened Jim Thompson wrote in :

Jim, for money you can patent anything, its 5000 Euro now for Europe IIRC.

On a sunny day (Sat, 4 Dec 2010 10:30:31 -0800 (PST)) it happened linnix wrote in :

You are just jealous because you have nothing to show here.

On a sunny day (Sat, 04 Dec 2010 14:24:04 GMT) it happened Jan Panteltje wrote in :

series

Wow, 29 mA at 12V DC for the whole thing, with 1250 V DC output. Will be a bit higher with the PMT connected... Think I broke an efficiency record :-)

Just pullin your leg, havin some fun with ya Jan, I've never used a PIC, but I always like to see your projects. Thanks, MikeK

On a sunny day (Sun, 05 Dec 2010 07:29:47 -0800) it happened life imitates life wrote in :

Works here.

missile?

I do not see that, the PMT is sensitive over a large area, not like a camera with a lens. Tell me more, so I can:

missile?

with a lens.

Here is my version. It is meant to fit onto the back of a socket though. The holes keep leakage from occurring, and the standing resistors do as well. The PCB is without mask, which also helps. It should all also get potted.

The HV board sits over that and the shield, and it all fits into a small can a couple inches long.

I can post the HV part too, but you would have to discern the schematic from that. It is too easy as it only has a few components to make a clean 1500V. Wouldn't take much to make that 1800V.

You should only generate and use the amount of HV you need, not try to quell an device that is overkill for the task.

On a sunny day (Sun, 05 Dec 2010 08:44:10 -0800) it happened life imitates life wrote in :

Yes, the holes is a good idea. I did consider, and still may, put this whole thing in a piece of plastic rain pipe, 60mm diameter on the inside. It would have to be treated to not let any light through. I cannot mount it in metal, as it needs to detect low energy alphas too. I am running at 1250V, the PMT has a max spec of 1700 V. While I was looking for 'light proof foil' I came across this site, in Amsterdam:

Look what they are selling :-)

pipe, 60mm diameter on the inside.

Amsterdam:

If I need to update my grow room, I'll consider them, since they have been doing it for a long time.

pipe, 60mm diameter on the inside.

Amsterdam:

Here is one of my earliest circuits.

Very heavily characterized, and proven. It doesn't get any better than this for a cheap, regulated HV source.

Free engineering, unleashed upon the world.

500V to 1500V adjustable. Very hardy too, as long as the current limit resistor is carbon comp type. The "embedded cap" is a strip of cladding on an internal layer to the ground plane. IIRC, that strip is like .25" x .8". But that would have to be experimented with, and can be fashioned by other means. It is for the feed forward on the feeback loop.

It is better than your eraser covered thingy, I am sure.

You are welcome to use it, and yes, John, Math was involved when I designed it.

E-sized or larger white board then CAD has been the way for years now.

Especially when a group of engineers is involved.

series

Doubtful.

How low can you take the V and have it still operate (loaded)?

That is the real test.

You should take some nice, small diameter coax like rg-179 or such, and make a nice HV capacitive load for it. You can look up the pF per foot of most coax, and the dielectric on rg-179 is like 2kV (might want to choose a slightly bigger coax).

You dress the shield an inch or so back from the end, and seal the end of the center conductor, then seal all of that in some HV shrink.

So, if you had 10pF per foot coax, and you made a 14 inch piece of it, and dressed it as stated, you would have a 13pF "Capacitive HV Load Device".

On a sunny day (Sun, 05 Dec 2010 11:54:00 -0800) it happened life imitates life wrote in :

Maybe you could not see the picture of the HV cascade, ftp://panteltje.com/pub/sc_pic/sc_pic_hv_cascade_sense_resistors_img_2455.jpg it has a nice capacitor to ground in it. There is also a 2kV ceramic to ground locally at the PMT. Since I am looking at impulses there is just a low average load, and the HV is stabilised via the sense resistor chain for longer durations.

On a sunny day (Sun, 05 Dec 2010 11:26:17 -0800) it happened life imitates life wrote in :

Mine has RS232 input, voltage can be set via RS232 from 0 to 1305 V in 16 steps for this configuration. You can read the voltage directly via RS232, and my circuit is simpler, uses only 2 chips, one for the RS232 and one PIC for the PWM generation. The PIC also does a lot of other things, see: ftp://panteltje.com/pub/sc_pic/ ftp://panteltje.com/pub/sc_pic/test_diagram_img_2473.jpg If you have problems accessing the site and a fixed IP address, let me know your IP address, maybe the security script firewalled it for some reason.

? Is he here too?

On a sunny day (Sun, 05 Dec 2010 11:43:17 -0800) it happened life imitates life wrote in :

Your diagram is hardly readable blue on black is low contrast and the green on black sucks too. Red sucks too on black. Perceived brightness: Black = 0 green = 59% red = 30% blue = 11% white = 100% For a decent contrast use black on white, or yellow (green +red = 89%) on black. Or blue on white, basic colormetry seems alien to some people here.