Hi, I had a quck try at this. Hooked up a standard 5mm white LED to a photodiode amplifier and 'scope. It showed good response to light as expected. I packaged...
Two things yet to try, I'd think: First, a 3W or 4W power-LED, with a phosphor "brick" over the junction (as opposed to the "coating" sprayed onto the 30-80ma...
Hi Robert: It may be that one of the high brightness white LEDs (1 to 5 watt) would behave differently than the 3 mm or 5 mm 20 ma round ones. Have Fun, Brooke...
Hi, that's next on the list of things to do. I've got some Lumileds 3 w units to try. The 5W ones won't help as they are just 4 chipw in series/parallel....
... behave ... I didn't mention the 5W variety for a reason, but now I'm thinking it may have been a mistake. The 5W, due to their unique construction, *may*...
Hi Ron: I've been looking into astronomical application of photo diodes and have found there are two general ways they can be used. 1) Like a solar cell where...
My PM1703M's ( now being sold on eBay) use a CSI(Tl) crystal on some sort of photocell and are remarkably sensitive. So far no luck getting a schematic or any...
... from ... CdS ... dark ... not ... acting? Dunno, but can SWAG that it's short persistence. We have three white LED flashlights. One has a cluster of...
Selling by the square inch, so any project can now have a custom cut crystal. Detects Alpha-Beta, Gamma, X-Rays, even neutrons! Scintillator crystal Radiation...
I had to use the video camera, All the leaded glass gave me some auto focus problems in the begining. A density experiment, The whole screen is covered with...
Any Tachyon, Strangelet or Nuetrino Scintillation Material? Chris Cavanaugh cav427@... Yukon, OK ... From: fucian@... To: CDV700CLUB@yahoogroups.com ...
Hi Brooke I have designed photodiode amplifiers as part of my "day job" .As you say they can be used in photovotaic or current mode. The amplifier I was using...
Hello Everyone! I'm new to this hobby, and very excited to have found this community. I've already done a lot of reading, and for my first geiger counter, I...
My first question: I know some of the capacitors are quite old. Is a minor overhaul recommended before sending it for a calibration? Hi Ron! Welcome aboard!...
Almost all major cities have calibration labs that service hospitals, etc. for calibration purposes. Almost all such labs will use Cesium for the calibration...
Hi, Give Allyn Goshy a try at Allnilo@... His web site is at http://members.aol.com/allnilo/index.htm He does calibration, repair and modifications at very...
Can one add the X1000 capability without the need of recalibration? I am pretty good at electrical work (electrical engineering major here). And as I see it,...
... am ... And as I see ... is ... Good question Matt! Can anyone answer these questions for us? As it regards my question in the first post "What are the top...
Yes and no! If everything in the circuit were independent of count rate effects, an extension of the meter scale in cpm would be easily accomplished by an...
That said, the count rate at 100x, max scale is 30,000 cpm. Looking at the LND 720 tube, the closest modern equal to the 6993, it stays quite linear up to...
... count ... easily ... tubes ... short ... This ... the ... factor ... meaningful ... recalibration? Since LND 720 mentioned by another member here is a...
... tube ... highest ... The LND 720 is physically the same size, same connector and same sensitive area as the original tube. I think it's actually slightly ...
The LND 720 and QPL 6993 are for all practical purposes the same. To count *higher* radiation fields more accurately, the normal procedure is to simply use a...
I think many of us may be confused because people commonly state they have samples measuring over 60kcpm on a CDV700, but do not list the probe type (or ...
First off, Thank You! Geo for those links to the HomeRadLab. I am gobbling up the articles at a furious rate. And as a demonstration, I've read your article...
Basically if a tube is known good, and displays no odd characteristics, the tolerance is probably pretty close to the design goals. After all, it is the fill...
Saw U.N. on PBS "Wired Science" this week. It may show in your areas this week, so keep an eye for the program on "Wired Science." Interesting to see Bob...
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