If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #50
Joined: Thu Feb 09 2006, 04:07AM
Location: Vernon, B.C, Canada
Posts: 324
Chris *ChristopherRobin, or anyone that can answer this...What is a good geiger counter for, say, prospecting for radioactive minerals? I noticed the one Chris has in his picture is an old fallout survey model, but I keep reading that those are only good for really high levels of gamma radiation...I'm sort of looking for an ebay buy... Any suggestions are welcome aslong as they don't have me spending $250 on a geiger counter....
Registered Member #193
Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022
Actually low level “safe†exposure levels don’t exist – only considered acceptably low probability of developing complications. The jury is still out on the threat from low level radiation. Have a look at this
Registered Member #65
Joined: Thu Feb 09 2006, 06:43AM
Location:
Posts: 1155
The 32.768KHz tuning fork cut crystals traditionally have predictable performance and aging characteristics. However on new PLDs, a contingent RC or LC clock source tied into the frequency multiplier and PLL combo based oscillators provide a crude failsafe (even if its fairly inaccurate +- 5% -> 15%.)
Anyone seen the Mercury Aluminum clock that’s more precise than the Cesium based units?
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
Carbon_Rod are you talking about the Therac-25 disaster? If you are, then the cause of it was something totally different to what you said. It was just plain old bugs in the software that controlled the thing. It's still a classic lesson that everyone wanting to write embedded software ends up studying at one time or another.
Somehow I get bad feelings when I read about kids crushing up radioactive rocks to see them glow. >_< I guess it can't be that bad though, if you worked in a uranium mine you would see plenty worse radioactive dust.
Registered Member #65
Joined: Thu Feb 09 2006, 06:43AM
Location:
Posts: 1155
A rather interesting classic problem -- and somewhat like the machine operators touch screen units input errors made without looking at the screen. But, IIRC it was not the same incident as it was unrelated to interface or coding problems. Timer crystals do naturally change over time, and usually good software will compensate with a predicted error estimate based on the manufacturing lot date and temperature.
Handling any kind of accumulative hazardous substance for extended periods is never a good idea – just ask Curie. Not something you would want in your home.
Registered Member #99
Joined: Thu Feb 09 2006, 06:10PM
Location: florida, usa
Posts: 637
Well, i got my autunite in the mail...Really pretty under a blacklight! As for the spintharascope, I have order zinc sulfide (silver activated). I also got a 8g piece of thorianite on ebay...This should work good, no? I read that thorium is a good alpha emitter...
If not, where could I get a piece of Kasolite?How much would this cost? Matt
Registered Member #99
Joined: Thu Feb 09 2006, 06:10PM
Location: florida, usa
Posts: 637
Christopher Robin wrote ...
A CDV-700 Geiger with mr/hr is a good cheap counter you can get on ebay. What you need to watch out for is the CDV-715 with r/hr reading. The CDV-715 is not sensitive for prospecting as if you are reading r/hr you are cooked! Both can be bought on ebay. There also are little speaker units that can be connected to side of unit so you do not need headsets; Also on ebay.
CDV-715 is on the left and CDV-700 (the one reading in mr/hr) is on the right.
Again, ensure you use precaution when handling hot rock, do not bring in house, do not eat or smoke when handling and wash hands after touching hot rock. Try not to handler much as radiation exposure is accumulative!
rgs, Ch_r
Edit: thorium is excellent alpha emitter and presents a radiation hazard however, so ensure you handle safely. I traded someone in town for my sample of Kasolite; however, it is on a few rock sites and ebay once in a while.
Some updates... I made a very weak spinthariscope!I dont know if it was weak due to the autunite just being a bad choice or, because I used a glow in the dark star
After some fussing with it, and the lens, I began to see what i thought were sprakles...Every now and then it proved it wasnt just me ...Weird...While the phophorescent paint glows green, the sparks are all blue! I tried with phosphor from a broken flouresncent lamp(i actually pulled ity out of the socket in my kitchen and busted it under and old comforter i didnt want anymore...) Not even a HINT of activity...
Now i cannot wait to get my silver activated zinc sulfide from united nuclear, as well as my thorianite pebble from ebay to see just how much better it all works! United Nuclear mentions their spinthariscopes use high grade thorium ore. How does one know what is high grade or not by looking at it?My pebble looks to be quite dark, almost like pitcheblend, but is infact thorianite...Afew specs, they say, of this ore is all it takes to get their phosphor going... I will keep everyone up to date, and take some pics of my "stuff" shortly...
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
Things to do with "hot rocks"
Any suggestions are welcome aslong as they don't have me spending $250 on a geiger counter....
...Weird...While the phophorescent paint glows green, the sparks are all blue! I tried with phosphor from a broken flouresncent lamp(i actually pulled ity out of the socket in my kitchen and busted it 