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 #33
Joined: Sat Feb 04 2006, 01:31PM
Location: Norway
Posts: 971
Grenadier wrote ...
This leads me to believe that it can't supply more than 1ma. But i'm not sure. The mA's could easily be much higher, the voltage lower on the secondary
And with a lower voltage and a higher current, the radiation dose would be much lower. For any given power, the combination with the highest voltage will always make the largest amount of radiation.
Registered Member #2893
Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242
Nah, i decided i'm done with this. It's caused me too much trouble. Hopefully i can sell the tube.
I'm starting to think about this again, however i still need to make $125.
What is a better ballast idea? I'm stumped.
edit; just tested it with a 120 ohm resistor, transformer draws 1a short circuit, so 1.2ma secondary minimum. Problem is i don't know the voltage. It could very well be 30ma at a low voltage, and that could easily fry the tube...
If i can scrounge up $125, the project is back on, otherwise it's a dud. (the tube's not selling anyway)
edit 2; i'm gonna go for it. I want to be the youngest person to make a fully functional coolidge x-ray machine. that'll look good on a resume. I still need your input on the transformer current/voltage, and what you predict what will happen. Plus i still need $125. If you want to buy anything i listed, (cept the tube), go for it!
I bit the bullet and bought the sheet. Maybe when this is done i can radiograph people's stuff for $8
Registered Member #33
Joined: Sat Feb 04 2006, 01:31PM
Location: Norway
Posts: 971
Grenadier wrote ...
Nah, i decided i'm done with this. It's caused me too much trouble. Hopefully i can sell the tube.
I'm starting to think about this again, however i still need to make $125.
What is a better ballast idea? I'm stumped.
edit; just tested it with a 120 ohm resistor, transformer draws 1a short circuit, so 1.2ma secondary minimum. Problem is i don't know the voltage. It could very well be 30ma at a low voltage, and that could easily fry the tube...
If i can scrounge up $125, the project is back on, otherwise it's a dud. (the tube's not selling anyway)
edit 2; i'm gonna go for it. I want to be the youngest person to make a fully functional coolidge x-ray machine. that'll look good on a resume. I still need your input on the transformer current/voltage, and what you predict what will happen. Plus i still need $125. If you want to buy anything i listed, (cept the tube), go for it!
I bit the bullet and bought the sheet. Maybe when this is done i can radiograph people's stuff for $8
Final schematic revision.
[Edit: Try not to triple post]
A high current through the tube won't necessarily kill it, it's high current in combination with high voltage thas will kill it, high power in other words. A high current through the transformer secondary is very likely to kill the transformer though. For this reason I would absolutely put a current meter on the secondary side.
I would also place the SSR after the variac. Variacs usually draw a very large current surge at startup, even small ones. Having the SSR switch this current every time you want to do an exposure is not a good idea. It's even worse if the SSR is a zero-crossing one, as the worst possible time to turn a transformer on is at the zero crossing. If you have the SSR after the variac, there is an other advantage too, you can read the actual output voltage of the variac before you press the exposure switch. I would also not put the ampere-meter before the variac, as the surge startup current might kill it.
Regarding the ballast resistor, I don't really like that idea, as it's definitely going to make the whole thing harder to control.
There's also no decoupling capacitors on your AVR. I'm sure you just forgot to draw it, just thought I'd mention it because I've had lots of trouble when trying to drive HD44780-based LCDs without enough decoupling capacitance on the microcontroller, these LCDs seem very sensitive to noise on the power and data lines.
Registered Member #2893
Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242
I feel I never gave a very good reason for abandoning this project. Well here it is.
I did end up getting this working, but the day after I fell very ill. I attributed it to radiation. I ended up going to quite a few doctors and they couldn't figure out what was wrong. It wasn't until I sold the transformer on fusor that I found out it was just a superbug. Don't remember what it was exactly, but it ruined the project nonetheless. I also destroyed my lead box because it was starting to get stress cracks.
Well now that I'm seeing what Freitsu is doing with the tube I sent him, I got the x-ray itch again. In a few months I plan on buying another x-ray head. (well I'll need someone else to get it, I'm banned from egay).
I plan on putting a lot less work into it this time. This project was too hard to be any fun; it got boring. I have 10sqft of 1mm lead sheet left, so I'm just going to wrap the head in it. I'll build a nice wooden box to hold it in too. At night I'll set it up in my backyard, aperture facing the woods. Then I'll just set up the photograph.
Exposure time will be controlled by me plugging it into my basement outlet via a 100ft extension cord; completely idiot proof and fail safe. Not too many rays are going to get me through the 1" aluminum head + lead ceramic tube covering + 3mm lead + 20 ft packed dirt + cinder block wall.
Edit: Awesome. Atlasfrontiers, the guys I bought the SS.White from no longer sell through ebay. They accept credit cards. :D
Edit2: Wow, they have quite a selection! $95 heads!
Registered Member #3147
Joined: Sun Aug 29 2010, 10:53AM
Location: Finland
Posts: 56
Great to hear you're getting back to this rewarding hobby, Grenadier!
A slight highjack:
This is maybe not the best place to introduce myself but I'll go ahead anyway since I don't find a "Welcome section". I'm a 28 y/o guy from Finland that likes to "mess" around with h/v and in the last few months x-rays caught my interest so I thought that I would read whatever information I could find online about the subject.
I started to generate x-rays with the 6VS-1 shunt stabiliser that when driven to produce x-rays is an avesome little tube with really tiny focalspot! Well then, moving on. At last I wanted to try out a real x-ray tube, and somehow I found my way to this forum and read/searched around and then found Grenadiers sale/trade thread, we agreed to make a trade and finally I got my long awaited tube!
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
Freitsu wrote ...
Great to hear you're getting back to this rewarding hobby, Grenadier!
A slight highjack:
This is maybe not the best place to introduce myself but I'll go ahead anyway since I don't find a "Welcome section". I'm a 28 y/o guy from Finland that likes to "mess" around with h/v and in the last few months x-rays caught my interest so I thought that I would read whatever information I could find online about the subject.
I started to generate x-rays with the 6VS-1 shunt stabiliser that when driven to produce x-rays is an avesome little tube with really tiny focalspot! Well then, moving on. At last I wanted to try out a real x-ray tube, and somehow I found my way to this forum and read/searched around and then found Grenadiers sale/trade thread, we agreed to make a trade and finally I got my long awaited tube!
Welcome Freitsu!
You will find we have about six other enthusiasts here, with one or two who never think about anything else!
Registered Member #3147
Joined: Sun Aug 29 2010, 10:53AM
Location: Finland
Posts: 56
Proud Mary wrote ...
Welcome Freitsu!
You will find we have about six other enthusiasts here, with one or two who never think about anything else!
Thanks!
I think you can count me in that group that never think about anything else! (well except maybe for some sideprojects, currently it's a scopeclock project) ;)
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
Freitsu wrote ...
Proud Mary wrote ...
Welcome Freitsu!
You will find we have about six other enthusiasts here, with one or two who never think about anything else!
Thanks!
I think you can count me in that group that never think about anything else! (well except maybe for some sideprojects, currently it's a scopeclock project) ;)
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.
Grenadier's big thread of Röntgen related shenanigans
