X-Rays and High Voltage Hack Chat

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Hack Chat Transcript, Part 3
Lutetium • 02/21/2019 at 16:30 • 0 comments

Fran PiernasFeb-20 12:51 PM
that should work too, however I think that kerosene has shorter chains than mineal oil, so it's more likkely to burn than minearl oil

JarrettFeb-20 12:51 PM
kerosene does burn, yeah

guido.giunchiFeb-20 12:51 PM
How do you measure HV?

JarrettFeb-20 12:52 PM
it's one of the more commonly used EDM dialectrics though, so it's not instant death or anything

Fran PiernasFeb-20 12:52 PM
@guido.giunchi I do an indirect measurement:

Fran PiernasFeb-20 12:52 PM

https://www.youtube.com/watch?v=ZnGXrOs88dE

YOUTUBE MILLITESLA

JarrettFeb-20 12:52 PM
trying to remember why I wanted to use it instead of mineral oil (which is also used)

Fran PiernasFeb-20 12:52 PM
I know what I have at primary because I can measure it with the oscilloscope

Fran PiernasFeb-20 12:53 PM
(I have 138V) and I know then exactly the voltage on secondary because I know the turn ratio

Fran PiernasFeb-20 12:54 PM
btw that's the transformer the machine uses

Fran PiernasFeb-20 12:54 PM
around 5kV on secondary

guido.giunchiFeb-20 12:55 PM
What about DC? You can use a huge resisitive divider, but that scares me if the ground disconnects or opens

Fran PiernasFeb-20 12:55 PM
@guido.giunchi i don't trust resistive dividers when I have to measure 70 000V xD

guido.giunchiFeb-20 12:56 PM
Yeah, I was referring to that!

Fran PiernasFeb-20 12:56 PM
I use the oscilloscope to measure the low voltage part of the circuit and do some maths

Fran PiernasFeb-20 12:56 PM
Also, simulations are helpful

Fran PiernasFeb-20 12:56 PM
I used OrCAD to simulate all the circuit

vincent stuchlyFeb-20 12:56 PM
what about to measure lenght of the gab which the spark can jump? XD

Fran PiernasFeb-20 12:57 PM
@vincent stuchly you mean like this? :

Fran PiernasFeb-20 12:57 PM

Fran PiernasFeb-20 12:57 PM
Go and approach a ruler to it, if you dare

Fran PiernasFeb-20 12:57 PM
(I took that picture with the marx generator)

guido.giunchiFeb-20 12:58 PM
If I'm asking too much questions I'll stop, but I'm a curious electronics engineering student..

Why does the oil jump under HV?

Fran PiernasFeb-20 12:58 PM
(also it's my profile picture :D)

vincent stuchlyFeb-20 12:58 PM
I know :D it wasnt meant serious I am sorry

Fran PiernasFeb-20 12:58 PM
@guido.giunchi ask anything you want, I will answer like if @Dan Maloney if paying me for that

Fran PiernasFeb-20 12:59 PM
@guido.giunchi the oil gets ionized, not by the multipler, but by the air

Fran PiernasFeb-20 12:59 PM
I mean, that does not happen in the sealed box

guido.giunchiFeb-20 1:00 PM
Doesn't it move inside the box?

Fran PiernasFeb-20 1:00 PM
Yes, it moves a bit

Fran PiernasFeb-20 1:00 PM
but there is no air (almost) in there

Dan MaloneyFeb-20 1:00 PM
Looks like our time is almost up, but everyone is free to continue chatting as long as Fran wants to hang around, of course. I want to thank Fran for his time today and a really informative Hack Chat, and thanks to everyone for the great questions.

I also want to let everyone know that next week we'll be talking to Simon Jansen about "All Things Engima" - https://hackaday.io/event/163974-all-things-engima-hack-chat. Be sure to stop by.

Fran PiernasFeb-20 1:00 PM
so nothing happens

neil k. sheridanFeb-20 1:01 PM
Can we hear about the CT scanner before we finish!!

Fran PiernasFeb-20 1:01 PM
I will stay :P

Fran PiernasFeb-20 1:01 PM
Yes, I prepared some things to show

neil k. sheridanFeb-20 1:01 PM
:-)

Fran PiernasFeb-20 1:01 PM

https://www.youtube.com/watch?v=VqcW84oigto

YOUTUBE MILLITESLA

Fran PiernasFeb-20 1:01 PM
This is part of the live fluoroscopy before I did the scanner

Fran PiernasFeb-20 1:02 PM
I wanted to know if the camera could record it

guido.giunchiFeb-20 1:02 PM
The white dots are just high energy photons hitting the cmos sensor?
... Read more »
Hack Chat Transcript, Part 2
Lutetium • 02/21/2019 at 16:29 • 0 comments

guido.giunchiFeb-20 12:21 PM
I'm in Italy btw

Fran PiernasFeb-20 12:21 PM
@guido.giunchi if I don't find something on ebay I usually look for it on aliexpress

Fran PiernasFeb-20 12:22 PM
If you guys don't have a microwave transformer, another experiment you can do is a Marx generator

Fran PiernasFeb-20 12:22 PM
pretty amazing too

Fran PiernasFeb-20 12:22 PM

https://www.youtube.com/watch?v=oVXp3OkraMc

YOUTUBE MILLITESLA

Dan MaloneyFeb-20 12:22 PM
@Fran Piernas - is that where you sourced your dental X-ray tube?

vincent stuchlyFeb-20 12:23 PM
the one wire of output side of MOT is connected to the core and if you touch it you die, what about to built some insulating box for it?

Fran PiernasFeb-20 12:23 PM
I bought it on ebay, I was extremely lucky to find it new from a US seller

Nevermore78 joined the room.Feb-20 12:23 PM

Fran PiernasFeb-20 12:23 PM
@vincent stuchly you can do it, however if you care about not touching it you are safe

[skaarj]Feb-20 12:23 PM
Hey @Sophi Kravitz

neil k. sheridanFeb-20 12:24 PM
I would have x-rayed my hand!

Fran PiernasFeb-20 12:24 PM
MOTs are "low" voltage, just 2kV

[skaarj]Feb-20 12:24 PM
Got something for you

Nevermore78Feb-20 12:24 PM
Hi everyone!

Fran PiernasFeb-20 12:24 PM
@Nevermore78 Hi partner!

[skaarj]Feb-20 12:25 PM
hmmm you're not near your terminal, better PM

Fran PiernasFeb-20 12:25 PM
About sourcing tubes, it's the hardest part, I'd talk directly to the factory

Fran PiernasFeb-20 12:25 PM
Here you have one: https://www.alibaba.com/product-detail/30mA-50mA-x-ray-tube-x_570569498.html?spm=a2700.galleryofferlist.normalList.263.70744e11DbxBOd

Fran PiernasFeb-20 12:25 PM
And my tube's manufacturer: http://www.cei-xray.it/index3dab.html?l=eng in case you want an x-ray tube

anfractuosityFeb-20 12:26 PM
cool, how much was your tube? also what psu do you use for it?

Fran PiernasFeb-20 12:26 PM
However there are other ways to make x-rays, try a 2C2S tube: https://tubes-store.com/product_info.php?products_id=906

Dan MaloneyFeb-20 12:26 PM
I once had a burned out rotating anode X-ray tube that was removed from service. The tungsten target was amazingly cracked and blistered from all the use. Powerful things.

Fran PiernasFeb-20 12:26 PM
I could buy some for 2€ each on ebay

Dan MaloneyFeb-20 12:27 PM
Bet it still would have made X-rays, though. Alas, it broke when we moved.

Fran PiernasFeb-20 12:27 PM
@anfractuosity my tube was 70€, very cheap

guido.giunchiFeb-20 12:27 PM
@Fran Piernas What can you buy for 2€?

Fran PiernasFeb-20 12:27 PM
@anfractuosity also the PSU, I build it, take a look to https://hackaday.io/project/162935-piernass-fast-zvs-mazzilli-driver

Fran PiernasFeb-20 12:28 PM
@guido.giunchi a 2c2s tube, it's not designed to x-ray, but can be used for that purpose

Fran PiernasFeb-20 12:28 PM
just don't expect to have the same results as when you use a genuine x-ray tube

anfractuosityFeb-20 12:28 PM
ooh thanks a lot!

Fran PiernasFeb-20 12:28 PM
Yes, I build an x-ray machine using that tube many years ago

Fran PiernasFeb-20 12:29 PM

Fran PiernasFeb-20 12:29 PM
This is the first machine I built

neil k. sheridanFeb-20 12:29 PM
Wow it is not so expensive as I thought!

Glen SladeFeb-20 12:29 PM
@Fran Piernas Did your tube come with a scintillation screen or did you buy that separately? I could not see that part on your Xray project list.

Fran PiernasFeb-20 12:29 PM
@Glen Slade I bought the screen on ebay, an auction I won for 6€ XD

Fran PiernasFeb-20 12:30 PM
You are right, I forgot to add it to the list

Fran PiernasFeb-20 12:30 PM
It's a Fuji SpeedGreen

Glen SladeFeb-20 12:30 PM
Thanks

Fran PiernasFeb-20 12:31 PM
I designed its support and printed it

Fran PiernasFeb-20 12:31 PM

guido.giunchiFeb-20 12:31 PM
What is the smallest...
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Hack Chat Log transcript, Part 1
Lutetium • 02/21/2019 at 16:26 • 0 comments

Fran PiernasFeb-20 11:50 AM
@Jan ohhh right, yes, I have some x-rayed stuff

anfractuosityFeb-20 11:51 AM
out of interest, do you use lead shielding?

JanFeb-20 11:52 AM
yeah, that's what I'd like to know as well. and a dosimeter?

anfractuosityFeb-20 11:52 AM
mm i was wondering about that too

JanFeb-20 11:53 AM
got my my complete face x-rayed a few weeks ago (teeth) and had to wear a full body lead apron

Fran PiernasFeb-20 11:53 AM
I use a Geiger counter, it's what I have right now, but I'd like to use a proportional meter

anfractuosityFeb-20 11:54 AM
heh i've had my teeth x-rayed, i had to bite something that was very uncomfortable, not sure why, but don't think i had an apron

neil k. sheridanFeb-20 11:54 AM
that's just to keep them from moving I think!

anfractuosityFeb-20 11:54 AM
ah yeah heh

JanFeb-20 11:54 AM
yeah I had to. to keep steady for imaging

Fran PiernasFeb-20 11:55 AM
before we start, I will answer any question and that includes technical ones of course

JanFeb-20 11:55 AM
@Fran Piernas just watched your youtube x-ray video. amazing

anfractuosityFeb-20 11:55 AM
linky? don't think i've seen that

Fran PiernasFeb-20 11:55 AM
@Jan thank you so much :D

Fran PiernasFeb-20 11:56 AM
@anfractuosity here you have

anfractuosityFeb-20 11:56 AM
thanks!

JanFeb-20 11:56 AM

https://youtu.be/ASnp6982ty8?t=366

YOUTUBE MILLITESLA

JanFeb-20 11:56 AM
X-ray video is so sweet. seeing the HDD move...

Fran PiernasFeb-20 11:57 AM
my favorite part, the HDD

JanFeb-20 11:57 AM
hasn't this been done to animals and humas as well in early X-ray days?

anfractuosityFeb-20 11:57 AM
ahh, so you're using phosphor screen right? (like krasnow did too?)

JanFeb-20 11:57 AM
*humans

Fran PiernasFeb-20 11:58 AM
@Jan you mean live fluoroscopy?

Fran PiernasFeb-20 11:58 AM
Yes

Fran PiernasFeb-20 11:58 AM
@anfractuosity of course, digital screens are very, VERY expensive

anfractuosityFeb-20 11:59 AM
i'm curious, if it's possible to diy them

anfractuosityFeb-20 11:59 AM
if you skip the fibre part

Dan MaloneyFeb-20 11:59 AM
As late as the 1940s, some shoe stores had fluoroscopy machines in them to show customers how well their shoes were fitting.

Dan MaloneyFeb-20 12:00 PM
OK, folks, good turnout already and a good crowd in the chat. Let's kick it off with Fran Piernas talking about X-rays and high-voltage stuff.

Dan MaloneyFeb-20 12:01 PM
Fran, can you start us off with a little about how you got interested in this area?

Fran PiernasFeb-20 12:01 PM
Yes of course

Fran PiernasFeb-20 12:01 PM
First I will introduce myself

Fran PiernasFeb-20 12:02 PM
Hello everyone, my name is Francisco "Fran" Piernas, I'm a 23 years old physics student at University of Granada in Spain. When I was a kid, I was that kind of kid that disassembled his toys to see what they had inside. I loved to disassemble anything. Sometimes my dad gave me a broken printer for me to disassemble it, and I was the happiest kid ever lol

Fran PiernasFeb-20 12:02 PM
Then I started building small devices, until I saw a tutorial about a TV flyback using the 2n3055 transistor

Fran PiernasFeb-20 12:03 PM
And I entered the amazing world of HV stuff

Fran PiernasFeb-20 12:04 PM
If you guys haven't questions I can start talking about some HV projects I've done X)

Dan MaloneyFeb-20 12:04 PM
Cool, so much to be learned from taking stuff apart. I was always warned not to take TVs apart because of dangerous voltages. I ignored them, lol

anfractuosityFeb-20 12:05 PM
heh, how dangerous are the inside of old TVs, i'm kind of scared

anfractuosityFeb-20 12:05 PM
by the flyback things

anfractuosityFeb-20 12:05 PM
or in microwaves

Maccabees joined the room.Feb-20 12:05 PM

Fran PiernasFeb-20 12:05...
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