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Hack Chat Transcript, Part 2

A event log for X-Rays and High Voltage Hack Chat

Hacking on the edge of the danger zone

LutetiumLutetium 02/21/2019 at 16:290 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 dot you can resolve in your xray machine?

Fran PiernasFeb-20 12:32 PM
@guido.giunchi what do you mean, the smallest thing I can see?

Dan MaloneyFeb-20 12:32 PM
I'd think it would be limited by the grain of the phosphor screen, no?

Fran PiernasFeb-20 12:33 PM
Yes, high speed screens are do emmit more light

Fran PiernasFeb-20 12:33 PM
however they are worse at resolution

Fran PiernasFeb-20 12:34 PM
But I haven't ever had a problem with mine

Dan MaloneyFeb-20 12:34 PM
It's also a function of the cathode size, as I recall from my radiologic technologist days. The larger the cathode, the less detail you can get.

Fran PiernasFeb-20 12:34 PM
Yes, you want a point like x-ray emmiter

Martin Simlastik has been added to the team.Feb-20 12:34 PM

Dan MaloneyFeb-20 12:34 PM
Dental tubes have pretty small cathodes, if I recall correctly

guido.giunchiFeb-20 12:34 PM
Yes, how detailed can you your scans get?

Fran PiernasFeb-20 12:34 PM
Yes, the focus is very small

Fran PiernasFeb-20 12:35 PM
@guido.giunchi here you have some examples:

Fran PiernasFeb-20 12:35 PM

Fran PiernasFeb-20 12:35 PM

Fran PiernasFeb-20 12:35 PM
you see it works pretty well

Fran PiernasFeb-20 12:36 PM
Do you guys have an automatic breaker at your houses?

Fran PiernasFeb-20 12:36 PM

Fran PiernasFeb-20 12:36 PM
That's how it works

Dan MaloneyFeb-20 12:36 PM
@Fran Piernas , I think you mentioned that you're not even in the room when the X-ray is on. Is that correct?

Dan MaloneyFeb-20 12:36 PM
Neat! I love the circuit breaker shots!

Fran PiernasFeb-20 12:37 PM
I'm not, I set a countdown and leave the room, then I go to another room where I didn't measure radiation and stay

Fran PiernasFeb-20 12:37 PM
Or a use a remote desktop app to connect to the laptop

Fran PiernasFeb-20 12:37 PM
and from it, send the command to the machine

Fran PiernasFeb-20 12:38 PM

Fran PiernasFeb-20 12:38 PM
This example of the iphone, I like it a lot

Dan MaloneyFeb-20 12:38 PM
Smart move. Have you ever measured the maximum dose your setup can deliver?

Fran PiernasFeb-20 12:38 PM
it shows the haptic engine

Fran PiernasFeb-20 12:38 PM
@Dan Maloney I did some measurements, like this:

Fran PiernasFeb-20 12:39 PM

https://www.youtube.com/watch?v=xqsy9tpHCf0

YOUTUBE MILLITESLA

Fran PiernasFeb-20 12:39 PM
However, it's a counter so it counts radiation, it's bad at measuring high radiation

Fran PiernasFeb-20 12:39 PM
a proportional meter has to be used for this

Nevermore78Feb-20 12:40 PM
@Fran Piernas how far was that from the tube?

Fran PiernasFeb-20 12:40 PM
@Nevermore78 if I'm correct, 2 meters

Dan MaloneyFeb-20 12:40 PM
Yeah, but still - that thing isn't fooling around! Good to be careful with it.

guido.giunchiFeb-20 12:40 PM
The shots are insanely cool! Do you ever think you can put yourself in danger with the high voltage and radiations?

Fran PiernasFeb-20 12:41 PM
@guido.giunchi I don't think I'm getting radiation, I got to a room where I measured nothing but background radiation

Fran PiernasFeb-20 12:42 PM
and about HV

Nevermore78Feb-20 12:42 PM
how is the radiation pattern around the machine?

neil k. sheridanFeb-20 12:42 PM
You could wear one of these! https://en.wikipedia.org/wiki/Film_badge_dosimeter

Fran PiernasFeb-20 12:42 PM
a pair of gloves do the trick, also If you are working with very HV, like >50000V, use liquid paraffin

Fran PiernasFeb-20 12:43 PM
that's something that made me got mad, I spent a lot of time looking for HV insulators

Fran PiernasFeb-20 12:44 PM
some people uses sunflower oil

Fran PiernasFeb-20 12:44 PM
and I found that liquid paraffin from the pharmacy is a los cleaner and better

Fran PiernasFeb-20 12:45 PM
@Nevermore78 it's hard to know, the machine does have lead shielding, but when it's activated, there is radiation in the hole room, mostly because of backscattered x-rays

Dan MaloneyFeb-20 12:45 PM
@neil k. sheridan - I followed that link and clicked through on "electronic personal dosimeter" - pretty cool, they're using PIN diodes and MOSFETs as sensors in all-electronic dosimeters now. No need to send film off to be developed.

vincent stuchlyFeb-20 12:46 PM
like you apply oil/paraffin to the gloves, right? I am hearing this for the first time so sorry for stupid question

neil k. sheridanFeb-20 12:46 PM
@Dan Maloney ooh! Interesting I will have a look at that!

Fran PiernasFeb-20 12:46 PM
@vincent stuchly in fact you take you HV stuff and put it in liquid paraffin

Fran PiernasFeb-20 12:46 PM
just like I did with the multipler

Nevermore78Feb-20 12:46 PM
right, haven't thought of backscatter!

Dan MaloneyFeb-20 12:46 PM
FYI, liquid paraffin is also called mineral oil here in the States. NOT baby oil - that has fragrance added.

Fran PiernasFeb-20 12:46 PM

vincent stuchlyFeb-20 12:47 PM
oh my bad, sorry got bit confused :D

Fran PiernasFeb-20 12:47 PM
it's full of liquid paraffin (mineral oil) in there

Fran PiernasFeb-20 12:47 PM
There are alternatives, oils that are designed for this purpose, but they are hard to find and very expensive

Fran PiernasFeb-20 12:48 PM
I bought 1 liter of mineral oil for 10€

Dan MaloneyFeb-20 12:48 PM

https://hackaday.com/2018/09/18/a-look-at-liquid-dielectrics/

HACKADAY DAN MALONEY

A Look at Liquid Dielectrics

One evening quite a few years ago, as I was driving through my hometown I saw the telltale flashing lights of the local volunteer fire department ahead. I passed by a side road where all the activity was: a utility pole on fire.

Read this on Hackaday

Fran PiernasFeb-20 12:48 PM

Fran PiernasFeb-20 12:49 PM
I did a test to the oil to see if it was suitable

Fran PiernasFeb-20 12:49 PM

https://www.youtube.com/watch?v=5ARtZICuqGg

YOUTUBE MILLITESLA

Fran PiernasFeb-20 12:49 PM
the oil managed to stop arcs, as long as you avoid hard edged or corona effect will happen

JarrettFeb-20 12:50 PM
ooh

JarrettFeb-20 12:50 PM
what about kerosene?

JarrettFeb-20 12:50 PM
sorry haven't read scrollback

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