Let's get started!

-= Wolf =-3:06 PM
pollution is definitely an unresolved issue in the copper industry, the amount of unusable bi products is astounding

Today in the chat, we have @Radu hosting

@Radu Motisan

Radu is from Romania, and was a Hackaday Prize finalist in 2014

Rebecca E. Skinner3:07 PM
I just joined (didn't know the meeting would start early). Where is this mine, and what sort of acidic compound (liquid I gather) is being dredged to avoid soaking into ground/ groundwater ?

welcome, can you introduce yourself, and tell us a little about what you're working on?

@Rebecca E. Skinner HI, we're just getting started with an intro from Radu

Radu Motisan3:09 PM
Sure! I was trained as a software developer, but for a few years now I'm more into hardware

Radu Motisan3:09 PM
They are pretty much joined nowadays anyway

Radu Motisan3:09 PM
but I always wanted to get out of the virtual screen :)

Radu Motisan3:10 PM
So about my work
Christian Moll joined the room.3:11 PM

Radu Motisan3:11 PM
Back in 2012 I built a device with integrated internet connectivity

Radu Motisan3:12 PM
It was before IOT became a buzzword
victor.aprea joined the room.3:12 PM

Radu Motisan3:13 PM
It was equipped with ionizating radiation sensors and I was interested in seeing 24/7 readings

Radu Motisan3:13 PM
this came after many other projects I posted on my blog

Radu Motisan3:14 PM
back then I had a lot of time to play :)

Radu Motisan3:14 PM
this one got a lot of attention, also thanks to HaD where it was features

Radu Motisan3:14 PM
*featured

-= Wolf =-3:14 PM
what was the device used for/purpose?

Radu Motisan3:14 PM
(sorry for any typos, I'm currently on road through Serbia, so hello to @Aleksandar Bradic if he's arround)

certainly @Dusan Petrovic is around in Belgrade

Radu Motisan3:15 PM
@Sophi Kravitz awesome . Hi !

Radu Motisan3:15 PM
@-= Wolf =- it was a number of sensors

Radu Motisan3:16 PM
connected to the internet

Radu Motisan3:16 PM
the main one was a sensitive Geiger tube

Radu Motisan3:16 PM
to observe background radiation levels and fluctuations related to various phenomenons

Radu Motisan3:16 PM
there were other sensors too

what kind of signal does the Geiger tube put out? Like on/off or proportional

Radu Motisan3:16 PM
it's just on / off, like a radiation triggered switch

Radu Motisan3:17 PM
so one needs to count the pulses per time period to get an idea on the dose

Radu Motisan3:17 PM
there's more to ionising radiation than that

Jacob Dice3:17 PM
The data viz for this project is fantastic: https://www.uradmonitor.com/

Radu Motisan3:17 PM
like type (alpha, beta, etc) and energy

Radu Motisan3:18 PM
@Jacob Dice thanks, there's a lot to do there still

Radu Motisan3:18 PM
since there's a lot of data

Radu Motisan3:18 PM
the software tools are becoming complicated

Radu Motisan3:18 PM
for instance the database contains now hundreds of millions of entries

Radu Motisan3:19 PM
but all in one this is how it started

Jacob Dice3:19 PM
Who is the primary user/who utilizes the sensors?

Radu Motisan3:19 PM
I love the idea that a tiny microcontroller (back then an atmega168) could pack in network protocols

Rebecca E. Skinner3:19 PM
So the device is a Geiger counter with greatly improved data and presentation capacity ?

Radu Motisan3:19 PM
and do all its work by itself

victor.aprea3:19 PM
Radu, i'd like to hear about your experience with the Winsensor gas sensors, how did you come to choose them (as a company, and the ZE03 series in particular), have they performed well for you?

Radu Motisan3:20 PM
@Jacob Dice the project raised interest in the tech communities at first

Radu Motisan3:20 PM
it was a very niche direction, but managed to work out and support the further development

victor.aprea3:20 PM
p.s. this is my first hackchat, is there an audio feed somewhere, or is it all text-based

Radu Motisan3:20 PM
@Rebecca E. Skinner initially it was a geiger counter with internet connectivity

@victor.aprea HI

@victor.aprea all text based

victor.aprea3:21 PM
hi Sophi, thanks!

Radu Motisan3:21 PM
@Rebecca E. Skinner more sensors were added later to the existing infrastructure

Radu Motisan3:21 PM
but in the beginning it was just the geiger counter

how does the Geiger tube know the difference between Alpha and Beta waves

?

pop133:22 PM
It dosent

Radu Motisan3:22 PM
actually it does

Radu Motisan3:22 PM
one would need to use additional screens or filters to block one or the other

Kris Winer3:22 PM
Charges are different, as well as mass...

Radu Motisan3:23 PM
then let the tube do the counting

pop133:23 PM
You can only filter out types of radia

pop133:23 PM
tion

Radu Motisan3:23 PM
yes, either alpha or beta in this case

Radu Motisan3:23 PM
a piece of paper will block alphas

Radu Motisan3:23 PM
while betas will pass

Radu Motisan3:23 PM
a piece of aluminium foil will block the betas

Radu Motisan3:24 PM
but other materials are used, for instance mica windows are used in alpha/beta geiger tubes

Radu Motisan3:24 PM
the tube is a metal tube but with a mica window

does the beta get thru the mica?

Radu Motisan3:24 PM
a hackaday prize finalist project I did used such a tube in 2015

Radu Motisan3:25 PM
yes

pop133:25 PM
https://en.m.wikipedia.org/wiki/Radiation cthere is a nice picture in this article which explains it

Radu Motisan3:25 PM
alpha can be affected after a certain thickness

thanks @pop13 !

Radu Motisan3:26 PM
gamma radiation and x-rays have a good penetration power

Radu Motisan3:26 PM
anyway, a book that's excellent on all theoretical aspects and it is very accessible and useful on all levels, is the Centronic's Geiger tube theory

Radu Motisan3:26 PM
there's a lot to these simple detectors

Radu Motisan3:26 PM
both cons and pros

Radu Motisan3:27 PM
I had to find a radiation sensor that would fit the budget in order to put everything into production and scale to more than an initial prototype

Radu Motisan3:27 PM
geiger tubes have a simple working principle

Radu Motisan3:27 PM
as said they work like a switch

Radu Motisan3:28 PM
there 's this tube with two electrodes

Radu Motisan3:28 PM
and a low pressure gas of a special kind

Radu Motisan3:28 PM
incident radiation will ionise the gas, creating a conductive path between the two electrodes where a potential difference is applied

Radu Motisan3:29 PM
so as a result, the circuit will close, resulting in a pulse on a counting circuit

Radu Motisan3:29 PM
the gas is special because it needs to neutralise the conductive path immediately after it was formed

Jacob Dice3:29 PM
Did you filter the uRad sensor to specifically count one of the radiation types or block specific kinds?

Radu Motisan3:29 PM
this is why it is called "quenching gas"

Radu Motisan3:30 PM
not on the first models, that were using gamma only sensors

Radu Motisan3:30 PM
the tubes inside also allowed hard beta radiation, but due to the design on the device, those were filtered out (thick aluminium enclosure)

pop133:30 PM
Why did you use a GM tube  scintillation detectors were too expensive? Or why didnt you use semiconductor based ones?

Radu Motisan3:30 PM
@pop13 yes, you are right. because of price considerations

Radu Motisan3:31 PM
scintillation detectors provide great advantages, but like with everything in life there's a balance between what you pay and what you get

Radu Motisan3:31 PM
traditional  detectors were using a crystal and a photomultiplier tube

Radu Motisan3:32 PM
and give indications on incident particle energy

Radu Motisan3:32 PM
so you would have not only the counts per minute (cpm, like for geiger tubes), but also the incident radiation energy

Radu Motisan3:32 PM
sorry for miscalling it "particle" two lines above :)

Radu Motisan3:33 PM
having the energy readings is interesting, as one can do a fourier transformation and do a spectrum on the input data

Radu Motisan3:33 PM
this way you can identify the type of the source emitting the radiation

Radu Motisan3:33 PM
you can see if a radioactive material contains Cesium 137 or other isotopes with great accuracy in real time

pop133:34 PM
That would be a nice hack using cheap camera sensors, place them onto a board cover them from light abd detect the particles striking the sensors.

Radu Motisan3:34 PM
all this can be done with semiconductors too

Radu Motisan3:34 PM
but sensitivity is a big issue there, unless you are prepared to pay a lot

Radu Motisan3:34 PM
again the price balance issue limiting design options

Rebecca E. Skinner3:34 PM
It's kind of obvious to ask this, but what's the relationship between observed radiation and proximity to northern Ukraine ?

Radu Motisan3:35 PM
the scintillation crystals have different densities, there are various materials available, but just think of what Cesium Iodide is

Radu Motisan3:36 PM
and this is important on the radiation absorption factor, since you will not detect what passes in and out of your detector unaffected

pop133:36 PM
The camera based aolution wpuld definitely require somekind if pld or fpga to handle the d

Jacob Dice3:37 PM
What was your interest in creating a radiation sensor to map ratiation levels across the world? Health concerns, public safety, institutional policy change, just curiousity, etc?

Radu Motisan3:37 PM
@Rebecca E. Skinner we need more resolution and closer proximity, as radiation itself has a short path, like any radiation fields, decreasing with the distance square

Radu Motisan3:37 PM
but generally direct links to soil types were easily observed

Radu Motisan3:37 PM
soils rich in uranium or thorium ore

Radu Motisan3:37 PM
sure, people are unaware of all these "small" details

Radu Motisan3:38 PM
@pop13 not quite

Radu Motisan3:38 PM
@pop13  I need to detail this

pop133:38 PM
Sorry stuff from clipboard just ignore pls

Radu Motisan3:38 PM
so as said , you have your detector and radiation passes right through it

Radu Motisan3:39 PM
if the energy is very high, it will pass right through

Radu Motisan3:39 PM
you need your detector to have a given volume of a considerable (big) density to make sure your detector will absorb the incident radiation

Radu Motisan3:39 PM
absorption means that some of the incident radiation's energy will be transferred to your detector

Radu Motisan3:40 PM
if your detector is a thin CCD semiconductor, only low energy radiation will be absorbed

Radu Motisan3:40 PM
all rest will pass right through it and you will see nothing

Radu Motisan3:40 PM
but on the  other hand, low energy will be stopped by the lenses before it reaches the CCD

Radu Motisan3:41 PM
so you don't really have a working solution here

Radu Motisan3:41 PM
you will need to couple the CCD with a scintillator

Radu Motisan3:41 PM
this is already how crystal+photomultiplier probes work

pop133:41 PM
So it will realy work fir alpha and nit beta or gamma

Radu Motisan3:41 PM
or even better, high surface PIN photodiodes coupled with crystals

Radu Motisan3:42 PM
it will work for all radiation types, including neutrons, you'll just need to carefully select your scintillation material

Radu Motisan3:42 PM
and in some cases use a moderator

Radu Motisan3:42 PM
for instance for neutrons, you will need paraffin (other options are available) to slow them down

Radu Motisan3:42 PM
as for the processing itself

Radu Motisan3:42 PM
that's easy on a CCD

Radu Motisan3:42 PM
here

Radu Motisan3:43 PM
here's a little demo I made some time ago:

Radu Motisan3:43 PM

YOUTUBE RADU MOTISAN

Radu Motisan3:43 PM
I'll try not to post many links, not to move you guys out of this window too often

pop133:44 PM
Thanks

Radu Motisan3:44 PM
so on a CCD you'll see random pictures in total darkness

Radu Motisan3:44 PM
pixels*

Radu Motisan3:45 PM
again , sorry for the typos, I did about 1000km today, going home from sunny Greece

Radu Motisan3:45 PM
love to talk about ionising radiation after all the UV exposure I got (on those nice beaches hehe)

lol

Radu Motisan3:45 PM
so choosing the sensor can be an issue due to costs

victor.aprea3:46 PM
jealous, i'm half Greek and have never been to Greece!