Good. Good.
Hi everyone. Its MSh with you.  It’s a long time since we had MSh about.  And it`s very good that finally I managed to find time for this project.
How you probably noticed I have certain attraction towards things that are one or another way related to radioactivity
Or maybe them have attraction towards me, it`s hard to know.
Because this activity is not the best for health, and worst part – impossible to see with your eyes,
that’s why to be updated about radiation levels in places that can be dangerous and under same way lower the risks for health I use radiation measurement devices, if be more accurate – dosimeter – radiometer.
In this video I will tell you about dosimeters and how they are working, and of course will show some experiments as not to overload you with boring stuff –
– will show my own devices and test over radioactive elements that I managed to collect.
For better understanding of what I am speaking off I suggest to check my video about radioactivity by pressing today.
And so: MSh about… Dosimeters
*commercial*
In this video I will touch topic about more common dosimeters. Specific chemical or colorimetry devices, methods of measuring with neutron and proton activity we will leave aside.
Will begin with the fact that thanks to the lack of knowledge name dosimeter is given towards all devices that are measuring radiation.
I will be the light that brings knowledge to people. It`s not exactly like that.
Device that shows current radiation level – in gamma rays or the same beta particles in this moment are perrcing your flesh.
If speaking correctly – measures strength of dose, is named radiometer.
And thing that measures, how much healthy rays we took or may take in certain time gap or total amount dose is dosimeter.
From word dose… so you would not have an overdose
Sometimes such devices are combined in the one body and then they are called dosimeter – radiometer.
But in simplifying second word is taken out and thanks to that we have certain technical miss understandmment
Not always this devices are combined together. If you will plan to buy one, make sure to check what are you buying.
Radiometer is comfortable to use for imidiatly checking current situation. Remember how I was walking in basement of hospital.
Then my DRG was turned into the radiometer mode. And I imdiatly saw – that it was “ducked up” here.
Oh mama even worse hell.
Accuracy of measurement here is not to high, but we need to see situation and react fast to it so it`s enough to run as far as you can.
But for more accurate measurements of dose size you will need time.
You need dosimeter that will take measures you hold it in one place while it will take measurements.
And it can be from few seconds to few minutes. And if you hold dosimeter in your hand – all filth you are catching with your hands and body as well.
That’s why for catching smaller dose , this photo, as example, I made with dosimeter placed on bag that I brought with me and hid behind the corner while it was taking measures.
Now lets talk about how dosimeters are working. Here everything is simple.
There is detector that is detecting radiation, it send signal to electrical scheme, scheme transforms it to more common for us way.
And from here fantasy is unlimited. It can be cracking and blinking and putting info on screen and voice and you can go and go.
As detectors can be used different devices. Scintillators. Ionised cameras.
I will tell you that as dosimeter can be used anything that is sensitive towards radiation. Even photo paper can be used, after all it is covered with radioactive rays.
Even photo paper can be used, after all it is covered with radioactive rays. And how much it changed will tell us about strength of the flow.
But agree that you won`t be bringing photo lab with you to make photos and fix image. And to understand it you will need some special skills and ordinary human in field won`t do it
But in home/military dosimeters usually is used Geiger counter. And with istied another mislead. Sometimes dosimeters are called that way – Geiger counters.
Like, Vasia took Geiger counter and stepend in to the reactor.
That’s a mistake.
That’s how one of versions of Geiger counters look like. One of more wide spread models - SBM-20
As you may see its just a part, without additional hardware its useless chunk of metal.  With it you will die in radioactive swamps.
But if you will give electric power to it and connect scheme of registered impulse counter, and show it somewhere – you will have a dosimeter.
But still how this pipe can see what we don`t see nor feel. It`s simple inside of this pipe there is inert gas with additions.
In the middle of it there is a metal string. Anode. Walls of counter as you see are made from metal, its cathode. To it and to the wire is given electricity.
Here are connectors for electric power. Around 400V. Distance between wire and walls is selected such that it has to be almost perrced with electricity.
And further works physics, particle is flying and hits the metal wall of device and tears our electron.
Electron after a kick in the ass flies inside in to the gas and kicking out electrons from there, ionising them.
Under influence of electromagnetic field they are gaining more and more speed while reacting with other atoms. Avalanche type increase begins.
I am like always compare everything in original way. Well probably because its me. Well lets imagine A really huge billiard table. That is placed under certain angle.
All balls are in holes, so they wouldn’t roll down. Distance between balls is different from 20cm to 1-2m. And here you hit a ball, it starts to roll down.
While doing so it will probably hit other balls. That will start to roll down as well and hit other balls 1,2,4…
and so it will be armada of balls rolling down. Approximately the same happens in Geiger counter.
And so ions are giving conductance in a gas, no wonder electric arch can burn in the air for long time despite the fact that air is by itself dielectric.
And it happens that cover is connected with wire through ion channel. current pulse appears that is tracked by a scheme. And the same scheme is putting detector in previous state.
After that its necessary to count number of impulses and show them on screen.
But if all would be so simple our life would be boring.
Same rule applies here. Main disadvantage of dosimeters based on Geiger counter is that they don’t see difference in Alfa, Beta and Gama, what flew inside the device and was registered will be shown.
And again flaws. Alpha particles fly just few centimetres in air, but after reaching counter will be registered by chance of almost 100%.
Because it`s large and heavy and will most likely touch atoms of gas that is inside. Its like roll a bowling ball through our billiard table it will most likely hit something.
Beta can manage to slip through counter and wont react with anything.  Its like fire from a paint ball gun towards our table.
Some where it will hit somewhere not and will fly further.
That’s why there is registered from 10% to 30%  of Beta particles. And Gama is registered only 1/10 of 1%. Everything passes by without touching anything.
That’s why in creation of dosimeters huge role is plaid towards algorithm of impulse counter. Thickness of device walls, material from which it was made and many other details.
And there question appears: Then how with dosimeters are measured Beta or Gama particles?
Lets experiment a little and I will tell you.
For experiment I will take my work horse with a name, Radioscan 701, lets turn it on, as a source of radiation we will use detector block from ship dosimeter.
Such slightly dangerous looking thing. Source is located inside, now we will dissemble this detector block and will pull out source.
Here were two boards, but one board was taken off by someone not good. Probably for precious metals.
Control source is probably located in this welded rubber case. And from here happily are flying out beta particles, that’s why I am not pointing it towards myself.
Nothing bad will happen if hold for a short time but still its not the best thing for your health if you will have a long term contact with it.
Measurement of beta particles is based on counting, we are measuring just outside situation with a case, as you see here is case that consists out of two parts.
Here is lead screen and plastic screen. Plastic is preventing beta particles. Lead lowers slightly gamma rays.
And so we cut out Beta rays and measure only gamma.  Through this screen goes only gamma rays. And we measure it straight over the exit hole of our source.
Now I will switch to beta.
Beta mode.
It asks me to put on the lid. And so I put lid on and press button to take measures.
After that we measure it by putting it as close as possible.
Now it measured certain amount of particles that are without beta, without beta we managed to get 570 particles,
now we take off the lid and by doing so we strip off our Geiger counter and now towards it will fly everything.
As well we will catch some gamma rays that’s why this measuring way has a flaw. But its not crucial. And beta rays will be counted completely.
That`s why we go to the beta measuring mode.  It says to us that we have to take of the lid, and we begin measurements.
Immediately it shows us result and counting out what we had it shows us almost with 5000 particles per cm^2/min that is large quantity if considered.
That’s how beta is measured. I hope this will be really helpful for someone.
Apart from Geiger counters as I told early, for measuring radiation can be used siciliators or ionised cameras.
And about last ones we will talk more wide.
Because they are main part of individual dosimeter – collector, similar to the one that is in my hands, its similar to dosimeter-collectors that were used by liquidators,
similar to the one that I was taking to the illegal trip in to the Pripyat.
And so we will study it in a wider range.
And so how this individual dosimeter – collector works? Main part of it is ionising chamber, that gets certain amount of voltage and that way it charges, and gains certain potential.
Just like capacitor. Radioactive particle when flies through capacitor, create small discharge of it. The higher number of such particles the stronger and faster discharge of capacitor happen.
And now try to remember such moment from your childhood. I don’t know were you doing so , but I had such moments.
You take some paper and rub it on fur or hair, or give some electric charge to the fur and drop all those papers on it.
They stick to the fur but papers that are close to each other may push a part, because they are charged with same type of electricity.
similar thing happens here. But in here is used not a sheet of paper but a small string.
When you walk through the place that is highly radioactive, your capacitor starts to discharge, its charge I falling down and this sheet starts to fall down.
And while doing so it moves over the scale and you can see what dose you received.
This device has scale up to 200 mR, to discharge it completely you will as example in that hospital basement spend not a small amount of time. Probably few hours.
Agree that its not a small time gap. Such devices are used in civil defence, were used by liquidators – that means in ordinary life you wont have any use from them, because there is no such high levels of radiation here.
And now guys lets talk about my dosimeters. That I use, or not use because of one or another case. First one back in 2007-08 I got first dosimeter DRG-01T1.
Good device that measures in really wide range, that if will be necessary most like it will be true hell outside. And from it I started measurements of interesting for me places.
As example I live in Gatchina, so first thing I did was I made a circle around St. Petersburg nuclear science academy and measured everything there, but haven’t found anything.
Dosimeter has a wide range  - and that is his big advantage.
His disadvantages are – it measures only gamma rays, because here is thick layer of steel that completely blocks beta rays. And it has its flaws in it.
Second disadvantage is that it doesn’t have noise signal. It has light, I don’t know if you see it. It has a liquid crystal display that is light up with small light on a side. Here you can see it.
It has light but doesn’t have audio signal. That’s why when you go somewhere with it you have to look at it all the time.
If you wont look at it, you may by accident go through a dangerous zone and catch something on you.
Despite that I used this device on my trip to Pripyat and it was showing decent information, when I was checking on two dosimeters at the same time.
One of the bigger disadvantages is that it doesn’t measure in beta.  Not long ago we measured amount of beta particles on cm^2 that were coming from this hole.
Lets now measure with dosimeter what it will show in gamma.
Now it will take some time to measure it.
And it shows 58mR. That isn`t that much, its only few times higher then normal levels  Amount of particles we had was just enormous. That’s why with it you have to be careful.
This dosimeter can work in dosimeter mode and in radiometer mode, in radiometer mode I was using it when I was walking through basement of hospital.
It doesn’t show very precisely, as you may see data is constantly changing, it shows 30 mR then 10mR and again.
But despite that when numbers flew up it was obvious that its no, no, no not good.
In dosimeter is used Geiger counterSBM20 and SI34 or SI40, in descriptions they write everywhere differently.
By the way lets try with a help of this device measure power from control device DP5A.
This device came to me not long ago and that’s why there is a lot of work to be done over it, it has to be restored that’s why I don’t use it.
But it has interesting part. It has control source – based on strontium. Its separate topic.
It`s covered with such metal screen, now I will pull it out and it will begin to glow not in a light way.
So lets open it, here is a metal plate in here is welded piece of strontium.
Now lets see how much it glows with help of DRG dosimeter. Dosimeter doesn’t feel any beta rays from this source, it only shows 23 mR.
And now let see what my radioscan will show to us. I even turn on the sound. It shows around 100 mR. That is not bad if considered.
Now lets measure in beta how much particles fly out of this source. 5200 particles. If I will switch on the sound, you will be shocked.
Advantage of audio signal – you can guess where it`s more dangerous.
Let say dosimeter is near my face, as you may see everything is fine.
You may have taught that I am under bombardment of particles, but its not like that as beta particles don’t fly that much through the air.
But when we move device closer to the source he can feel how it increases and increases.
And then it goes completely insane. I put it over the source it shows 7400 particles , let me put it like this.
Good, very good. Here in a distance of about 1cm because here is small metal thing, 23000-23500 particles fly from it. Its of course  a lot.
Lets say that I don’t measure it correctly because for measuring beta you need measure with lids on and off while its in a same distance and I was playing with distances here.
But despite that you can feel how much of different junk is flying out of here per second. That’s why I think we will now close the screen.
And will be calm. By the way do you see how the screen protects?
That’s it creation of hell shut yourself.
That’s what you can find in post soviet union countries. What I like a lot in DP5A just like all DPs are with such nice green case.
Here is space for external power supply its located on that side.
Headphones. Different pads and of course manual.  With time I will fix it all.
By the way on top is fixed stick for detector block.
You may use it to scan car wheals as example to check if it haven’t brought some nasty stuff on them.  That’s why when I will manage to launch it, it will be separate video I think.
When using dosimeter, I want to tell, you bring it close to contaminated surface or surface that can be contaminated, but you don’t know about that.
Try not to touch it with work surface of dosimeter. Because from that surface particle can stuck to the surface or will even get inside and will create not right information.
That’s why remember this and be careful.
Exactly that’s why I put this dosimeter over the bag when was making photos in the basement of hospital.
Bag was clean so dirt got on that side and this side was clean so you could put dosimeter on it.
Apart from this dosimeters, I have such MKS – good professional device, but when I received it, it was reprogramed in strange way so I can`t use it properly.
“Device is ready for work” – here is voiced measuring.
Gamma 99% fault but now it will decrease.
And later woman voice will say that radiation level is normal, but this dosimeter can measure beta, alpha but its impossible to switch between them, because it shows only sound on, sound off.
Gamma, dose, clear dose and that is. Its programmed in strange so for now its not to use.
“device is off” hmm, pleasant voice.
Here as well is used Geiger counter. Type beta 1, I can`t use this device, but in comparison to this one it has one good advantage – lid can move to the side.
So in this case you have to remove lid and if your hands are growing from wrong place you may by accident lose it. But that’s small thing.
By itself I like this device because it has comfortable interface, everything is displayed comfortable its compact and is weighting less then even this MKS.
Probably here is bigger board inside. And here technical decisions were made towards compactness. And that’s why with it I feel more comfortable to walk. Not like with DRG that doesn’t measure beta.
And because in Chernobyl zone radiation is created mostly because of strontium and cesium that are beta active, thas why you have to measure beta and with it you feel more secure.
That is what I will tell you. Device works from two AAA batteries and you can connect via USB port it towards computer
and transfer its log that it creates with information about doses that I gathered and so on. So you can play with it for some time.
You can reprogram it, so its such small computer- dosimeter – radiometer.
One more gift was made by Serz Petrov, thank you Serz. This gift arrived from a mountain Beshtau -that is in Caucasus.
There are located mines where some time ago uranium was mined. And here in front of you is small peace of mineral called Shrekingerit.
Interesting name, from a word Shrek. This mineral glows in the dark, under UV light. Very eye catching sight.
That’s why lets get somewhere inside and put some light on it.
Darkness friend of teens my friends.
In my hands is a torch light that glows in UV spectre. In reality it`s standart chines torch light.
But diode is not usual, but as well chines. Diode glows in UV. But I will open small secret for you that you could have not known.
All the torches that glow in white or other colour are glowing as well in UV.
But they are covered in phosphor that pushes spectre towards more common for us are white, or warm yellow, orange colour.
But here there is no phosphor. And that’s why torch glows in something like this.
Lets switch off our light for now and look how mineral Shrekingerit will react under UV light.
As you can see particles of Shrekingerit started to glow in the rock.  I don’t put light straight over it because it will disorder image.
That’s the beauty. And now imagine to yourself how it would look if with strong UV light to light somewhere where this mineral was mined.
From another side – being there is dangerous for your health. Because this mineral contains uranium in it.
Uranium is alpha radioactive, following that if you will breath dust of this mineral inside of you will appear source of alpha radiation that is most lethal for humans.
That’s why we can describe it as a deadly beauty. And its better look at it over the video screen.
In my case its just a small rock that I keep inside the foil, holding all the alpha rays and thanks to that nothing bad will happen to me, despite this you have to be careful with such things.
And now lets switch soffit on. And all the magic disappears. And only in UV all this will be possible to see.
Dosimeter says that it can measure alpha but spread of alpha in the air is small so how it catches it, honestly, I can`t understand.
But despite that lets switch it to the alpha mode. Choose alpha.
Alpha it prefers to measure exactly the same way – put on the lid. Its probably necessary to put it this way to cut off everything.
It managed to catch 430 particles flying from this mineral in to the air. Of course you have to measure alpha by pressing it straight to the source.
We have foil here and etc. so we don’t have 100% smooth surface. But despite that this mineral is slightly radioactive.
Of course if I will switch on gamma – 34 mR is nothing serious that you should be worried of.
I set up certain steps over every mode: beta, alpha, gamma. You can put two steps, first one is 30 mR as healthy second one is high roentgens about which I don’t thing about.
So that the mineral, again, Serz – thank you.
And so friends lets look how different items can decrease betta rays. 4700 maximal number that I managed to get.
Lets take 1000 RUB note and check how much it will help us. 1000 RUB doesn’t let us to get into the range of 4000 particles, that means at least 500 particles it manages to hold up, and that isn’t bad.
Now lets take 2000 RUB. With 2000 RUB  amount of particles is equal to around 3400.
And now 3000 RUB as I don’t have any more money until salary. That’s why don’t wait for continuation of action.
By the way money won`t become radioactive, for them become radioactive you have to affect them with neutrons.
That’s why particles – electrons that are firing through my notes fly further or get stuck somewhere in molecules of the notes and because of that nothing will happen.
Because of that nothing will happen to the money or to those who will use them later.
And now its around 3000, so notes stopped around 1500.
Each such note takes around 500 particles on it self.
What can phone do?
Phone works as well in a good way as alternative to the lead screen. But it`s more expensive and thicker.
How foil will prevent beta rays? It seems that is foil is made out of $£”!@”~ because it basically doesn’t stop any particles. As well 3500 so chunk of foil is equal to few notes.
One of the highest dangers of beta rays are eye burns because eyes and all the insides are not protected in any way.
That’s why I now took my sunglasses which I almost don`t take off because of the good weather. Lets check what if I will be in the glasses how many particles will fly towards me?
Well something will reach me but sunglasses really prevent something. Even better then foil by my surprise.
And now interesting part. Lets see how much beta rays are blocked by my t-shirt. That I have over my body.
It almost doesn’t fall 3500 particles so it stopped around 1000 particles. Its pleasant to see, but clothes are not something protective against beta rays.
Best protection against beta is distance. As you may see here its almost undetectable. Around  100 particles.
That is why in Chernobyl exclusion zone its prohibited for kids to be there, because kids of short height and beta particles manage to reach their reproduction parts, their bodies and in that way damage future development of body.
And for adults everything is basically without need and they are slightly higher.
Of course dosimetry topic is large and wide. It`s possible to speak about it for hours and make out of it Santa Barbara.
Besides I by myself don’t have all the necessary knowledge so I could read long lectures. That’s why we can end up over this.
I hope you understood that there is no such thing as perfect dosimeter.  But there are more accurate. Most important is to know how to use them.
Be aware and watch for your safety, I hope I was interesting and helpful.
If yes then press thumbs up and subscribe as its best way to say thank you to me. If you have questions and fact supported criticism then welcome to comments.
I will try to answer the more logical questions.
Good luck, watch your self and see you next time. It was MSh with you.
Thanck's for sub - Sergej Koroliovas
