Опасная зона

Опасная зона

Sunday, January 12, 2014

Twinkle, Twinkle, Little Light

At Amazon you can buy tritium. Really.

Tritium is an isotope of hydrogen, the nucleus consists of 2 neutrons in addition to the positively charged proton. That makes it unstable, and tritium decays converting one of its neutrons into a proton and an electron i.e. beta-minus decay.

In other words, tritium is radioactive.

To my knowledge, tritium is rather expensive and in fact even in laboratories a rare sight. Most prominent uses is for thermonuclear weapons and fusion reactors, as it is the easiest reaction to fuse tritium with another hydrogen isotope called deuterium (one proton and one neutron) while releasing energy.

So, at Amazon you can buy tritium gas lights which are small glass ampules filled with tritium gas and a radioluminescent material.
Medium sized tritium gas light from FireFly.

The electrons released from the beta decay are stopped in the radioluminescent material which in turn will release the energy in form of photons in the visible spectrum (...what a fancy way of saying "to shine").
This is similar to an old-fashioned TV-tube, where an electron beam (electronically accelerated to about 15 keV) hits the screen coated with radioluminescent colors and makes it shine. The electron energy released by decaying tritium is lower, only 5.7 keV, which is so low they are easily stopped even in air.

The half-live of tritium is about 12.3 years, so in 12.3 years the source will be half as bright. This is rather amazing, the gas light shines and shines and keeps shining... no batteries, no recharging.

Several different radioluminescent materials can be added to produce different colors.


I bought a couple of green ones, as well as blue, white and something in between white and blue. The green ones clearly have the best yield, probably also because the eye is most sensitive in the green region.

How bright are they? Well, clearly in normal ambient light, they are not noticeable. In the picture below I have three tritium gas lights in three sizes. The two smaller ones are green, the largest one is white.

Three tritium gas lights.
Wie Sie sehen, sehen Sie nichts.
But as the lights are dimmed and the eye adapts...

This is pretty much how the human eye sees them whey you are in complete darkness.

More or less as the adapted eye sees them. Light parts a bit weaker, and the dark parts brighter, the dynamic range of the camera is a bit narrow.
The gas lights are bright enough that you can recognize things in a complete dark room, like position of a bed, cupboard etc. The white one is not bright enough to see colors when the eye is in night vision mode, but still bright enough to read texts a few cm from the light.

Just to brighten it up, I made a long-term exposure (5 mins, iso 100) of the set.

Shine bright like a diamond.
It should be added that some of the sources which are sold on Amazon may be illegal to posses without a permit. The smallest one has < 1 GBq. The white large one has < 15 GBq.
In Germany rules are that closed tritium sources below < 1 GBq are allowed without any permit. Any sources above 1 GBq can be fined with up to 50.000 €. Similar rules are in Denmark, so these sources are kept at my University which has the necessary permits. (Used for teaching BTW, I am surprised how many students never have heard about tritium.)

Nonetheless, there is no way any dangerous radiation can escape the glass ampule within the perspex holder in normal operating conditions. Tritium behaves as hydrogen, so if one would break them open, burn the gas, condensate the resulting super heavy water vapor, and be silly enough to drink that super heavy water, you might receive a dose, possibly in the mSv region. (Most likely it will be automatically diluted before any intake can happen, so one really has to be very dedicated to be that foolish.)

Tritium is a waste product from water moderated nuclear reactors when in normal operation. Following the wikipedia article on tritium, over 41000 curies of tritium was released in 2003 which would be enough to make 1.5 million of the smallest tritium gas light shown above.

Anyway, I can recommend the small ones as geeky gifts for geeky physicists. There is some strange fascination in seeing this light with no batteries, or phosphorescence pre-activation - just radioactive decay and radioluminescense. One cannot help but getting philosophical contemplating the light. Where does the energy come from... and 1 billion beta decays per second (for a fresh 1 GBq source ). Think 1 - 0.5 billion decays per second for 12.3 years and then you have used up half of the tritium. Amazing.

Oh, and I submerged one into the bottom of my little aquarium. Green light shining on the ocean floor at night. :-)

[link to photo album]


Sunday, April 28, 2013

Tripoint Borders III: Poland, Czech Republic and Slovakia

Continuing my Tripoint in Europe project, I once again ventured into the depths of central Europe. After escaping the office, I went by train to Poland, where my secondary objectives were to visit GdańskWrocław and Krakow. The primary objective was to reach the tripoint between Poland, the Czech Republic and Slovakia.

Accessing the actual tripoint is easy by car if you come from the Polish side, however if you use public transportation things may need a little planning.

View Larger Map

Initially my plan was to leave Krakow early, and go by train to the Slovakian village Skalite, which apparently is the closest spot with some sort of accommodation - I thought it would be too stressful to attempt to do it in one day.

Just in case, I attempted to reserve a room at Hotel Kolonial. I was a bit worried I might end up in Skalite with no trains, no taxis and no place to stay. Tried to call them:

- "English?"
- "No."
- "Deutsch?"
- "No."
- "Po Russki?"
- "No."
- "Uhh...."
- "Iba slovenské alebo poľské."
- "Alright...."
- "Send email, ok?"
- "Ok, right. Dakujem."

Which I did, but no response came. Then I had a polish friend calling him, all seemed ok, had to SMS the details. Ok. No reply. Guess it's ok then, I'm just stressing out.

Next thing was to arrange travels to Skalite. Idea was to go from Krakow to Zwardon (a small Polish village just at the border to Slovakia). Now, In Wrocław there was a beautiful new renovated train station, so I might just get the tickets right away, again with some help from friends.

The "administrative system" inside the nicely renovated train station clearly has not been renovated: going to the domestic ticket booths, there were three queues to choose from. The first one I took, was wrong: "This company does not service Zwardon. Go to next booth."
Re-queue in another line. I earlier wrote down the connection details which I found on www.bahn.de.

- (Showing paper saying my destination.) "Zwardon."
- "Gdzie?"
- Oh, sorry, I spelled it wrong, "d" was missing. (I could swear I thought I got it right.)
- Aha. (Pause.) No.
- No?
- That connection is not possible.
- Uh-um...

Anyway, after retrying in Krakow, it turned out my idea to go all the way by train (yeah, I love trains ) seemed to be a stupid idea. Instead of a 6-hour ride, one can take a 1-hour ride with bus from Krakow to Żywiec (which hosts a major Brewery, therefore known by all locals and beyond). In Żywiec then there is a local train to Zwardon and from there ...  well if all fails, my destination for the night Skalite is just 5-7 km further, so I might just walk.

I left Krakow by bus departing from the bus terminal behind the main train station around noon. The weird thing about that ride was the crazy amount of furniture shops in the villages. It was like 60% of all shops specialized in selling furniture, very surreal.

Arriving in Żywiec there was again plenty of time to get the ticket for the next part. "Do Zwardon." "Dwe?" "Tolka odin". Languages are kind of weird. Young people are good at English, elderly more into German, and then there is a group of people who know neither. The five words of Russian I know come in very handy here, even though I was told that some people may be a annoyed if you approach them with Russian. But what else could I do.

In Zywiec (Poland), waiting for my train connection to Zwardon, which is located just at the Polish-Slovakian border.
The train ride to Zwardon was another 1-2 hours, partially nice landscapes and cute small villages. The amount of furniture shops seemed to reduce again to normal levels.

Somewhere halfway between Zywiec and Zwardon in Poland.
The train ended in Zwardon, and then I was faced with the questions on how to get to the village Skalite. A Slovak train was standing ready on the next platform in Zwardon, going to Zilina, however I could not figure out when it was supposed to leave. It was already 15:30, and I was worried it might get dark before I can reach the triplex point, which is another 5 km from Skalite. This would be my only chance to do it, next day I must leave early in order to catch my flight home from Vienna.

Zwardon, just 200 m from Slovakian border.
This brought me into a dilemma, either walk fast those 7 km, (not sure if there is a path all the way), or take the train whenever that leaves. A very friendly Slovakian train conductor was at the site, me trying to communicate in numerous languages with assisted/augmented hand waving. She knew some words in German - "Langsam, bitte!" (same thing I say when someone races off in one of the Slavic languages "Ne bistra!"). A pen and piece of paper did it - train would leave in 30 min.
- "Setzen Sie sich."
- "Ja ja."

View Larger Map

In these small villages there are no places where train tickets can be bought, at least none which are open. Train tickets can instead be bought on the train. I paid 0.48 € for Zwardon - Skalite. On the ~6 km ride, the train stopped 3 times before reaching Skalite. Felt strange.

Arriving at Hotel Kolonial - it was open indeed and I was the only guest it seemed. I quickly checked in, paid 20 € and grabbed my gear for the hike to the tripoint. It was raining cats and dogs, but then quickly cleared.

Skalite. Facing north, Poland is just behind those hills.

One of the countless train stations named Skalite-something. The train stops every 1 km it seems.
The first km you just follow the train tracks to the west. A small tunnel will then take you to the northern side of the road, follow this and you will pass some housing while you leave the train tracks behind you.

Entering Čierne-Polesie‎.
As you exit the village, the road will take you over a small hill and then bring you past a piggery. There might be some signs saying no trespassing, I was not too sure. The gate was open and no one was bothered by my presence. Just after it, you cross a bridge over a small river Čierňanka, and then you are on a marked hiking path. The marks are deceptive though, if you want to reach the tripoint area you must at some point leave the marked path.

You will cross some open terrain and bits of forest, and soon the path follows more or less the Slovak-Polish border. I used the MapDroyd app on my mobile for navigation. Several paths are missing in open street maps, but it is still easy to navigate by just following the general direction.

The crappy GPS antenna of my HTC Desire S was driving me nuts. Could only get a lock in open terrain with no clouds. Got myself a Nexus 4 now. Heaps better, and includes russian GLONASS. Works even inside my flat, so I won't get lost at home any more.
This side: Slovakia. Other side: Poland.
The path took me back to the Polish side. Now outside the forest, I was rewarded with a wonderful view.

Poland, facing north.

Facing east, forest to the right is in Slovakia, everything else is in Poland.

In Poland, facing west. Forest to the left is in Slovakia, the distant hills are in the Czech republic.
Following the path on the Polish side, the actual tripoint area comes into view.

Poland. Hill to the left is in Slovakia. The little roof is already in the Czech republic. 
The area is void of people, but at the tripoint there are facilities to BBQ on either the Czech or Slovak side. Again some monoliths were placed at each country corner, however the actual tripoint is rather hidden.

The Czech and Polish side is on the same side of a small creek which separates Slovakia. A bridge was build where you can cross the creek and go to the Slovakian side.

Here they also got POZORs, beware of them! Do not try to feed them.

Ah! What is that to the right? Is that it? Is that it?! Yes?!

Huh? A cross, not a triangle? What is this? No...?! I got it all wrong!
Where is the real tripoint? In fact, I only realized after I crossed the bridge that something isn't right. There were plenty of these red and white landmark stones scattered around with more or less random marks on, something didn't make sense here.

On the Polish side, seeing the Skovak BBQ place.
The key is the bridge, if you stand on it and look down the western side you may find a small landmark in the middle of the shallow creek.

That's it! Climbing down....

There! The triplex point of Poland, Czech Republic and Slovakia.

Wonder if it can be moved?
In fact, it's kind of a dull place, didn't stay there too long.

Well then... Made it! Primary objective of my central Europe trip completed! :-) From the hotel in Skalite it took me roughly 1-2 hours to get here.


Extensive information on the area is provided by billboards in Polish, Czech ans Slovak.

Trojmezi alright!

Yes, this area is void indeed.

Didn't eat much this day, nearly starving, I could now go back to the hotel (went off the paths a few times on the way back: bad idea, I can assure you). At the hotel, the owner was gone and hotel was locked. My key didn't fit. while waiting, I met a friend of the owner, Fero, (who spoke some German) and a bit later the owner, Karol (who is fluent in Slovak and Polish), came back.

There are no restaurants in Skalite apart of the hotel, and that one is only open at noon. Karol offered to cook me a Schnitzel... perfect! What a Schnitzel! I cant remember I ever enjoyed one so much!

Best Schnitzel I've ever had. Period.
Rest of the evening went hanging out with Fero and Karol. Karol was a virtuoso on the Fujara, a Slovakian didgeridoo kind of thing.

Well... guess I am just as good as playing that instrument as Karol is taking photographs of me playing it. Other way round seems to work better.

Several people (and Slivka) from the neighborhood joined afterwards. Ended up singing a Slovak folk song (the only one I knew - V hlbokej doline - they all tuned in, impressed :-). Made good friends with Fero's son Juraj who took me early next morning to Zilina railway station. From here, the rest of the trip was trivial. I continued to Bratislava where the airport bus took me to Schwechat Vienna airport. Certainly, I got a favorite country in Europe, this place is highly recommended.

Album from the tripoint visit here.

Coming up soon: How to (re)claim small amounts of your country by secretly displacing landmarks in the wilderness.

Update: Lyrics and translation to V hlbokej doline, thanks again, Juraj!
[:V hlbokej doline srnka vodu pije,:]
[:horár na ňu mieri, horár na ňu mieri,
horár na ňu mieri, že si ju zastrelí.:]
[:Nestrieľaj ma horár, neni som ja srnka,:]
[:ale som ja, ale, ale som ja, ale,
ale som ja, ale, zakliata panenka.:]
[:Zakliala ma mamka v nedeľu za rána,:]
[:že som nechcela ísť že som nechcela ísť,
že som nechcela ísť, za pána horára.:]
[:Horári, horári, zle horárujete,:]
[:za každou jedličkou, za každou jedličkou,
za každou jedličkou dievča milujete.:]
[:Horárova žena bledá ako stena:]
[:a horár červený, a horár červený,
a horár červený, ľúbi iné ženy.:]
Approximate translation
In deep valley doe drinks water,
Hunter aims on her,----//----
Hunter aims on her, to shoot her 
Don't shoot me a hunter, I am not a doe
but I am, but i am, but
but I am, cursed young girl. 
My mother cursed me on Sunday morning.
because I didn´t want to marry, ----//----
because I didn´t want to marry, marry with hunter.
hunters, hunters, you are bad hunting
behind every tree,-------//-----------
behind every tree, you are loving a girl. 
hunters wife is pale as a sheet
and hunter is red in face, -----//--------
and hunter is red in face, cause he loves other women.


Sunday, February 17, 2013

The World Did Not End

.. but it was very close!

Meteor trace from 15.Feb.2013, Chelyabinsk. (chelyabinsk.ru)

No, I am not referring to the potential damage a >1 km diameter meteor would have caused.

Instead I thought of the unrelated coincidence that the recent meteor impact near Chelyabinsk happened almost simultaneously when a vagabonding asteroid 2012 DA14 reached Earth closer than the geosynchronous orbit distance.

2012 DA14 passing earth on the 16th February 2013. (nasa.gov)

And indeed these two events are unrelated, which was pointed out by numerous experts in the field.

Now, human minds are put together in such a way, if two very unlikely events happen at the same time, they tend to give it some special meaning, possibly some unphysical, supernatural cause.

This is related to selection bias.

Imagine you have a dream, and a day later it actually comes true. Is this premonition?
No, you just have rejected all the cases where your dream did not come true. Sooner or later you just might get it right.

Think of sampling from a normal distribution, and you have a very small probability to achieve something which is more than 3 sigmas beyond the mean.
Then imagine two normal distributions, the likelihood that you will sample in the extreme tails in both functions the same time, whoho... must be magic when that happens.Yet, these events DO happen, and there is nothing magic about that!

My end of the world scenario looks rather different. Just imagine, the aforementioned events had happened app. 55 days earlier: 21st December 2012.

I imagine mass-hysteria in public, mountains crowed with UFO fanatics, people with tin foil hats roaming the streets, and a surge in people claiming they are Christ the Savior or Buddha themselves.

Some random dude from Wikipedia wearing a tin foil hat. (wikipedia.org)
Now, as a scientist try to explain to a general public that there is no relation between a nearby asteroid, a pretty violent meteor hit, and the end of the Maya calendar.

It would have been the end of the civilization as we know it! A simple series of random cosmic and spritual events happening within a few days, resulting in disintegration of scientific methods and bringing us back to the middle ages. The pope just decided to quit his job, now God is angry (or other way round, whatever). New age fruitcakes, conspiracy freaks and tea party maniacs will go viral and define a new world agenda. Gibberish and nonsense will form new paradigms taught at schools and universities. Creationism, intelligent design, you name it...

What is more likely: a hit by a >1 km diameter meteor, or a hit by a 10 meter meteor, which by chance "collides" with, say, 2 other rare events - inducing a permanent mass hysteria?

Superposition of very unlikely events happen all the time, but by nature they are rare. People work with this professionally in risk management, the trick is here not to make a single rare event be fatal for a critical system. This is what makes flying airplanes safe, today an entire chain of unlikely events have to happen in order to provoke a fatal plane crash.Think of the famous SAS MD-87 crash in Linate:
  • fog, i.e. no visibility
  • missing ground radar
  • missing / ambiguous numbering of taxi ways
  • pilot of Cessna was not certified for landing in visibility below 550 m, i.e. he should not have landed there a few hours ago
if just one of these conditions were not fulfilled, the accident would not have happened. There are heaps of such cases. Another very interesting story which just comes to my mind is how a faulty radiation therapy machine Therac-25 lethally injured several patients due to software errors and other unfortunate circumstances.

Therac-25 radiotherapy unit.
Some recommended scary bed-time reading:

In the end, it's science! Make no mistake.


Friday, July 20, 2012

Last Cereal

This post is dedicated to a wonderful web comic www.lastcereal.com created by Andrea B. Previtera during 1999-2002. I came across it after seeing a review of another comic by same author 10 years ago. Somehow this was effectively saved in my brain, and recently (for whatever reason) it resurfaced - and I was happy to see the website still exists.

The series is sort of autobiographic, or at least pretends to be so. The protagonist, calling himself "H." (very Kafka) lives his life in an anonymous and veritably demonized metropolis.

H. and the city.
The format is classic: 4 images in 321 strips, grouped in four seasons. Strips were created with the windows paintbrush (now: "Paint") program, which inevitably gives the strip a distinct style. The quality and level of detail increases as the series progresses, at some point colors are introduced, but falls back into black and white again. At one point also a few hand drawn strips appear.

The universe is "the city", featuring among others a few friends (of who one is killed), a sadistic job agent, a mysterious sandspire, cryptic figures such as a raging Rastafarian, and most of all a lost love named "M." which keeps recurring, effectively preventing H.'s wounds to heal. The conflict with H.'s love and drug addict M. is mostly treated in the "Silent Serenade of Spirits".

Amazingly few words and a few simple drawn digital brush strokes conveys the conflict effectively and sparked me with emotions. I had similar feelings when reading strips by the danish multi-artist Nikoline Werdelin, in particular her Homo Metropolis series, yet with the notable difference that her work is not as dark or autobiographic and rather pictures the absurdness of society as such.

Last Cereal is a tribute to depression, and when I recently rediscovered the site a few months ago, I realized, it is truely expressionistic. It portraits fears (here partially existential fears), but yet one finds beauty in the misery and plight. In expressionistic paintings you may have a white building in an elsewhere dystopian scenery (Marianne von Werefkin - Die rote Stadt); in expressionistic lyric you find humor which disarms an elsewhere apocalyptic scene (e.g. Georg Trakl - Noch ist Polen nicht verloren), in Last Cereal, this is embodied by the witty dialogues with the psychiatrist H. is visiting.
H's psychiatrist, struggling with his patient.
One of the coolest characters is clearly "Oriental Eyed Man", a notoriously drunk oracle of wisdom. More or less passed out behind a beer bottle, he occasionally gives a blip of concentrated divine insight.

Last Cereal is highly recommended to anyone worshipping miserabalism and anyone who needs a break from happy go lucky narcissistic facebook culture.

The same author also created a comic www.escaped.it, again touching fundamental fears in life. The page, alas, was lost over time in the endless ocean of bytes in the internet. The wayback machine couldn't help either. Hope the author didn't get sued, some of the strips were quite gross.

Author seems to be ok, though, he seems still to be active on a related (but un-linked) forum. Perhaps someone should ask him to fix some of the links.

Just to prevent this mishap again, I made a backup of www.lastcereal.com for my own archives. And surprise... I discovered two un-linked frames: one of the strips has a 5th frame. Another lost frame is related to the Silent Serenade of Spirits, which appears to be dead - but it's not. :-)