Bawwwww

@cjsavvy: permanent semi on one side, it would curve like a banana to the burnt side. Luckily we have proof at wiki.

Goes to show you how things can go horribly, horribly wrong with just a moment's carelessness.

You're assuming that he was perceiving that visual phenomenon with his eyes. Why? A large dose of magnetism or radiation to the brain can stimulate the visual cortex, and he was probably perceiving that, not an actual visible light.

"Then the description of the”path of the beam” seems more like a description of science fiction."

I assure you it's not. There's a defined path along which a particle accelerator accelerates the beam of protons (or other particles), and that phrase is not inaccurate.

"Then “the insides of his head continued to burn” for another two years is either inaccurately stated or is another attempt at science fictioning."

You're making a lot of assumptions that are not supported by biology or medicine. The effects of radiation exposure can indeed continue for some years after exposure, as cells accumulate genetic damage, fail to reproduce, or are functionally impaired. In particular, I'm familiar with cutaneous radiation syndrome, the effects of which can continue for a good while.

Light "brighter than a thousand suns" should have caused severe actinic retinitis to have blinded him permanently.

Then the description of the"path of the beam" seems more like a description of science fiction.

Then "the insides of his head continued to burn" for another two years is either inaccurately stated or is another attempt at science fictioning.

Finally the site of paralysis is on the wrong side.

Now, I could very easily be totally wrong about this, so don't flame me for trying to pass myself off as an expert, because I'm not. I'm just trying to combine what's already been said in the comments.

FYI, beam energy can be measured in syncrotrons by detecting the frequency (number of times proton bucket is flying around the ring per second) and beam position within the beam pipe, to figure out the trajectory length of the bucket. Simple (quantum mechanics) math would than produce beam energy as accelerated.

The same article claims however, that the radiation he received was 200 000 rentgen at entrance and 300 000 rentgen at exit. Not sure how it ranslations to radiation dose in Gy. I agree, the dose of 5-6 Gy localized is not lethal.

Another thing is like Semi said a proton beam would have to be very slow to only be the speed of sound. Speed of light would be more accurate.

As an answer to your question Sasha, the exact energy of the beam is determined by the amount of Voltage applied to create the beam in the first place, which is manually controlled and documented by who ever was running the machine.

http://www.tpp89.ru/metropol/Personalnyi_cernobyl_anatoliy_bugorskogo. html

is a link to the Russian version of the story where some facts are provided (although some inconsistencies exist there as well)

In this case, the beam was deflected into a small branch for experiments in air (not in vacuum). The previous experiment was not at a high dose, therefore, according to the article, the door interlocks were turned off. (NOTE: door interlocks - are mechanisms that detected when the door is opened and shut off all system that are needed to systain beam in that branch). The warning lights were not flashing because a light bulb burned out. Anatoli called accelerator control to disable beam on that beamline in 5 minutes, but arrived a bit early. Lights were not flashing indicating the beam has been shutoff. Door interlocks were bypassed, so he entered the room. and bend down to check his equipment?

The beam was pencil-sharp (2.3 mm - diameter) and entered the back of the skull exiting around left front nostril. Lucky for him it did not go through any critical organs and was probably of a high energy, which also helped him not depositing all of its energy at the Bragg Peak. (Official quote from his medical records and handicap ID are provided in the article). He felt it immediately but, finished his job, made an entry in the log and went home. In the morning, he went to the hospital with a swollen side of the face. He is fully recovered (except for seizures) and has small spots on entrance and exit of the beam. It is unclear, though probably using the very chamber (dosimeter) he was working on, how do they know the precise dose deposited into him?
Another question: what was the energy of proton beam? At 70 MeV, the depth of the Bragg Peak (a spot where all protons release their energy) is at about 3cm. At 250, it is located at around 30cm deep in water equivalent. In other words, if the energy of the protons was higher than 250 MeV, most of the particles would just fly through his head with very little interactions. Anything less, the entire energy would be deposited somewhere inside his head.

People who understand neither particle accelerators nor proton beams probably shouldn't be commenting so enthusiastically.