The experience of fluoroscopy at home

At one time, I had accumulated a sufficient number of cool, but nonetheless useless things in everyday life, one of which was a tube for X-ray analysis "BSV-25".



Massive fool, water-cooled, 60kV anode, 300 watts of dissipated power and four beryllium windows for radiation output from each side.

And she would have been gathering dust on a shelf for a long time if it had not come to my bright mind that an almost suicidal thought was to launch it. As the source of the anode, I decided to use the good-old line transformer from my grandfather's TV, pumped by the generator on a 6p45s lamp:



At the output, we get 12-15 kV, with a frequency of 20 kHz.



Next came the question of the voltage multiplier. The fact is that this lamp with a massive anode. And it should be connected by supplying a negative voltage to the cathode and grounding the anode. A glow transformer must withstand a potential difference of 60 kV on the primary and secondary windings.

Naturally, the prospect of manufacturing and pouring a multiplier with a negative "hot end" with epoxy resin, and even manufacturing a second generator with ferrite from the line driver, in order to throw 3-4 turns of BB wire on it and feed the glow, did not please me at all. Moreover, I didn’t try to swing the lamp to its full power, therefore, there was no need for water cooling for the anode.

But if you started breaking grandfather’s televisions, it’s hard to stop. And I decided to use three “un9 / 27-1.3” multipliers, connecting them in series.

To be able to connect them in series, two multipliers had to be cut with a hacksaw, finding the so-called “output A”, and connected through a 30kV 470Pf capacitor to the input of the next multiplier.



The finished structure was mounted on a piece of textolite, and all joints and sawn outputs “A” were varnished in order to avoid the occurrence of corona discharges.



This multiplier made it possible to obtain 80-85 kV.
Then the question arose of a phosphor glowing in x-rays. Searches led me to a chemist store where they sold anthracene, but alas, they sold it in packs of a kilogram, and since I didn’t plan to eat it for lunch, breakfast and dinner, this option was dropped. When I threw a cry for acquaintances in search of a subject, one of them responded and gave me a bag of some light green substance for a bottle of beer. It seems like this phosphor covered the bottom of the oscilloscope picture tubes.

The first time I started the lamp, I simply poured an even layer in front of one of the phosphor windows, laid the remaining three windows with pieces of lead, and the lamp itself stood as an anode on linoleum. I put an additional casing of 1.5 mm steel at the back, I didn’t think about reflected beams then. For photofixation, I put the camera on a tripod and extended usb wire from it to the laptop. Itself was located behind a casing, 5 meters away with a laboratory power supply unit, which regulated the filament voltage (when supplying a standard 3V filament to the lamp, the emission was too large and the voltage on the multiplier sank almost to zero):



And it worked! One of the images showed a clearly visible spot of the radiation beam.

Later I took a piece of cardboard, sprinkled a thin layer of phosphor on it, fixed it with strips of adhesive tape, getting a simple screen. By placing various objects in front of the screen, they managed to enlighten them through and get a fairly clear image on the screen.

About security

So - this is a damn dangerous thing, the radiation in the beam at a distance of 30-40 mm from the exit window reaches about 500 r / h. Despite the fact that at an anode voltage of 60 kV this is a “soft” X-ray, and even a 2 mm sheet of metal delays it almost completely, not to mention the J \ B floors of the house, and there is no induced radiation from X-ray radiation, nevertheless even the reflected radiation in the room is enough to spoil your health. With direct beam irradiation, you will find joys such as acute radiation sickness and radiation burns to your arms, legs, or how you get there under the beam. In general, for completely safe operation of the structure, it needs to build a sealed lead “house”, and for this it is necessary to make a normal source of negative anode voltage so that it is possible to ground the anode. Or take a separate room for her, driving her from another room. Without this, the operation of the installation without harm to health is, in principle, impossible. Since I collected it out of interest "is it possible", then in the future it never again started, and the lamp went to its place on the shelf, in the form of an exhibit of the EEC collection.

To the question of the consequences on my personal health.

The installation worked for a total of 10 minutes, the dose accumulated by me was not measured in any way (which is a fail and another gross violation of PTB). After 20-30 minutes, when I turned it off, there was a feeling of slight nausea (like after a heavy load on the vestibular apparatus on all kinds of “vomitron-3000” carousels), which passed after a couple of hours. Three days later, the temperature rose to 37.2-37.5, and so it stayed for a week, it was not possible to take it off medically, a week later itself passed. I started the installation from a year ago and there were no more symptoms.