In Soviet times, science developed at an incredible pace. One discovery was followed by another, no less significant. And human craving and greed for knowledge only grew along with this. So in our country there was an uncountable number of scientific research institutes - Scientific Research Institutes. Some of them function to this day, some have long been wiped off the face of the earth, and some have been left to fend for themselves along with all the equipment.
Today we are not talking about the research institute itself, since it clearly does not belong to the abandoned ones, but about the once functioning laboratory under this research institute. And not just under it, but at a depth of 45 meters!

Depth of occurrence: - 45 meters
Research Type: Nuclear Physics

First, let's figure out how it all looks. There is a certain building that you can get into. In the basement of this building there is an inconspicuous wooden door, and behind it - 45 meters of a human walk under the ground. This is how it looks schematically (proportions preserved):

The place itself is unique in itself, since in our time such deep laboratories can be counted on one hand. Unlike the research institutes themselves, there are really very few of them. I know of only 3 such laboratories, including this one (which have no connection with the subway). And even if there are other deep laboratories, it is unrealistically difficult to find them! The reasons for this: the scientific race and the spirit of the Soviet secret. In the days of the USSR, structures of such depth were built under the heading "secret", and any signs that a laboratory was underground were carefully masked, or they were not at all. For example, these structures did not have any ventilation system, and the trunk in such laboratories was located in the basement of the building so that the building itself “disguises” the laboratory. Therefore, the function of the building, passed off as valid, as a rule, differs from its real function by an order of magnitude. Moreover, in practice, there was a case when the floor opened in a seemingly ordinary shed "exposed" under itself numerous spans of a human walker in the trunk.

So, how everything happened:

Three people of different physique once again cast a disdainful glance at the small building in front of them.

"Are you sure you're here?"
- The fact of the matter is that I'm not sure! I just assumed she was there. Do you know how many research institutes there are in Moscow ?!

There are really a lot of research institutes in Moscow, but the choice fell on this one. The three stood close to each other and looked through the window at the main hall. It was promising: a middle-aged man would appear in front of the front door every now and then, pass by, dissolve somewhere in the corridor. The main thing, we thought, was to get on the stairs. And so that they would not notice us. The rest will happen by itself.
We decided to wait until the people in the building lay down to sleep. Midnight. Hour of the night. Two o'clock in the morning. Three…
At three o'clock in the morning, music began to play in the building of the institute.

- Are they crazy?
- Why are these scientists still awake ?!

At four o'clock in the morning everything settled down, the lights went out. It was decided to act.
And now three are already climbing onto the roof through which it was planned to get inside. A couple of dexterous movements, and they are already inside the building. All that remains is to go down to the basement.

The shaft is located in the basement of the building (a tunnel extending vertically down to a depth of about 45 meters, where the laboratory block is located).

The construction was carried out by the metro building back in the 45s. First, the trunk itself was dug, after which they dug the laboratory block and strengthened it with tubing.

In due time, we can only go down.
As you descend, you feel that the laboratory is really abandoned. New, freshly painted staircases are replaced by old rusted ones. The walls are cracking, traces of groundwater are visible.

On the left side, behind the grid, there is an elevator shaft. It would be much more pleasant and convenient to go down to the laboratory by elevator, but we decided not to irritate people from above. And rightly so, because when our small company had almost reached the bottom of the trunk, dull footsteps and voices could be heard from above.

On the left is the staircase, on the right are the doors of that same elevator. Behind the back there are wooden double doors, behind which is the laboratory block itself.
And here he is:

The dressing room.

Back view from the dressing room, towards the wooden doors:

We leave the dressing room in the main room:

Half of the premises here are occupied by electrical equipment (in particular, switchboards, lighting) and drainage - pumping systems for pumping out groundwater, which are the eternal problem of such structures.

The other half, as it might seem at first glance, is occupied by an absolutely useless frame made of metal beams welded together.
In fact, this construction carries a certain meaning.

I answer the question: "So what did Soviet scientists do at a depth of 45 meters underground?" - Nuclear physics of cosmic rays. Specifically, by examining their spectrum.
To be honest, it is hard for me, as a person far from physics, to imagine how a beam of cosmic energy passes through a building, then through a 45-meter layer of rock and, reaching the target, disintegrates into something there, but apparently this really happened ...
Metal beams here serve as "shelves" for briquettes of lead and iron, passing through which the radiation beam is transformed into something there.
Scientists call all this clever design "Ionization calorimeter"

Scheme of an ionization calorimeter in combination with nuclear photoemulsions:

1 - a target in which the interaction of a cosmic particle with nuclei occurs, leading to the appearance of high-energy g-quanta.
2 - layers of lead, in which g-radiation generates electron-photon cascades.
3 - photographic emulsions recording tracks of charged particles.
4 - layers of iron that inhibit charged particles.
5 - pulse ionization chambers.

You can familiarize yourself with high-energy physics in more detail on thematic resources, and we will continue our walk.
If you do not look closely, it does not strike the eye how many briquettes of metals are in the laboratory's stock. But let's take a closer look - they are everywhere.
Red, in front of the calorimeter - this is not a tile. On the left - the same. The briquettes also lie in several layers on the shelves of the calorimeter. There are really a LOT of them.

Behind the wall of the main room there is a continuation of the block, a small room where ventilation from the surface is diverted, as well as in which there was a computer.

On the left is a piece of the ventilation hood, on the right is the casing of the block.

Let's go back to the main room of the laboratory and go straight to the calorimeter. Where the target should be.

We stayed in the laboratory for several hours, the final shot and we are heading for the exit.

When we got out of the laboratory, it was about 6 in the morning, it was just getting light. It was raining outside. A very unusual feeling when you spend a lot of time deep underground and then get out to the surface. For some reason, from all over the trip to this laboratory, I especially remembered exactly how it was drizzling when we finally got out. Contemplating drops through the twilight gloom, our modest team headed towards the eternal fire to warm up and wait out the rain.

PS: there are completely incomprehensible people in the building upstairs. As far as I know, the building itself was built for complex work with the laboratory, now scientific activity is also being carried out there, but rather sluggish.
However, this does not prevent employees from going to bed on Saturday night to Sunday at 4 am and getting up at 6 am. Turn on loud music, so that it reaches the laboratory and find harmony with science ...

Thanks for your interest in my posts!