Nuclear Physics in Search of World Artifacts: The First 3D Images of the Oldest Christian Church in Russia Were Obtained

NUST MISIS scientists together with the colleagues from P.N. Lebedev Physical Institute of the Russian Academy of Sciences of the Russian Academy of Sciences, Skobeltsyn Institute of Nuclear Physics Lomonosov Moscow State University and Dagestan State University have published the first results of a “scan” obtained by the method of muon radiography of the underground space in the Derbent fortress of Naryn-Kala. The preliminary conclusion of the scientists — the hypothesis of archaeologists about the use of the building as a Christian temple is most likely to be true. If this theory is confirmed, this building is one of the oldest churches in the world.

The 12-meter building is almost completely hidden under the ground, only a fragment of a half-destroyed dome is visible above the surface. This building in the northwestern part of the Naryn-Kala fortress in Derbent dates back to about 300 A.D. To date, the issue of the function of the building has not been resolved: a reservoir, a Christian temple, or a Zoroastrian fire temple. If this is really a Christian temple, then we can talk about the oldest in the country and one of the oldest in the world Christian churches, which was covered with soil by Arabs after the capture of Derbent in about 700 A.D.

It is not possible for archaeologists to come to a consensus because the excavations of the temple, used for two centuries as a reservoir, can destroy a UNESCO cultural heritage site. Therefore, to study the premises, scientists used the method of muon radiography, placing several innovative detectors with a nuclear emulsion inside a buried building at a depth of 10 meters from the surface of the earth. The research lasted from May to September 2018, the first data obtained confirmed the effectiveness of the method for the study of this specific object.

The purpose of the experiment was to find out the possibility of studying the selected archaeological object using muon radiography, determine the optimal exposure, the number, size, and location of the detectors, get the first images of the object using nuclear emulsions. The results obtained from the muon detector made it possible to confirm the reliability of the study of the building using muon radiography (which was not obvious given the similar density of soil around the building and the shell-limestone walls) and suggest a plan for a full-scale experiment to identify the contours of the building as a whole.

In addition, already in the first test experiment, physicists “saw” an unusual distribution of muon fluxes in the western wing of the building, which may be related to the architectural features, indistinguishable by fragments of walls located above ground. The construction, built of local shell-limestone, is about 11 meters high and extends 15 meters from south to north and 13.4 meters from west to east. Segments (arm) of a cruciform design have a width of about 5 meters, three arms of a length of about 4.2 m, and the fourth (northern) — more than 6 meters. The brackets are covered with vaults, and a dome wire frame with a diameter of 5 meters is located above the central part.