Internal image of the Xi'an Circumvallation captured by the muon imaging detector. (PHOTO: JOURNAL OF APPLIED PHYSICS )

By TANG Zhexiao

Developed by researchers from Lanzhou University, muon imaging technology has recently been applied in cultural relics of the Xi'an Circumvallation recently.

Built between 1370 and 1378 in Ming Dynasty, the Xi'an Circumvallation is one of the oldest, largest and best preserved Chinese city walls. After hundreds of years, the wall has partially collapsed and subsided, posing great challenges to archaeological examination techniques.

Conventional techniques sometimes could destroy the structure of the target object, which hampers conditions for internal detection of cultural relics and historic sites.

As an elementary particle similar to the electron, the muon has extremely strong penetrating abilities, and can realize non-contact and non-destructive imaging of large targets, which is quite advantageous compared with conventional artificial ray devices, according to the researchers.

Based on muon imaging technology, the team developed a set of high-precision device, which can accurately and safely conduct internal detection and restoration of large-scale cultural relics and historical sites.

In the examination of the Xi'an Ming Circumvallation, the position, shape and size of the anomalies inside the wall have been clearly presented with the help of the device.

This technology also has broad application prospects in glacier scientific research, landslide monitoring and searching for smuggled nuclear materials at customs borders control.