Students of the Faculty of Radiophysics are optimizing the technology for producing X-ray radiation sensors based on gallium arsenide compensated by chromium, which is used in the work of the Large Hadron Collider at CERN. This project was judged the best at the all-Russian competition of scientific and technical creativity of youth STTY-2017 in the category New Materials and Chemical Technologies.
The team of students included Leila Shaimerdenova, Ivan Shcherbakov, and Irina Kolesnikova. They work under the guidance of Professor Oleg Tolbanov at the Laboratory of Functional Electronics. The technology of compensation of gallium arsenide by chromium that they performed is a unique development by TSU.
- The power of X-ray sources is growing, so the requirements for the efficiency of detection and the stability of detectors, as well as the ability to work at high intensity of ionizing radiation, have become tougher. Therefore, it is important to develop sensors that meet these needs, - says Leila Shaimerdenova.
Today, ionizing radiation detectors are mainly based on silicon and cadmium telluride. However, silicon is not able to work at high radiation intensities, and cadmium telluride sensors are less efficient and more expensive.
- Our sensors based on gallium arsenide compensated with chromium register each quantum separately and distribute information on energy and coordinates, - explains Leila Shaimerdenova. - Therefore, you can get a color image of objects of different density. For example, in medicine these are images of bones, soft tissues, and blood vessels.
Students optimize the process of creating sensors. For this, they conducted a series of experiments to determine the main parameters: the efficiency of charge collection, specific electrical resistance, the level of dark current, and the distribution of the electrical field strength. As a result, it was possible to determine the parameters for optimizing the technology.
Sensors based on gallium arsenide can be used in medicine, cargo inspection systems at airports, railway stations, and on highways, as well as in high energy physics research. At the moment, an experiment is under way to recreate the Big Bang (the ATLAS project), which contributed to the formation of the universe. The registration of this phenomenon is carried out with the help of Tomsk detectors based on gallium arsenide compensated by chromium.