Speaker
Description
Currently, one of the most significant areas of research in physics is the search for neutrinoless double beta decay. To conduct such studies, it is necessary to minimize the level of the radioactive background of the experiment. The selection of the purest structural materials is necessary, since the achieved background level determines the final sensitivity of the experiment to the studied physical processes. This is achieved through various methods, including placing installations in underground laboratories, carefully selecting structural materials, and using active background suppression techniques. However, the new generation of experiments require an even lower level of natural radioactive background. Both the detector itself and its surrounding shield elements contain background sources that are unavoidable. Therefore, it is not only important to look for new materials with lower backgrounds, but also to ensure that there is no radioactive contamination during the production and processing of parts. At present, 3D printing technology has become widely used. The use of this technology can avoid the need for mechanical processing of manufactured parts, preventing potential additional contamination during the manufacturing process, reducing its duration, and reducing the number of steps required for final cleaning before installing the parts. 3D printing allows for the creation of complex structural elements with acceptable mechanical strength using a small
amount of material, and manufacturing parts in a shorter time.
We have studied the possibility of using 3D printing to create structural elements of low-background detectors and low-background shields. The materials used for 3D printing were studied using low-background semiconductor gamma-ray spectrometers at the Baksan Neutrino Observatory of the INR RAS in order to measure the activity of radioactive impurities in these materials. These measurements made it possible to select the purest samples of filaments for 3D printing, which were subsequently used in the development and printing of the body of the test scintillation detector.
Test calibration measurements were carried out using a scintillation detector with a body printed on a 3D printer in order to verify the possibility of using 3D printing to create structural elements of detectors. We have printed the body of a scintillation detector with a volume of 100 cm3. A scintillation detector was manufactured using a LAB-based scintillator with the additives PPO (2 g/L) and Bis-MSB (0.02 g/L), which was filled into a printed case. The volume of the detector was viewed using the PMT-97. To verify the functionality of the experimental setup, a series of measurements were carried out using calibration sources $^{137}$Cs and $^{60}$Co. The background spectrum was collected over a period of 16 hours at the Laboratory Building of the BNO INR RAS. The results obtained confirmed the feasibility of using 3D printing for manufacturing structural elements of detectors. In the next stage, to avoid possible contamination of the samples during printing by $^{222}$Rn daughter products or other radioactive isotopes that may be present in the air, we plan to place the printer in a dust-free area of the low-background, deep-laying laboratory at the BNO INR RAS. It is planned to additionally place it in a special protective casing surrounding the 3D printer, in which a nitrogen (or argon) atmosphere will be created.
This study was supported within the State contract of the Ministry of Science and Higher Education of the Russian Federation no. FZZR-2022-0004.
