ИСТИНА

The constant increase in mass of the cryostats, containment tanks, passive shielding and other mechanical elements of the modern low background detectors put more stringent requirements on their radiopurity levels of the construction material. In general they have to be ~1 mBq/kg of 238U / 232Th or lower, which means that mass concentration should be < 0.1 ppb for 238U and < 0.25 ppb for 232Th. Traditionally, the field relies on specially selected low background stainless steel, electrochemical oxygen-free copper, or a combination of the two. However, the most promising material in terms of physical and mechanical properties is Titanium. Our study of various Ti samples and Ti-containing products show that the levels of contaminations of commercially available industrial titanium can varies from 0.2 to 100 mBq/kg for U/Th. By the way, we offer the approach when the preselecting of the input products together with specially improved production cycle and special physical-chemical treatment of the resulted material will give us ultrapure titanium ready for the following mechanical processing.