The properties of Schott’s borosilicate glass make it ideally suited for constructing neutron guides.
Commissioning has been completed at the China Spallation Neutron Source (CSNS), the country’s first pulsed spallation neutron source, and the fourth in the world. The facility, which has up to 600 metres of guide tubes in 20 beam lines, will provide scientists with a world-leading platform for studies in fields such as materials science and technology, life sciences, new energy and more.
The announcement of completion was made at the CSNS Technology Assessment and Acceptance Meeting, held at the Dongguan Branch of the Institute of High Energy Physics, Chinese Academy of Sciences (IHEP) in the Guangdong Province.
Swiss company SwissNeutronics supplied the research institute with important components made from the special float glass BOROFLOAT® by Schott. The deal is an important milestone for the company, giving them a 60 percent share of the neutron guides market. This is significant, as there are only around 20 research institutes in the world that can even be considered customers.
Building neutron guides requires extreme precision. The BOROFLOAT® supermirror coating only reflects neutrons at very low angles, so if a wall is slanted or not smooth enough the neutrons will penetrate the material, which must be avoided. SwissNeutronics coats the glass with up to 10,000 nano-thin layers. This is where BOROFLOAT® provides the best extremely flat surface.
“Not even individual atoms can project on the insides of neutron guides,” explained Dr Christian Schanzer. COO of SwissNeutronics. “The outstanding properties of this special float glass provide us with a clear competitive edge.”
In addition to the extremely low roughness, the even thickness and high homogeneity are properties that predestine BOROFLOAT® for high-tech applications. Additionally, it offers high chemical and thermal resistance and high mechanical strength. Even abrupt temperature fluctuations do not affect the glass, and it stays true to size even after many work steps. The high boron ratio, which has a shielding effect, is also extremely important, especially for building neutron guides; it practically ‘catches’ neutrons. The low net weight makes BOROFLOAT® excellent to use.
SwissNeutronics has been working with SCHOTT since 1999. At the time the company was formed as a spin-off of the Paul Scherrer Institute in Villigen, Switzerland, to meet the growing demand for neutron guides in research. Float glass was the material of choice from the beginning, but it wasn’t until BOROFLOAT® was utilised that the high standards of research were truly met. The special float glass now serves as a reference substrate for quality assurance at SwissNeutronics.
Dr. Schanzer explained “No other material has this high and consistent quality spanning decades. It therefore provides ideal requirements for improving our coatings. BOROFLOAT® is our opportunity to improve the quality considerably in this respect.”
The microfloat process, a special manufacturing method, is key for the unique properties of BOROFLOAT®. Glass ribbons float over of a bath of molten tin to then cool down. This patented process guarantees perfect homogeneity, extreme flatness and a mirror-like surface. The high optical quality comes from a special “secret recipe” and is still unrivalled in the field of flat glass.