Vacuum Technology Department
The Vacuum Technology Department of Institute of Modern Physics (IMP) is responsible for design, operation and maintenance of the vacuum system of Heavy Ion Research Facility in Lanzhou (HIRFL) . There are 16 employees, includes one professor, 3 senior engineers, 7 engineers, and 2 graduate students.
The vacuum system of HIRFL consists of a sector focus cyclotron (SFC), a separate sector cyclotron (SSC) , a multi-purpose cooling storage ring （HIRFL-CSR） and dozens beam lines. According to the requirements of the ion acceleration and ion lifetime, the working pressure in SFC, SSC and most beam lines is 10-5Pa~10-6Pa. However, to minimize the beam loss due to charge exchange of very heavy ions with the residual gas molecules, the working pressure of lower than 10-9Pa is required for HIRFL-CSR.
By technology innovation and integration, a set of UHV and XHV obtainning techniques was formed. With the techniques, an average pressure of 5´10-10Pa was obtained, which is the lowest pressure in a large vacuum system in China and is the best result which can be obtained at the accelerators in the world as well. 2 inventive patents and 6 other patents were achieved during the development.
Our research is mainly the development of UHV/XHV obtained techniques, which include the research for materials used in vacuum system, the material treatment technics, reducing the outgassing rate of the materials in large amount with lower cost, characteristic of pumping system with a optimum combination, measure methods for total and partial pressures and the calibration for the measure gauges and the research for design, manufacture, welding, leak detecting of various vacuum chambers.
In the research of the vacuum equipment, some clean and oil-free pumps were developed, such as a new type of titanium sublimation pump with high pumping speed, long life-time and low cost; a new type of sputter ion pump with low outgassing rate, high pumping speed and low ultimate pressure. Make use of DC magnetron sputtering coating technology, the TiZrV filmswerecoated in the inner surface of vacuum pipes. It could translate the vacuum pipes from gas load into pipeline pumps with a even distributed pumping speed. Both pressure distribution and ultimate pressure in thin and long vecuum chambers will be improved in this way. At the same time, the development and production of the vacuum bake-out jackets, bake-out control devices, large and complex brazed ceramic pipes are carried out.
In our laboratory, there are experimental devices with the pressure of 10-10Pa, in which various experiments in an UHV and XHV conditions can be done. The pumping speed and ultimate pressure test devices for various pumps, material outgassing rate test device and vacuum gauge calibration device all are established in our laboratoty. We have 5 leak detectors with a high sensitive of 10-9Pa.l/s. 2 large vacuum furnaces can be used to degas vacuum chambers and braze ceramic pipes.
Our research production can be used in the fields of accelerators, basis and application research for nuclear physics, navigation and spaceflight, semiconductor industry, medication, environment protection, new material research and so on.