HIRFL真空系統2008年現狀
According to the requirement s of commissioning and experiments , the vacuum systems of SFC, SSC, beam lines and four subsystems of CSR opened to the air for more than 40 times in 2008. The vacuum degree renewed to the required target rapidly every time. Even if for the CSR vacuum chambers which needto be bakedout , only 3～5 days were needed to get the pressure from atmosp uere down to 10 - 8 Pa.In 2008 , about 20 old vacuum gauge sensors were changed to improve t he measure precision. Themeasure datas were sent to the center control room by network. It is convenient to monitor the workingpressure in every part .
Fig. 1 XHV section of the beam line.
All vacuum component s of the heavy ion cancer therapy beam line have been finished and installed insite (Fig. 1) . With different vacuum obtaining procedures , the pressure of 8×10 -10 and 1 ×10 - 6 Pa wereachieved in XHV section and UHV section respectively. The pressure transition f rom XHV to UHV wassmooth and the pressure of CSRm of 10 -10 Pa was not affected at all . Both the ult rathin stainless steelt ube and the ceramic tube ( Fig. 2) were developed for t he high frequency scanning magnets to eliminate theeddy current . The windows wit h the sizes of 200 mm×200 mm were made in Germany ( Pink company) .The Hostap han plastic film and the Kevlar fiber were use toget her as t he window materials to withstandt he atmo sphere pressure and wit hout neut ron produced.
Fig. 2 the ult ra2thin stainless steel tube and the ceramic tube.
The vacuum system of t he heavy ion microbeam facility was built in 2008. Some shockp roof measureshave to be taken for the system to meet the requirement of the microbeam. The vibration of the pipes waslower than 2 m during the turbo molecular pump soperating.
