Water Cooled Flange

Introduction: Water cooled flanges are installed at the SR beam ports of dipole chambers for dumping the synchrotron radiation during commissioning  of the Storage Ring, temporarily for 27 beam line ports   and permanently for 21 unused ports. There are total 48 water cooled beam dump flanges installed across the ring on 16 dipole chambers. There are total 3 numbers of water cooled flanges mounted on 0°, 5° and10° ports of each dipole chambers.  Approximately 30 kW of SR power is absorbed by these flanges. SR power density on these flanges is ~ 1.2 kW/cm2.

Design  & Fabrication: Salient design features of the water cooled beam dump flanges are: heterogeneous compact structure of OFHC copper central portion and outer stainless steel flange, leak proof isolation of water line  to vacuum joints, UHV compatibility, vacuum brazed joints, rectangular finned type water channels for enhanced heat transfer, inclined face incidence of photons facilitating substantial decrease in heat flux density etc. It is a three piece construction of OFHC copper and Stainless Steel. Inlet and outlet water cooling copper tubes are projecting out of the flanges.

Fabrication of water cooled flanges crotches involves various stages like, CNC profile machining of brazed components, EDM wire cutting of  brazing foils,  vacuum furnace brazing, quality assurance etc. In order to get bright, oxide free, degassed and UHV compatible leak tight assembly, vacuum furnace brazing was used to braze the entire assembly of water cooled flanges. Entire assembly was brazed in single stage.
Helium tuned mass spectrometer leak detection (MSLD) was done for all the WC flanges before leading to ultimate vacuum testing. Leak tightness achieved is <2 x 10-10 std cc/sec.
After baking at 150° C for 8 hrs, ultimate vacuum achieved is ~ 2 x 10-10 mbar with the help of  SIP (140 l/s). Sectional view of a typical water-cooled flange is shown below.

Water cooled flange