Processing and evaluation of the AGS booster ultra-high vacuum system

The Alternating Gradient Synchrotron (AGS) Booster is a synchrotron for the acceleration of both protons and heavy ions. To minimize the beam loss due to charge exchange of the partially stripped, low beta , very heavy ions with the residual gas molecules, a pressure of low 10/sup -11/ Torr is required for the 200 m booster ring. To achieve this, ultra-high-vacuum, chemical cleaning, vacuum furnace degassing, and in situ bake were employed for all chamber and beam components. Using these procedures, vacuums of low 10/sup -11/ Torr have been routinely achieved during the testing of individual half cells and beam components, and during the commissioning of the vacuum sectors. The design and layout of chambers, flanges, and bakeout hardware are briefly described here. The vacuum processing of different components and the results of bakeout and evaluation are summarized. The experience gained during the construction and commissioning of this ultra-high vacuum system is also described. >