Gold beam losses at the AGS Booster injection

Gold beam injection efficiency decreases in proportional to the beam loss in the AGS Booster. A close look shows that large number of electrons, ions, and neutral particles are created when the gold beam scrapes wall. To investigate the neutral particle production due to the beam loss, local vacuum measurement was made during the 1998 run. It shows that the pressure created by the Booster Au/sup 31+/ beam loss at injection has a 35 ms decay time constant. The beam loss created pressure bump in the ring is about 20 meters long. When 3/spl times/10/sup 9/ gold ions scrapes wall, a pressure higher than 10/sup -7/ Torr was created. The beam lifetime calculated using these parameters is in agreement with the observed one.