Spark-chamber labelling of tracks in a bubble chamber

Abstract

A method of studying the interaction of high energy particles of particular masses in a bubble chamber when exposed in an unseparated beam was devised and experimentally tested. It is based on the labeling of bubblechamber tracks with the aid of a sPark chamber controlled by a particle-selecting counter telescope. By correlating the positions in the spark chamber with those in the bubble chamber, the tracks of the selected particles may be indicated, which permits study of the interaction of these particles in the bubble chamber or their exclusion as an undesired contaminant of the beam. Several particles may be labeled in each bubble-chamber photograph. A preliminary experiment for labeling 5-Bev/c K- tracks in the 20-in. BNL hydrogen bubble chamber is described. The accuracy with which the track position in the bubble chamber was determined was approximately plus or minus 3 to 4 mm in this case; however, it can be improved to approximately plus or minus 1 mm. Methods used in correlating spark position with bubble-chamber track position are presented, and means of improving the precision and the efficiency of scanning and analysis are discussed. The technique may be applied in beams at momenta up to approximately 200 Bev/c,more » as it is limited only by the particle-selecting counter system. (auth)« less