Development of the CHICSi multi detector system and experiments with its auxiliary systems

Abstract: Two new detector systems are described, including several new detector concepts. They areintended for use in heavy ion reaction experiments at the CELSIUS storage ring of the TheSvedberg Laboratory in Uppsala. In addition, results of experiments are presented, togetherwith theoretical calculations.The CHICSi multi detector system consists of around 1750 detectors, mounted in a barrellike structure. Integrated electronic circuits are used for handling the electronic signalsalready inside the ultra high vacuum scattering chamber. CHICSi will be used for detection ofintermediate mass fragments with a high solid angle coverage. This work describes thesimulations and development done in order to achieve the desired detection properties, as wellas measurements for understanding the response function of the system.An integrated δ-E silicon detector could make future experiments, like CHICSi, more compact and less vulnerable. A prototype of such a detector is presented. Measurementsindicate that most properties are better than for any now commercially available detector. Residues from heavy ion reactions carry important information about the reaction process.However, due to their large mass and low velocity, they are difficult to detect. A time-of-flight telescope was developed for this purpose, with which residues were detected in 25A -400A MeV 14N, 16O and 20Ne on Ar, Kr and Xe reactions. The obtained residue velocities and linear momentum transfers at high beam energy are higher than observed in similar reactions that lead to fission. The telescope response was measured and analyzed.Pion production experiments were performed. The special. ramping mode of the CELSlUSring was used to extract excitation functions for positive and negative pions. There isreasonable agreement with BUU and QMD calculations. The measurement did not reveal anysign of a δ-ball resonance, which was predicted by some theories.