Systematic Check of Blowfish Neutron Detector for GDH Experiment: With an Emphasis on Gain Calibration

Abstract

The University of Saskatchewan subatomic physics group, along with collaborators from the University of Virginia, Duke University and others, are preparing to measure the low-energy regime of the Gerasimov-Drell-Hearn (GDH) sum rule for the deuteron. This sum rule connects an energy weighted integral of spin-polarized photo-absorption cross sections with the anomalous magnetic moment of the target. It is based on the gauge and Lorentz invariance, and the general principles of causality and unitarity. The measurements made for the GDH sum rule will use the Blowfish neutron detector to detect the neutrons following the deuteron photodisintegration. The GDH sum depends on the difference between absolute cross sections. It is therefore critical to the success of the measurement that systematic uncertainties, in the determination of the absolute cross sections, are understood. This MSc thesis will include a thorough investigation of the systematic uncertainties in the measurement. This will include: verification of the gain monitoring system for the Blowfish neutron detector cells; verification of the photon flux monitor; and the calibration of that system.