Data Analysis and Results of the Proton Scattering Experiments

Abstract

In order to extract the absolute cross section of each state from the measured raw data a series of analysis steps have to be taken. First of all, the scattered protons are identified using the $\Delta E$ information of the two plastic scintillators on the focal plane and a time-of-flight (TOF) measurement (Sect. 7.1). Secondly, the position and angle information of the protons passing through the focal plane are determined using the three vertical drift chambers (VDCs). This involves setting up a suitable lookup table to convert drift times to drift distances (Sects. 7.2.2 and 7.2.3), a definition of what is considered as a valid event, an algorithm to determine the position from the drift distances and finally to calculate the horizontal and vertical positions and the horizontal scattering angle on the focal plane (Sect. 7.2). Before calibrating the horizontal position—which is related to the momentum of the proton—it is necessary to calibrate the horizontal scattering angle at the target position using the sieve slit data (Sect. 7.3) and to correct for the aberrations of the spectrometer and the kinematic dependence of the proton momentum on the scattering angle (Sect. 7.4). The energy calibration procedure is outlined in Sect. 7.5. Finally the absolute cross sections are determined (Sect. 7.7).