As described in Section 3.4.3, the MWPC system determines the position of the electron hit from the delay times, the time it takes the signal to reach both ends of the delay line (see Eq. 3.4). In addition to a hardware discrimination (via pre-amplifier threshold) against noise in the delay signal lines, the following off-line software cut procedure was applied in order to ensure the quality of imaging.
Since the delay lines have a fixed length, the sum of the delay times is expected to be constant, i.e., for the Z-direction, , where ZL and ZH are the delay time measured at beam upstream and downstream ends of the delay lines, respectively, and the sum is multiplied by the dispersion constant, dispZ with a length dimension for convenience. In reality, however, a small but finite amount of time is required between the ionizing electron and the current being induced in the cathode wires, mainly due to the drift time of electrons to the anode, which creates a distribution in SUMZ (and ) reflecting the proximity of the initial hit to the anode. There is a strong correlation between distributions of SUMZ and SUMY, since they are due to the same physical process for both z and y wires, i.e., electron drift to the
In this chapter, we present the analysis of Run Series I, in which the emission of muonic tritium is studied. The first section deals with the treatment of the MWPC imaging data, and in the second section we present a quantitative analysis using detailed Monte Carlo calculations.