Event Triggers

  With the area layout described in Sec. 2.2.4, it is possible to construct both a single arm and a two arm coincident trigger. The two arm trigger is used to detect the two approximately anticollinear photons emitted after the single charge exchange reaction . It incorporates both the CsI and the NaI detectors, as well as the B0B1 coincidence. The trigger thresholds on the CsI and NaI arrays are set as described in Sec. 2.2.5. The timing of the two arm trigger, shown in Fig. 2.10, is such that the CsI array starts the time to digital converter (TDC).

  
Figure 2.10: Reconstruction of the signals for the two arm trigger configuration (CsI NaI Inner (B0 B1).

The two single arm triggers are comprised of the B0B1 coincidence, and one of either the CsI or NaI detectors. In this way, it is possible to detect the photons from the single charge exchange reaction and the 129 MeV photon from the pion capture reaction . Like the two arm trigger, the thresholds for triggering the arrays are set as noted in Sec. 2.2.5. The timing of each single arm trigger is determined appropriately by the CsI and NaI arrays. The CsI single arm trigger configuration is shown in Fig. 2.11.

  
Figure 2.11: Reconstruction of the signals for the CsI one arm trigger configuration (CsI (B0 B1)).

The rates for the single arm and two arm triggers depend on that of their components. These trigger component rates for the 116 MeV/c beam runs are summarized in Table 2.3. The schematic of the electronics used in the 1997 beam time are shown in Figs. 2.12 through 2.20.

  
Table 2.3: Experimental rates for 1997 Panofsky Ratio measurement.

  
Figure 2.12: First of eight panels showing a schematic of the electronics used during the 1997 beam time. Drawing courtesy of Michael Dugger, Arizona State University.

  
Figure 2.13: Second of eight panels showing a schematic of the electronics used during the 1997 beam time. Drawing courtesy of Michael Dugger, Arizona State University.

  
Figure 2.14: Third of eight panels showing a schematic of the electronics used during the 1997 beam time. Drawing courtesy of Michael Dugger, Arizona State University.

  
Figure 2.15: Fourth of eight panels showing a schematic of the electronics used during the 1997 beam time. Drawing courtesy of Michael Dugger, Arizona State University.

  
Figure 2.16: Fifth of eight panels showing a schematic of the electronics used during the 1997 beam time. Drawing courtesy of Michael Dugger, Arizona State University.

  
Figure 2.17: Sixth of eight panels showing a schematic of the electronics used during the 1997 beam time. Drawing courtesy of Michael Dugger, Arizona State University.

  
Figure 2.18: Seventh of eight panels showing a schematic of the electronics used during the 1997 beam time. Drawing courtesy of Michael Dugger, Arizona State University.

  
Figure 2.19: Eighth of eight panels showing a schematic of the electronics used during the 1997 beam time. Drawing courtesy of Michael Dugger, Arizona State University.

  
Figure 2.20: One of eight panels showing a schematic of the electronics used during the 1997 beam time. Drawing courtesy of Michael Dugger, Arizona State University.