In
each of the six sectors of CLAS12, the FTOF system is comprised of three arrays of counters,
referred to as panels, named panel-1a, panel-1b, and panel-2. Each panel consists of a set
of rectangular scintillators with a PMT on each end. Panel-1 includes the sets of counters
located at forward angles (roughly 5◦
to 35◦
) (where two panels are necessary to meet the
80 ps average time resolution requirement) and panel-2 includes the sets of counters at larger
angles (roughly 35◦
to 45◦
). The positioning and attachment of the FTOF detector arrays
to the Forward Carriage of CLAS12 are shown in Fig. 1. Each of the six panel-1a arrays
contains 23 counters, each of the new highly segmented panel-1b arrays contains 62 counters.
and each of the panel-2 arrays contains 5 counters.
Figure 1: View of the FTOF counters for CLAS12 highlighting the location of the panel-1 and panel-2 counters. The panel-1b counter arrays are shown in orange and the panel-2 counter arrays, mounted around the perimeter of the Forward Carriage, are shown in red. The panel-1a counter arrays mounted just downstream of the panel-1b arrays are not visible in this picture. The Forward Carriage is roughly 10 m in diameter.
Figure 2: View of the FTOF scintillators for panel-1a, panel-1b, and panel-2 in the sector mid-plane with the key parameters indicated.
Sectors
Figure 3: View of the upstream face of the Forward Carriage in Hall B showing the CLAS12 sector naming conversion for Sector 1 (S1) through Sector 6 (S6). The dashed lines denote the mid-planes for each sector.
Panel 1A
Figure 4: View of the face of a generic FTOF panel-1a array showing the numbering scheme for the 23 scintillators that make up the counters in each of the six sectors of CLAS12.
Panel 1B
Figure 5: View of the face of a generic FTOF panel-1b array showing the numbering scheme for the 62 scintillators that make up the counters in each of the six sectors of CLAS12.
