Changes

The ideal configuration of the each fiber column would allow the center of the front face of the fibers to sit on the focal plane, as shown in Figure 2. Unfortunately, this configuration does not permit sufficient space to provide a method for holding the fibers in place other than gluing. During the prototyping phase testing showed that gluing the fibers to the bundle support was not a viable option due to unacceptable light loss, not to mention the difficult that would arise when trying to replace fibers. A 5x5 fiber configuration per bundle was used for the prototype, which was optically linked to a single preamplifier board. Unfortunately, having 25 silicon photomultipliers (SiPM) per preamplifier board led to too much electronic cross-talk and the likelihood of optical cross-talk between channels due to limited spacing between SiPM. Bundle supports with smaller fiber array configurations have too narrow of a base and could lead to improper alignment of the fibers due to the instability of the bundle support on the mounting rails. While using a bundle support with 6 or more columns side-by-side, as in Figure 3, extends the fibers too far past the focal plane in the y-direction.  A compromise was reached by designing a bundle support with 30 fibers (5x6 array), which was split into two 5x3 fiber arrays (forward and rear bundle halves) offset to one another. This configuration shown in Figure 4 limits the fibers' intrusion past the focal plane (± Y_FP) and reduces the number of SiPM to 15 per preamplifier board by using one board per bundle half. The offset of the bundle halves is such that when placed at a β = 12^o the focal plane will pass through the center face of the center fiber in each bundle half.  

The ideal configuration of the each fiber column would allow the center of the front face of the fibers to sit on the focal plane, as shown in Figure 2. Unfortunately, this configuration does not permit sufficient space to provide a method for holding the fibers in place other than gluing. During the prototyping phase testing showed that gluing the fibers to the bundle support was not a viable option due to unacceptable light loss, not to mention the difficult that would arise when trying to replace fibers. A 5x5 fiber configuration per bundle was used for the prototype, which was optically linked to a single preamplifier board. Unfortunately, having 25 silicon photomultipliers (SiPM) per preamplifier board led to too much electronic cross-talk and the likelihood of optical cross-talk between channels due to limited spacing between SiPM. Bundle supports with smaller fiber array configurations have too narrow of a base and could lead to improper alignment of the fibers due to the instability of the bundle support on the mounting rails. While using a bundle support with 6 or more columns side-by-side, as in Figure 3, extends the fibers too far past the focal plane in the y-direction.  A compromise was reached by designing a bundle support with 30 fibers (5x6 array), which was split into two 5x3 fiber arrays (forward and rear bundle halves) offset to one another. This configuration shown in Figure 4 limits the fibers' intrusion past the focal plane (± Y_FP) and reduces the number of SiPM to 15 per preamplifier board by using one board per bundle half. The offset of the bundle halves is such that when placed at a β = 12^o the focal plane will pass through the center face of the center fiber in each bundle half.  

<gallery caption="Fiber Array Size" widths="300px" heights="300px" class="center">

<gallery caption="Fiber Array Size" widths="300px" heights="300px" class="center">

</gallery>

</gallery>

[[Image:Single_column_configuration.png|center|thumb|700px|Figure 2: CAD image showing each fiber column with the center of its front face on the focal plane. The fibers are at &beta; = 20^o.]]

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===<u>A summary of the spreadsheet calculations is a follows:</u>===

===<u>A summary of the spreadsheet calculations is a follows:</u>===