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Line 18: − The tagger microscope (TAGM) consists of six major components: upper enclosure, lower enclosure, optical fibers, electronics, shielding, and darkening shroud. As seen from the CAD image above, Figure 1, the lower enclosure houses the microscope's electronics, while the upper enclosure contains the optical fiber bundle supports (a.k.a. popsicle sticks). The bundle supports are used to align the scintillating fiber (SciFi) longitudinal axis to the incoming electron's path angle as it passes through the tagger magnet's focal plane. The designed angular tolerance, e.g. fiber to electron allowable angular error, is < 0.5<sup>o</sup>. MC simulations were performed to test the effect of various amounts of misalignment between the electron angle and the SciFi axis. Figure 4 shows a plot of one of these simulations with the solid line showing the scintillation response of the central fiber, while the dashed lines are the response for the adjacent fibers.+ − − end of the optical fibers are affixed bundle supports in the upper enclosure, and the light guide potion of the fiber extends down to the silicon photomultipliers (SiPMs) located on preamplifier boards in the lower enclosure.+ + + + + +
Moving the Tagger Microscope (view source)
Revision as of 02:13, 25 March 2021
, 02:13, 25 March 2021→Tagger Microscope
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[[Image:e-angle_fiber-amp.png|right|thumb|300px|Figure 4: Result of a MC simulation performed to predict the response of adjacent scintillating fiber columns due to fiber axis misalignment with respect to a post-bremsstrahlung electron's path. The solid line represents the response seen by the central fiber, while the dashed lines are the adjacent fibers' response.]]
[[Image:e-angle_fiber-amp.png|center|thumb|300px|Figure 4: Result of a MC simulation performed to predict the response of adjacent scintillating fiber columns due to fiber axis misalignment with respect to a post-bremsstrahlung electron's path. The solid line represents the response seen by the central fiber, while the dashed lines are the adjacent fibers' response.]]
The tagger microscope (TAGM) consists of six major components: upper enclosure, lower enclosure, optical fibers, electronics, shielding, and darkening shroud. As seen from the CAD image above, Figure 1, the lower enclosure houses the microscope's electronics, while the upper enclosure contains the optical fiber bundle supports (a.k.a. popsicle sticks). The bundle supports are used to align the scintillating fiber (SciFi) longitudinal axis to the incoming electron's path angle as it passes through the tagger magnet's focal plane. The designed angular tolerance, e.g. fiber to electron allowable angular error, is < 0.5<sup>o</sup>. MC simulations were performed to test the effect of various amounts of misalignment between the electron angle and the SciFi axis. Figure 4 shows a plot of one of these simulations with the solid line showing the scintillation response of the central fiber, while the dashed lines are the response for the adjacent fibers. A factor of three separation between adjacent signal amplitudes is achievable when alignment is < 3<sup>o</sup>. In order to achieve optimal alignment, similar to < 0.2<sup>o</sup> that was seen in bench tests, the SciFi end of the optical fibers are affixed to bundle supports (Figure 5) in the upper enclosure, with the light guide potion of the fiber extending down to silicon photomultipliers (SiPMs) located on preamplifier boards (Figure 6) in the lower enclosure.
[[Image:Mounting_Test_Popsicle_Stick.jpg|right|thumb|300px|Figure 5: Picture taken during testing phase of a bundle support with mounted fibers. Note that the bundle support does not have its mounting rods installed. These rods are used to secure the bundle support to the parallel railing system located in the upper enclosure.]]
[[Image:SiPM_alignment.png|right|thumb|300px|Figure 6: Image of the preamplifier board and open chimney (light guide holder) before fiber installation. The chimney aligns the 2mm<sup>2</sup> lightguide end to the center of the 3mm<sup>2</sup> active area of the SiPM with only a 0.5mm air gap between the two.]]
==Coordinate System==
==Coordinate System==