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Moving the Tagger Microscope (view source)
Revision as of 21:35, 24 March 2021
, 21:35, 24 March 2021→Moving the Tagger Microscope along the Focal Plane
=Moving the Tagger Microscope along the Focal Plane=
=Moving the Tagger Microscope Along the Focal Plane=
==Tagger Microscope==
The tagger microscope (TAGM) consists of six major components: upper enclosure, lower enclosure, optical fibers, electronics, shielding, and darkening shroud. 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) long axis to incoming electron's path angle (at the tagger magnet's focal plane. 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.
==Coordinate System==
==Coordinate System==
There are three coordinate systems often referred to inside the GlueX Tagger Hall. These coordinate systems have origins associated with the Goniometer center (room coordinates), Tagger Magnet center (map coordinates), and the focal plane (FP coordinates). The room coordinate system has the positive z-coordinate along the beam axis with the positive y direction pointing to the ceiling of the tagger hall from the coordinates origin placed at the Goniometer's center, where the beamline radiator is located. Figure 1 shown below, taken from a presentation by Dan Sober, shows the three coordinate systems relative to one another. The map coordinate system (magnetic mapping) places the y-coordinate along the long axis of the magnet with the positive x-axis parallel to the tagger hall floor in the direction of the focal plane. the positive z-axis of the map coordinate system points toward the tagger hall ceiling. When viewed from above the map y-coordinate is offset from the room coordinate z-axis by 6.5 degrees towards the focal plane (clockwise). The focal plane coordinate system places its x-axis along the electron focal plane with zero being at an electron energy equivalent to a photon energy around 11.7 GeV. The positive x-axis points toward increasing electron energy (decreasing photon energy). The positive y-axis of the focal plane coordinate system points towards the tagger magnet and is parallel to the tagger hall floor. This leaves the focal plane positive z-axis pointing towards the tagger hall ceiling.
There are three coordinate systems often referred to inside the GlueX Tagger Hall. These coordinate systems have origins associated with the Goniometer center (room coordinates), Tagger Magnet center (map coordinates), and the focal plane (FP coordinates). The room coordinate system has the positive z-coordinate along the beam axis with the positive y direction pointing to the ceiling of the tagger hall from the coordinates origin placed at the Goniometer's center, where the beamline radiator is located. Figure 1 shown below, taken from a presentation by Dan Sober, shows the three coordinate systems relative to one another. The map coordinate system (magnetic mapping) places the y-coordinate along the long axis of the magnet with the positive x-axis parallel to the tagger hall floor in the direction of the focal plane. the positive z-axis of the map coordinate system points toward the tagger hall ceiling. When viewed from above the map y-coordinate is offset from the room coordinate z-axis by 6.5 degrees towards the focal plane (clockwise). The focal plane coordinate system places its x-axis along the electron focal plane with zero being at an electron energy equivalent to a photon energy around 11.7 GeV. The positive x-axis points toward increasing electron energy (decreasing photon energy). The positive y-axis of the focal plane coordinate system points towards the tagger magnet and is parallel to the tagger hall floor. This leaves the focal plane positive z-axis pointing towards the tagger hall ceiling.