Ocean Optics Gershun Tube - Manual

Gershun Tube
Gershun Tube 1
Gershun Tube
The Gershun Tube couples to the SMA 905 connector on a spectrometer (or to
a fiber via a splice bushing) to aperture the field of view of the spectrometer or
fiber. The Gershun Tube kit comes with user-replaceable aperture disks of 1,
3, 8, 10, and 14 degrees. It regulates field of view easily and without any
moving parts.
Without the Gershun Tube, the field of view of a standard fiber is
approximately 25 degrees. You can modify this field of view by inserting one of
the disks into the barrel of the Gershun Tube. Once installed, you secure the
disks in place with a retaining ring, which you screw into the barrel.
A ring removal tool is included with the Gershun Tube kit. Additionally, the
Gershun Tube kit includes a customized splice bushing that allows you to
connect the Gershun Tube directly to the SMA 905 termination on a fiber. The
entire Gershun Tube kit is manufactured from machined aluminum. The
interior surfaces are bead-blasted, which reduces off-axis reflections.
Additionally, the entire assembly is black anodized.
Note: With the Gershun Tube, users can achieve a 1, 2, 3, 6, 8, 10, 14, 16,
20, or 28 degree field of view. However, when using the Gershun Tube
attached directly to a fiber, the fiber limits the maximum field of view to
approximately 25 degrees. See note in Step 2 below.
Operation
Follow the steps below to install and use the Gershun Tube:
1. Thread the three components of the Gershun Tube (cone-shaped base, middle barrel, and end barrel)
together to form the Gershun Tube (if assembling tube for the first time).
2. Select the aperture disk to use with the Gershun Tube. Each aperture disk is marked with a number
indicating the field of view (in degrees) that each disk provides.
Note: Using the fully assembled Gershun Tube (all three components threaded together) and an
aperture disk will result in a field of view (in degrees) equal to the number on the aperture disk. To
achieve a field of view DOUBLE that which is printed on the disk, remove the middle component
of the Gershun Tube and assemble the tube with only the cone base and the end barrel.
With this configuration, you will achieve a field of view of 2 degrees with the 1-degree aperture
disk, a field of view of 6 degrees with the 3-degree aperture disk, etc.
3. Use the ring removal tool to remove the retaining ring from the inside of the Gershun Tube (if necessary).
Place the threaded end of the tool into the open end of the Gershun Tube and thread the removal tool
onto the ring. Remove the ring by rotating the removal tool out of the Gershun Tube.
4. Insert the aperture disk into the end of the Gershun Tube.
5. Replace the retaining ring by hand into the end of the Gershun Tube to secure the aperture disk.
6. Attach the Gershun Tube to the SMA 905 connector on the USB2000, or use the splice bushing to
connect the Gershun Tube to the SMA 905 termination of a fiber.
7. Take your measurements as you typically would.
8. Repeat Steps 2-5 to change aperture disks in the Gershun Tube.