Difference between revisions of "Collimation System"
Line 12: | Line 12: | ||
− | [[image:acol_open_4.jpg|300px]] | + | <table width="90%"><tr> |
− | [[image:acol_open_5.jpg| | + | <td width="50%" align="center">[[image:acol_open_4.jpg|300px]]</td> |
+ | <td width="50%" align="center">[[image:acol_open_5.jpg|280px]]</td> | ||
+ | </tr></table> | ||
Figure 2. Images of the GlueX active collimator during assembly. The aluminum frame fits down over the tungsten wedge assembly and provides electrostatic shielding and isolation for them. | Figure 2. Images of the GlueX active collimator during assembly. The aluminum frame fits down over the tungsten wedge assembly and provides electrostatic shielding and isolation for them. |
Revision as of 14:16, 27 October 2014
The GlueX active collimator consists of 8 separate tungsten wedges placed symmetrically in two concentric rings around a 5-mm diameter clearance hole. It can be placed over any primary collimator aperture that is 5mm in diameter or smaller, and provide 8 independent signals which come into balance when the photon beam spot is properly centered on the collimator aperture. The wedges are mounted as shown inside a cylinder made of boron nitride, a white soft ceramic material that is an excellent insulator as well as being machinable and mechanically robust. The placement of the wedges on the boron nitride substrate are shown below.
![]() |
![]() |
Figure 1. Images of the GlueX active collimator during assembly. There are 4 identical inner wedges and another set of 4 identical outer ones. The rows of pins on the inner radius of each wedge are critical to their performance as a local photon flux monitor.
After the wedges are installed, a mating aluminum frame is lowered into the cylinder. It is designed with separate compartments for each wedge, and serves as an electrostatic shield and isolates the return currents. Fig. 2 shows this frame before and after installation in the boron nitride housing.
![]() |
![]() |
Figure 2. Images of the GlueX active collimator during assembly. The aluminum frame fits down over the tungsten wedge assembly and provides electrostatic shielding and isolation for them.