[Halld-cal] Light guides have been glued onto mini-Bcal

[Elton Smith]

Dear collaborators,

We completed gluing all light guides onto the mini-Bcal on Friday. Some 
photos are available at
https://halldweb1.jlab.org/wiki/index.php/BCAL_Beam_Tests_2012#Photos_and_Plots

By-in-large the process was a success. All guides fit together very well 
and the monitoring boards arrived from Athens just in time to attach 
them to the center two columns on both sides. The gluing procedure 
proceeded one guide at a time, where we hope to develop a production 
scheme that allows us to glue one column at a time. We are improving the 
tooling to accomplish this goal.

In the process of mounting the Bcal monitoring boards one LED broke off, 
so we have one missing board on the K guide next to the missing guide 
where we still have access. Christina has sent us some spare LEDs to 
repair the broken board. As far as we could tell we did not bump or 
mistreat that LED board, so we are not sure why the LED broke off.

One concern is the width of the light guides relative to the mini-Bcal. 
We started gluing the left-most column and, by design, its edge is 
starts 0.5 mm inside the module. This ensures that the placement of an 
adjacent module (in the full experiment) is not impacted. However, the 
edge of the right-most column extends beyond the right side of the 
module by about a 0.5 mm. This is not a problem for the present ectype, 
but we need to understand why the complement of light guides are not 
undersized. We took measurements of each light guide and the mini-Bcal 
and will check where the dimensions are slightly off. The design left 
some slight gaps for the glue and we do not think these have been exceeded.

More discussion on this later.

Cheers, Elton.


-- 
Elton Smith
Jefferson Lab MS 12H5
12000 Jefferson Ave
Suite #16
Newport News, VA 23606
(757) 269-7625
(757) 269-6331 fax