[Halld-cal] Installation of monitoring boards

[Elton Smith]

Dear Christine,

The forty monitoring boards arrived yesterday. After gluing two columns 
of light guides on the mini-Bcal and making all the wrappings, we went 
ahead and attached one string of LEDs to the light guides. See photos at
https://halldweb1.jlab.org/wiki/index.php/Light_Guide_Information#Installation_of_Monitoring_Boards

After some debate, but anxious to move forward with the gluing process, 
we installed the LED boards in the following way: A blob of UV-curing 
glue was placed on the PCB board behind the LED. The LED was then 
positioned on the edge of the hole away from the module. The glue was 
cured shining the light through the end of the light guide. This 
procedure should result in uniform behavior of all LEDs. The face if the 
LED should be clean. The light is directed toward the module and shines 
through the air inside the hole till it reaches the light guide. We have 
not tried this, but my guess is that we should be able to break off the 
board from the hole if we need to. Of course replacing a board with the 
light guides in place would be a challenge.

Since we did not have the controller board and you tested the LEDs 
before shipment, we went ahead and installed them with out checking them 
again. (Hope they all work).
The additional length of the cable between the LEDs seemed excessive at 
first, but we bent it around a small cylinder to avoid kinking it and 
installation went very smoothly. In fact the additional length helps 
plugging and unplugging the connectors. So the cable "pitch" and 
stiffness of the cable may be just fine.

Comments and feedback is welcome, but we plan to continue with gluing 
light guides and installation of monitoring boards tomorrow.

Cheers, Elton.

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