[Halld-cal] First two production light guide sets pass dimensional checks

[Elton Smith]

Dear collaborators,

I checked the light guides from the first two production sets against 
the go-nogo jig and measured the length using a caliper. There were two 
findings worth mentioning.

All guides passed the go-nogo gauge except for guide F-15, where the 
base check failed. However, measurements of the dimensions with the 
caliper found the guide was in accordance with the drawing. I will have 
to re-check the guide and the jig. Nevertheless, when guide F15 was 
placed in the jig slot with 9 other guides (all chosen from the top left 
pocket in the  box), the set fit nicely. Therefore, even if the guide is 
imperfect, it can be used as part of a set.

The lengths of the light guides are systematically longer than the 
nominal value of 80.00 mm, as recorded in detail by USM before shipping. 
We allowed exceptions to the tolerances for those sets, with the maximum 
outlier being guide A-18 with a measured length of 80.204 mm. Our 
measurements also picked out the outlier, with a caliper measurement of 
80.23 mm. We note that the caliper measurements may be systematically 
high for the length with only hand alignment.

We conclude that the first two production light guide sets meet our 
dimensional checks.

Cheers, Elton.

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