Mirror prototype test plan
Contents
Testing of existing mirror box
After the mirror box removal, the following tests should be performed to study the damage to the mirrors
- Water/food dye leak check
- Initial spot check with dye for clear leak sources
- Submerge full mirror piece in water tank with dyed water to identify possible leak sources
- Relative reflectivity mirror measurement
- Compare reflectivity of know sample mirror and those from mirror box similar to [1]
- Further studies could be done in detector group's Big Blue Box, etc.
Proposed prototypes
Small samples ~(2x2 in) should be made for testing under water and reflectivity measurements. Below are the suggested fabrication steps to produce test pieces. For reproducibility we could make 3 of each sample. All these should be tested with standard glass pieces prior to using borosilicate and UVE mirror.
Supplies needed:
- Clear DP270 and applicators (stock room items?)
- Epotek301-2 and 301-2FL epoxy (ordered by Mark)
- Spray on screen protector (Tim provides information to Mark?)
- Glass/mirror pieces (cut by Keith or Danny's glass?)
- ~20 pieces of 2x2 in standard glass samples for testing epoxy application processes
- ~20 pieces of 2x2 in borosilicate glass for prototypes
- ~23 pieces of 2x2 in UVE mirrors for prototypes
- Bell jar from detector group (Tim request from Brian Cross?)
- "Bag" for pumping on glass/mirror sandwich (Keith re-assemble in Hall)
Wider epoxy seal
Follow similar procedure as existing mirror box, but use wider strip to provide better water seal
- Borosilicate + UVE mirror with DP270 2 cm wide strip around edge
Notes:
- Some mirrors were successfully sealed in existing mirror box, what is unique about them?
- Concern about how we get such a thick ring of epoxy around the edge with the previous "wicking" approach of putting a bead on the outside and let it seep between the two layers. Could bevel the edge of the protective glass to provide larger sealing surface to apply epoxy.
Full epoxy
Setup small "bag" with blue film to sandwich protective glass against mirror surface using pump. Keith previously setup something like this in the Hall last year
- Borosilicate + UVE mirror sandwich with DP270 entirely between surfaces
- Borosilicate + UVE mirror with Epotek301-2 entirely between surfaces
Epoxy layer
Use bell jar from detector group to pump
- UVE mirror with Epotek301-2 poured on and cured over ~days under bell jar to investigate procedure
- UVE mirror with Epotek301-2FL poured on and cured over ~days under bell jar to investigate procedure
Notes:
- This requires level surface for even curing of "flat" coating of Epotek
- Consider solutions for "dam" around mirror to keep fixed thickness of epoxy
Screen protector
Stephanie suggested an off the shelf wipe-on screen protector. Tim found a spray on version as well that may be easier to apply
- UVE mirror with screen protector applied
Rear surface mirror
Would need to find a vendor for high reflectivity rear-surface mirror of large size
- Seal rear surface of mirror with 3M strips and silicone against aluminum(?) piece
Test plan
After prototypes are produced (by early December), make the following tests:
- measure reflectivity relative to control UVE mirror
- for one control sample of each prototype, measure the wavelength dependence in the Big Blue Box
- use laser to evaluate impact of any non-uniformity of epoxy layers (speckling)
- place one sample in water bath and one sample under UV lamp to test stability
- each week, take samples out of water/lamp setups and measure relative reflectivity
Goal: decide on full scale prototypes to produce by the end of 2020 for testing in December/January