15. One cause of lumen degradation of metal halide arc lamps is contamination inside of the arc chamber and lamp jacket. A brainstorming session to address excessive lumen degradation identified four variables that might affect contamination. To test for variable effects a 24 full factorial experiment design with two replicates in blocks was built using the following variables matrix: Variable A: HF acid wash B: Cadmium concentration + Units No Yes 2 4 % C: Vacuum exhaust time 30 60 seconds D: Jacket getter 8 16 mm The experimental run matrix is shown below. The lumen maintenance response, LM, is the ratio of 1000 hour lumens to 100 hour lumens. 1 23 4 567890122156762222222222223333 AUUSLB527 B D E F C H SO RO PtType Blocks HF Cd ExTime Getter LM 10 16 123 1 1 1 2 30 16 0.948 1 1 1 4 60 16 0.955 1 1 1 -1 2 30 8 0.839 13 4 1 1 -1 2 60 16 0.855 5 1 1 -1 2 60 8 0.855 11 6 1 1 -1 4 30 16 0.901 7 1 1 -1 4 60 8 0.885 12 8 1 1 1 4 30 16 0.973 14 9 1 1 1 2 60 16 0.941 8 10 1 1 1 4 60 00 8 0.950 2 11 1 1 1 2 30 8 0.928 14 24 423622222222222222222 15 23 12 1 1 1 4 30 8 0.973 13 1 1 -1 4 60 16 0.905 14 1 1 -1 4 30 8 0.937 15 16 27 17 18 569% 1 1 1 2 60 8 0.955 1 1 -1 2 30 16 0.833 1 2 -1 4 30 16 0.935 1 2 1 2 30 16 1.008 31 19 1 2 -1 4 60 16 0.908 29 20 1 2 -1 2 60 16 0.865 21 21 1 2 -1 2 60 8 0.853 22 1 2 1 2 60 8 0.940 17 23 1 2 -1 2 30 8 0.885 20 24 1 2 1 4 30 8 0.982 19 25 1 2 -1 4 30 8 0.893 28 26 1 2 1 4 30 16 0.970 27 1 2 -1 4 60 8 0.890 30 28 1 2 1 2 60 16 29 1 2 1 4 60 8 600 0.949 0.967 18 30 1 31 1 25 32 1 222 2 117 1 24 30 8 0.957 60 16 0.944 -1 2 30 16 0.865 34