Nikita Bernier wrote: |
Monday, March 19, 2012, 17:04
Target boat contains 4 BeO pellets with 30% PVB:
Sample, Thickness (mm), Mass (g), Density (g/cm3)
1 4.943, 0.9628, 1.265
2 4.930, 0.9685, 1.276
3 4.758, 0.9607, 1.312
4 4.979, 0.9872, 1.288
Target chamber is currently being pumped down. Leak check will be done tomorrow by turning on the cooling water for the heat shield.
Wednesday, March 21, 2012, 18:30
The Evaporator #2 backing pump (IEVAP2BP1) muffler has been connected to the exhaust system.
The auto-ramp program has been tested today and works well.
Evaporator #2 is now auto-ramping overnight at 1 A/min, up to 500 A, between 5.00e-05 and 6.00e-05 Torr.
ISAC ops have been informed of the process and they will include it in their walkaround.
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After sintering at up to 500 A (~1000°C), the 4 BeO pellets have shrunk and feel robust. We can manipulate them with tweesers or hands. Also we can drop them from a couple of inches high and they don't break.
One of the pellets rolled to the extremity of the target boat tube and still has black traces from bad sintering on one side.
Sample, Thickness (mm), Mass (g), Diameter (mm), Density (g/cm3)
1 3.688, 0.7118, 11.231, 1.948
2 3.822, 0.7196, 11.241, 1.897
3 3.810, 0.7037, 11.188, 1.879
4 3.803, 0.7077, 11.269, 1.866
The average thickness before sintering was 4.90 mm. After sintering, 3.78 mm. Thus the average thickness loss is 1.12 mm (22.9%)
The average mass before sintering was 0.9698 g. After sintering, 0.7107 g. Thus the average mass loss is 0.2591 g (26.7%)
The average diameter before sintering was 14.35 mm. After sintering, 11.23 mm. Thus the average diameter loss is 3.12 mm (21.7%)
The average density after sintering is 1.897 g/cm3, compared to the density of BeO (3.01 g/cm3). Thus the pellets have a BeO density of 63.0%.
Evaporator #2 is now off. |