1 Some Water Extreme Calculations TK Hemmick for the Tent Crew

2 Overview: HBD is now out of Glove Box. Small Shot of air seems to have gotten in. Leak check revealed leaks that were the sealed effectively. Starting point (after 1-2 hours of flow) –Oxygen 230 ppm. –Water 65 ppm. Present levels (2.75 l/min flow): –Oxygen – 2 ppm. –Water – ppm (depending upon temp?) Consequences: –No danger to cathode QE. –Transparency loss significant.

3 Water Removal Rate Treat the water as an ideal gas whose volume is 30/1,000,000 of the HBD Volume (i.e. 30 ppm water by volume). –V tot = 300 liters = 0.3 m 3 –V water = 0.3 m 3 * = m 3 PV=nRT; n=PV/RT –n=100000* /(8.315*300) = 3.6 x –m = 3.6 x moles * 18 g/mole = 6.5 mg Presently we’re flowing ~3 liters/min which is ~1.5 hours/turn = ~16 turns/day 6.5 mg * 16 ~ 100 milligram/day.

4 Water Limits Assume that the total amount of water was equal to the HBD volume filled with 50% humidity air. Assume air was right amount to put 500 ppm * Oxygen into vessel. –Normal air O 2 =0.21 –Fraction = The second of these should be realistic. * 230 ppm of oxygen was measured after ~1 turn of gas.

5 Water Removal Rate For Glove Box (for extreme conditions) Volume of the glove box is 3.4 m 3 US%3Aofficial&q=%28%28102+cm+*+83+cm%29+%2B+%28+2+*+%2883+cm+*+9+cm+%2F2+%29%29%29+*+370+cm+in+meters+%5E+3&btnG=Searchhttp:// US%3Aofficial&q=%28%28102+cm+*+83+cm%29+%2B+%28+2+*+%2883+cm+*+9+cm+%2F2+%29%29%29+*+370+cm+in+meters+%5E+3&btnG=Search - V water = 3.4 m 3 * =.0068 L PV=nRT ; n=PV/RT - n=100000*0.0068/(8.315*300) = 2.7 x moles - m = 2.7 x * 18 g/mole = 4.9 mg US%3Aofficial&q= Pa+*+3.4+m%5E3+*+2+%2F %2F+% Joules+%2F+%28mole+Kelvin%29%29+%2F+300+Kelvin&btnG=Searchhttp:// US%3Aofficial&q= Pa+*+3.4+m%5E3+*+2+%2F %2F+% Joules+%2F+%28mole+Kelvin%29%29+%2F+300+Kelvin&btnG=Search The box flows 50 cfm or 600 turns/day 4.9 mg * 600 ~ 3.0 grams/day Another way: –If 3 grams per day makes 2 ppm. –Then 0.1 grams per day makes 0.06 ppm.

6 Conclusions: The present out-gassing rate of the HBD would have produced a negligible change in the glove box readings (maybe all along?) The 9 mg of contamination is likely MUCH closer to the truth and would have been removed in 0.1 days. (NOT the trouble!!) It is likely that this out-gassing rate of the HBD is not due to the air leak. (O 2 low) It is unknown how much time is required to reduce the water enough for operation.

7 Possible Actions Pump the HBD? –Could be possible. –WOULD be stupid. Warm the HBD? –Turn on all Electronics Cards Warms the detector to realistic running conditions. Allows double-check of noise levels. –Warm the gas Stainless piping cannot be used to warm the gas. Need to add 50’ Cu tubing to supply side. Use temperature controller to warm pipe. –Flow through bypass until pipe clean –Flow through detector to accelerate water removal. Other Ideas?