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Show I SECTION 2. 0 INSTRUMENTATION, OPERATIONS, AND DATA COLLECTION 2. 1 Nuclei Generation Near th e end of the first data collection season, several generator types were constructed, or procured, and tested on Emerald Mountain. Two of these were needle types (Colorado State University (CSU) modified Skyfire and Bollay modified Skyfire) and one a pressure nozzle type generator (th e Bollay modified Skyfire Hi Output Type). The latter proved to be th e most reliable and easiest to keep clean. This typ e of generator (shown in Figure 2) was chosen for Park Range nucleation operations and performed flawlessly for four winter seasons of intensive operation. Shortly after operations were started, a flow metering system was added to the generator system. With the flow metering system, these generators make an extremely reliable and effective generating system. The generators were operated using a 4% solution of Agl in acetone complexed with sodium iodide. The burn rate of Ag I was just over 2 gm min -1. The units were calibrated extensively at Colorado State University's facility at Fort Collins and gave a consistent calibration curve. The output of the modified Skyfire high output generator is conservatively 3 x 10 1 4 nuclei gram- 1 at -20°C . (Calibration curves for several generators are presented in Figure 3. ) The burn rate used was 0. 035 gm sec-1, so that the output per generator was approximately 1 x 1013 nuclei sec- 1 . The assumptions under which the experimental plan was devised were: it was desired to fill a target volume 20, 000 m long by 3000 m high with a nuclei concentration of 10-4 m-3 effective at -20°C, with a flow through the volume of 15m sec- 1 . The required generator output is therefore 2. 0 X 10 4 X 3. 0 X 10 3 or ,.__, 10 X 13 15. 0 X 10 4 nuclei sec = 9. 0 X 10 12 -1 14 If we conservatively assume the nuclei output to be 10 nuclei gm -l, then about 0. 10 gm sec -1 would have to be burned to produce this output. The two generators that were used routinely burned a total slightly less than this amount. An AgI - isopropylamine generator was also tested. Based on an aircraft tracking diffusion test, it was determined to have an output at least as great as the two Skyfire high output generators. Calibration tests at CSU showed a higher output. Due to the toxic and corrosive nature of the solvent, this generator was not used for routine operations. 7 |
