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This Defense Intelligence Reference Document was prepared by the Defense Intelligence Agency under its Advanced Aerospace Weapon System Applications (AAWSA) program, is dated 6 April 2010 and is part of a series of advanced technology reports produced in FY 2009. It reviews proposed laboratory generators and detectors of high-frequency gravitational waves for communications. It favors an infrared-excited molecules transmitter and the Li-Baker detector, estimating about 1.9 million bits per second over 7,000 km through the Earth. It also discusses timing standards and interplanetary navigation uses.
“Cooper”1 page
UNCLASSIFIED/ /F81il 8FFHil.tzk Wili 8HkY disadvantage that this device is of a unique design that is currently available only from Yale University, and is likely not to be exportable. This task will include developing a conceptual design using this alternative type of receiver for the PPF arising from HFRGW. DD1.6 Cryogenic System Specification and design of the cryogenic system refrigeration unit, required for low- temperature operation to obtain the best possible reduction in intrinsic thermal noise: Dr. R.C. Woods (LSU) + graduate student, Dr. R. M L Baker (TSC), G.V. Stephenson (TSC). The required criterion is that the temperature T satisfies kBT << hw (where kB is Boltzmann's constant); that is, T << hw/kB ~ 480mK for detection at 10GHz. This condition is satisfied by the target temperature for the interaction volume T < 48mK, which can be obtained using a common helium-dilution refrigerator. Then, the signal PPF will be significantly greater than the thermal photon flux. Cost/performance tradeoffs may also be important in this design, so that other possible economic solutions to receiver cooling will also be considered before finalizing the design. DDl.6.1 Off-the-shelf cryogenic systems: a number of companies have developed ultra-low temperature systems (mK range) for a variety of applications. A common application is refrigeration of receivers as needed in the Li-Baker HFRGW detector. One possibility is the Oxford Instruments' KelvinoxMX range (see summary data attached) that appears to suit the present requirements subject to further evaluation of each model in the range. Other manufacturers to be investigated include Scientific Magnetics (UK), and Cryofab Inc. (Kenilworth, New Jersey). DDl.6.2 Specifications for system best suited to the detector: specifications will be established for the selected cryogenic system. This will include cryogen level monitoring devices (for example, Oxford Instruments Intelligent Level Meter ILM200) for warning if the cooling fails. DD1.7 Electromagnet Development of the electromagnet specification needed to produce the required static magnetic field (up to 35T, ~3T nominal): Dr. R.C. Woods (LSU) + graduate student, Dr. R. ML Baker (TSC), G.V. Stephenson (TSC). It is expected that a commercial design can be identified for this task. The chosen design will be capable of providing the requisite magnetic field at least over the interaction cavity volume in the containment vessel. Exceptional field-uniformity is not a particularly important issue in this application, though the GW interaction volume or cavity (roughly cylindrical, 6cm diameter and 30cm long) plus extra volume for the surrounding apparatus is somewhat larger than many other experimental applications require, and the required field is perpendicular to the cylindrical axis. Hence, one solution is that the final solenoid design must completely surround the cylindrical axis of the interaction volume perpendicular to the applied field. An alternative approach is to use two solenoids, one each side of the interaction volume, similar to the popular Helmholtz coil configuration. In a development of this, a number of small ( ~6cm diameter) solenoids could be stacked along the length of the interaction volume, with their Helmholtz-like opposite paired solenoids the other side of the interaction volume. In the latter cases, since the paired solenoids are not perfect ring coils, the resultant field would be non-uniform. A 49 UNCLASSIFIED/ ,'1"91t 91"1"1@1it.l! l!l!il! 8111!¥
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Report, from the dia collection. The PDF is mirrored here; the original link is above. 57 pages are in the text index: search them above, or from the library's search.