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This report discusses national urban growth policy and provides summaries of eight Congressional seminars on the topic.

In 1968, Luis Alvarez suggested that a high-resolution multiwire particle detector could be developed using a thin layer of liquified noble gas as the detection medium. After key problems in chamber construction, purification, and readout had been solved, a spatial resolution of 15 {micro} rms was demonstrated. Work is in progress to build high-resolution chambers and measure their properties for particle physics experiments at high-energy accelerators. The liquid xenon multiwire chamber also has potential in nuclear medicine for imaging isotope distributions with an unprecedented combination of gamma-ray detection efficiency and spatial resolution. A preliminary 24-wire chamber has been constructed; this chamber detects 280-keV gamma rays with 65% efficiency and 4-mm FWHM spatial resolution. Initial images of point and distributed sources are very promising, and the liquid purity can be maintained for periods exceeding several days.

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Blowdown/reflood testing of two heater rods containing laser welded thermocouple attachments is described. Two series of tests were conducted, one of three and another of nine blowdowns. Test parameters were controlled such that the blowdown/reflood cycles duplicated those predicted for the LOFT reactor. Thermocouple performance throughout the test series was very good in that the only failures observed were caused by bowing of the heater rod. Data from all tests are included as are photographs of laser welds taken at various times during the test series. Although heater rod bowing did cause failure of some of the welds, actual fuel pins are restrained and thus not expected to bow to this extent. When weld failure does occur it appears in the form of a separation at the bond between the Titanium fillet and Zircaloy. This does not impair either the performance or the integrity of the fuel cladding in any way.

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This report is an outline of the Older Americans Comprehensive Services Amendments of 1973.

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A new method is described for treating fluorescence, which replaces the original subroutine of the Monte Carlo photon code (MCP), and eliminates its most undesirable features. The major changes include (a) elimination of the very inaccurats 1/E/sup 3/ law for photoelectric cross section, b) updating of relative intensities of K-fluorescence lines, (c) elimination of fluorescence from shells other than K and L, and (d) provision for secondary L-fluorescence. Except for the latter, the previous code is unchanged, as well as the storage format. However, the change in method is reflected in the new constants, which have been completely revised, and are included here in tabulated form. (auth)

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A separate abstract was prepared for each section of the report. (DHM)

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