NSA is a comprehensive collection of international nuclear science and technology literature for the period 1948 through 1976, pre-dating the prestigious INIS database, which began in 1970. NSA existed as a printed product (Volumes 1-33) initially, created by DOE's predecessor, the U.S. Atomic Energy Commission (AEC). NSA includes citations to scientific and technical reports from the AEC, the U.S. Energy Research and Development Administration and its contractors, plus other agencies and international organizations, universities, and industrial and research organizations. References to books, conference proceedings, papers, patents, dissertations, engineering drawings, and journal articles from worldwide sources are also included. Abstracts and full text are provided if available.

Radioactive (a, n) neutron sources include Ra-Be, PuF4, and four PuBe13 sources. Comparative neutron emission rates were determined by two separate methods: (1) the manganese sulfate bath with appropriate corrections made for fast neutron escape or capture and for thermal neutron capture by the source; and (2) long counter measurements corrected for energy response and so rce anisotropy. Agreement to within 1 percent was obtained by the two independent methods. A Ra-Be source calibrated against the NBS neutron standard was used as a primary reference Spectral measurements of PuBe13 and PuF4 neutron sources were made with nuclear emulsions. By the use of cylindrical plastic and lead absorbers, an effort was made to moderate the PuBe13 spectrum and thereby obtain additional calibration points for instrument response studies. Spectral changes were initially studied with the doublemoderator technique, followed by later measurements with nuclear emulsions. From flux and spectral measurements of the primary and moderated radioactive sources, the first collision tissue dose was calculated and, in turn, compared to experimental measurements of absorbed dose with proportional counters designed according to the Bragg-Gray principle. (Author).