of the thermal radiation emitted from fission and thermonuclear devices, This serie: of measurements met with a high degree of success and it now appears possible to re~ solve various disagreements in the details of thermal radiation from nuclear explo~ sions. ec. NEUTRONS Neutron spectra were obtained as a function of distance and, at a few locations, as a function of time, The results of this project were highly gratifyiny in that they filled large gaps in previously available information on bomb neutrons; only the most meager data on neutron spectra were available prior to GREENHOUSE, d. GAMMA RAYS Measurcments were made of the gamma ray apectra froma microsecond to a millisecond, and from a millisecond on, The objectives of these measurements were to determine not only the energies of the gamma rays as a function of distance, but their time dependence and distribution of the sources of this radiation as well. The se data have not yet been analyzed sufficiently to comment on the degree of success of this series of measurements. The ganma ray and neutron data have relevance to the problem of lethal range for unprotected personnel in the vicinity of a nuclear explosion and the problem of adequately shiclding against these radiations. A. REMOTE WEAPON PERFORMANGEH MEASUREMENTS a. A speciallydevised instrument, the "BHANGMETER", which measured the time from the first appearance of light to the first minimum in the light versus bene curve, was tested. This device is intended to pive a dircct reading of the bomb yicl The first model was not entircly satisfactory becnuse its response to the rather broa light minimum actually present was indefinite. Some changes were made in this model, however, which included the photographing of an oscillograph sweep, and it is believe: that a satisfactory device can be developed, A related cxpcriment of significance to military intelligence. was conducted to determine whether bomb yiclds could be determined over Long distances by analysis of light. This experiment was suggested by ex- perience on Operation RANGER whereby light from detonation was visible in LOS ANGELES At 550 miles from ENIWETOK, significant light was detected by airborne instruments from which estimates of yield could be made; however, further work is required to reSine this technique. b. A remotely recording airborne device to measure transit time was tested on the ground successfully. This device transmitted by radio a signal from the bomb to indicate the instant that the detonators were fired. first appearance of ionizing radiations, Another signal indicated the These signals were received at a remote, act.) ATOMIC ENERey AcT — 1948 BO ston