several promising features, one of which is its adaptation for collect- ing dry particles. The rechanical parts are entirely enclosed, It is powered by compressed gas which makes a compact source that is easily recharged and largely unaffected by atmospheric conditions. needs further engineerin, development, at future operations. 3.2.7. This device It will be field tested agein Electrostatic Precipitator This device for collecting sm#ll aerosol droplets was the mos* complicated sampling anparatus used on Project 2.5a. Its large power requirements were suplied by a notor-genersztor set. It was almost impossible to keep this equipment in operating condition, particularly after the fire caused by Shot 1 which destroyed all the spare parts for the electrostatic precipitator. Definite evaluation of the usefulness of the electrost:tic precipitator ... collecting aerosols at nuclear tests cannot be made at this time. 3.2.8 . Trigger Deviges The light trigver was a modification of the one used at IVY. On Shot 1, of 14 triggers surviving the blast effects 10 worked satisfac- torily. The fire destroyed all spare parts so the permanently dimaged triggers on the capsized rafts could not be replaced or repaired, At island stations these devices operated more satisfactorily than on refts. The electronic conditions. circuitry was improperly protected against atmospheric A simple blast trigger designed and constructed at the site opersted successfully at island and lagoon stitions for megaton weapons but was not sensitive enough for low yield weapons. Further aevelopment of this type of trigver is indicated for future field oper:tions. 3.2.9 Gamma Time-intensity Recorder This device was the seme type as those used in large numbers on the YAGts in Project 6.4. Two stations were operating before Shot-1. The one on Yoke was damaged by a water wave which occurred after that shot. The station on How operated satisfactorily throughout the operation until it was destroyed by a wave after Shot 5. It collected valuabie information concerning time and rate of arrival of fallout and its decay. The dem:zed equipment was repaired and placed on Janet in preparution for Shot Echo and later moved to Leroy. It did not record any activity after Shot 6 because no fallout arrived on thut islend. A more complete evalu- ation of,this type cf inetrumdnt will be found in the Project 6.4 final report.2</