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Neutron detection and multiplicity counting has been investigated using a boron-loaded plastic scintillator (BC454)/bismuth germanate (BGO) phoswich detector array. Boron-loaded plastic combines neutron moderation (H) and detection ({sup 10}B) at the molecular level, thereby physically coupling increasing detection efficiency and decreasing die-away time with detector volume. Separation of the phoswich response into its plastic scintillator and bismuth germanate components was accomplished on an event-by-event basis using custom integrator and timing circuits, enabling a prompt coincidence requirement between the BC454 and BGO to be used to identify neutron captures. In addition, a custom time-tag module was used to provide a time for each detector event. Time-correlation analysis was subsequently performed on the filtered event stream to obtain shift-register-type singles and doubles count rates.

The complete microcomputer controlled system consists of two interrelated subsystems. The first is the fast rabbit system for moving the sample in and out of the reactor at specified times and the second is the receiving station for the rapid automated chemical program for the irradiated sample and its disposal. The system allows operator interaction. (JSR)

A remote-local controlled 4K channel, 32 bits per channel pulse height analyzer (PHA) built around a Fortran programmed LSI-11 is described. The PHA is made up of an LSI-11 microcomputer with 20K of memory, an interface to a Northern Scientific ADC, an 8 bit parallel link to a master LSI-11 computer, and a serial 9600 baud link to a shared DEC VT55 graphics terminal. There are 4 PHAs all networked to a remote master computer that make up the total PHA system. This PHA system will gather X-ray and ..gamma..-ray spectra data from neutron activated rabbit samples for the Lawrence Livermore Laboratory NURE project. NURE is an acronym standing for the National Uranium Resource Evaluation. The goal of NURE is to conduct a multidisciplinary survey of the uranium mineral resources in the United States and publish an assessment of the national uranium reserves by mid-1981. The purpose of LLL's part is to process the samples taken from the western 1/4 of the U.S. and publish the results. A secondary purpose of the analysis is to identify any other elements in the sample for future reference.