The requirements for multiple-coincidence counting systems with 10{sup -8}- to 10{sup -9}-sec time resolution can be met economically with presently available high-frequency transistors. The design of solid-state coincidence circuits, amplitude discriminators, and decade scalers is considered and their operation discussed. Several systems have been designed utilizing up to 180 channels from scintillation detectors.

A new rear nozzle has been developed by Mechanical Development (A), IPD to alleviate the stuck gun barrel problem on the process tubes at F reactor. This nozzle is called the 105-F rear face floating nozzle (RFFN) and is shown in Figure 4. The purpose of this study was to determine the hydraulic operating characteristics of this nozzle and to compare these characteristics with those of the standard nozzle assemblies. This report is essentially an addendum to EW-63756 1 which presented energy loss data for various outlet fitting assemblies for possible use on the BDF type reactors The experimental data for this study were obtained with the use of the hydraulics mockup in the 189-D Thermal Hydraulics Laboratory.