Speaker
Dr
Alex Smith
(University of Minnesota)
Description
NOvA is a long-baseline neutrino oscillation experiment that will use the Fermilab NuMI beam and new near and far detectors located at Fermilab and Ash River, Minnesota.
The 15 kiloton far detector consists of 12,028 16m x 1m x 7cm liquid scintillator-filled modules, laminated into 16 m x 16 m blocks. These modules are constructed from PVC plastic extrusions to produce a structure of 32 tubular cells which are outfitted with wavelength shifting fibers. Plastic parts are glued to these extrusions in order to route the sixty-four fiber ends to an optical connector and also to create a liquid-tight seal for the liquid scintillator. Assembly of these modules involves many delicate assembly tasks and custom test equipment. There are stringent leak, light output, and dimensional tolerances on the completed modules. During peak production, the assembly labor force will consist of a crew of approximately 200 part-time student employees, working an average of about twelve hours per week, managed by five full-time employees and two managers.
A comprehensive system has been developed to ensure the quality of the NOvA modules and to make possible the challenging task of managing a large part-time work force with a small management team. Each assembly step is monitored and directed using screen prompts and audio feedback in order to prevent mistakes. Should any problems arise, the data collected will allow us to quickly identify and correct them. Input is provided using wireless bar code scanners and touch screen displays at approximately 50 locations in the factory. These clients communicate over a wireless LAN to application servers. The software is written in Java Enterprise Edition.
Tooling to string the fibers and custom equipment to test the leak integrity, fiber light loss, and flatness of the modules is integrated with the system. The system handles all aspects of the factory operation: assembly tasks, test data collection, storage, and checking, inventory, personnel scheduling and training, machine maintenance and calibration, data backup and synchronization. A web interface provides views of the data. Large format displays throughout the factory provide alarms and dashboards to present relevant information for each location.
An earlier version of the system was used to produce 500 modules for the NOvA near detector. Further development and improvements are in progress as we prepare to assemble the first far detector modules.
Author
Dr
Alex Smith
(University of Minnesota)
