Extended Observation of Solar COsmic Radiation (EOSCOR)


The EOSCOR experiment, designed and built at Case Western Reserve University (CWRU) in the late 1970's, was intended to observe solar neutrons on an extended duration balloon mission. The fundamental operation of the experiment involved two large area (1 m2) plastic scintillator sheets, separated by 1 m. Neutrons were detected by n-p scattering in each plastic scintillator sheet. Each plastic sheet was read out on all four sides by a single PMT coupled to an isochronous light guide. (At the time, these were the largest such light guides ever fabricated.) The timing signals from all four sides were used to determine event location. The upper and lower sides of the experiment were also covered by a thin segmented plastic scintillator that acted as an antocoincidence detector. My work on EOSCOR involved the fabrication of EOSCOR-III detector (shown here) during the 1978-1980 timeframe. This was later taken to the Indiana University Cyclotron Facility (IUCF) for neutron calibration. Eventually, EOSCOR-III was launched on a long duration balloon mission from Alice Springs, Australia. After circumnavigating the globe, an attempt was made to terminate the flight as it passed over Australia. The initial attempts to do so failed. Termination was not achieved until it was out over the Indian Ocean. Although some data was telemetered during the mission, all hardware was lost.





Photo Album

Early fabrication, showing partial assembly of lower detector layer. Here one can see that two of the four light guides are in place.
Each light pipe had to be glued to the (tongue-and-groove) edge of the plastic scintillator. Here the fourth light pipe for the lower layer has been glued and is being allowed to set.


Initial assembly of the lower layer is complete and the upper scintillator panel has been set in place. All scintillator and light pipes were first wrapped in aluminum foil for reflectance and then with black polyurethane for light-tightness.
The light guides of the upper layer are being set in place. Note that the upper light guide leads down to a PMT location that lies outide of the PMT location of the lower light guides.

A closeup view of one of the scintillator - light guide seams. Note the blue color of the scintillator and the groove that runs along the edge of the scintilltor.


A later stage in the assembly of the upper detector assembly.
The initial assembly of the both the upper and lower detector layers has been completed and the entire detector has been raised in preparation for later assembly stages.


Rocky Koga (now at Aerospace Corp.) shown working with EOSCOR's on-board microprocessor. Remember, this was several years before the IBM PC.
Neutron calibration at IUCF. The entire detector has been turned on its side. Note the four separate panels (each with a single PMT) that comprise the top anticoincidence panel. Glenn Frye (right) was PI for the EOSCOR project.


The very first step in the EOSCOR assembly was placing the lower scintillator into place within the frame. That's Steve Schindler, who left for CalTech not long after this photo was taken.
The sate-of-the-art in data acquisition - a PDP 8.

Last Updated: January 24, 2000